Multiple drug intolerance syndrome: prevalence, clinical characteristics, and management

Multiple drug intolerance in antihypertensive patients: what is known and what is missing

Drug allergy and intolerance are increasingly recognized as significant public health concerns, leading to adverse reactions in patients undergoing pharmacological treatments. Multiple drug intolerance syndrome (MDIS), characterized by adverse reactions to at least three different drug classes without a clear immunological mechanism, poses a substantial challenge, particularly in hypertensive patients. Despite its link to suboptimal adherence and uncontrolled blood pressure, MDIS in the context of hypertension remains insufficiently explored. This review synthesizes existing literature on MDIS, emphasizing clinical characteristics, pathogenesis, and psychiatric comorbidity. Furthermore, it delves into MDIS in the context of hypertension, highlighting the importance of a multidisciplinary approach in diagnosis and management, including innovative therapeutic strategies such as novel therapeutic algorithms or renal denervation. The review concludes by emphasizing the necessity for further research and clinical trials to enhance our understanding and address MDIS, especially in hypertensive patients.

Is Penicillin Allergy a Clinical Problem? A Systematic Review of Total Joint Arthroplasty Procedures With Implications for Patient Safety and Antibiotic Stewardship

BACKGROUND

Patients undergoing total joint arthroplasty (TJA) who report penicillin allergy (PA) are frequently administered second-line antibiotics, although recent evidence suggests that this may be unnecessary and could increase infection risk. Many institutions have aimed to improve antibiotic deployment via allergy testing and screening; however, there is little standardization to this process. This review aimed to evaluate (1) antibiotic selection in patients who report PA and assess the impact of screening and testing interventions, (2) rates of allergic reactions in patients who report PA, and (3) the association between reported PA and screening or testing programs and odds of surgical site infection or periprosthetic joint infection.

METHODS

PubMed, EBSCOhost, and Google Scholar electronic databases were searched on February 4, 2023 to identify all studies published since January 1, 2000 that evaluated the impact of PA on patients undergoing TJA (PROSPERO study protocol registration: CRD42023394031). Articles were included if full-text manuscripts in English were available, and the study analyzed the impact of PA and related interventions on TJA patients. There were 11 studies evaluating 1,276,663 patients included. Interventions were compared via presentation of key findings regarding rates of clinically relevant or high-risk PA reported upon screenings or testings, cephalosporin utilizations, allergic reactions, and postoperative infections (surgical site infection and periprosthetic joint infection).

RESULTS

All 6 studies found that PA screening and testing markedly increase the use of first-line antibiotics. Testing showed low rates of true allergy (0.7 to 3%) and allergic reaction frequency for patients who have reported PA receiving cephalosporins was between 0% and 2%. Although there were mixed findings across studies, there was a trend toward second-line antibiotic prophylaxis being associated with a slightly higher rate of infection in PA patients.

CONCLUSIONS

Using PA screening and testing can promote antibiotic stewardship by safely increasing the use of first-line antibiotics in patients who have a reported PA.

LEVEL OF EVIDENCE

Level III, Therapeutic Study.

Analysis of Allergy and Hypersensitivity Reactions to COVID-19 Vaccines According to the EudraVigilance Database

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic presented a new challenge in modern medicine: the development of vaccines was followed by massive population vaccinations. A few reports on post-vaccination allergic reactions have made patients and medical personnel uneasy as to COVID-19 vaccines' allergic potential. Most of the studies in this area to date have been small, and some that were based on global databases skipped most of the allergic diseases and concentrated only on anaphylaxis. We aimed to analyze the incidence of serious allergic reactions based on the EudraVigilance (EV) database, regardless of the reported symptoms and allergy mechanism.

METHODS

The total number of administrated vaccine doses was extracted on 5 October 2023 from Vaccine Tracker and included all administrations since vaccinations began in the European Economic Area (EEA). Data on serious allergic reactions to COVID-19 vaccines were extracted from the EudraVigilance database with the same time point. The code names of 147 allergic symptoms or diseases were used.

RESULTS

The frequency of serious allergic reactions per 100,000 administered vaccine doses was 1.53 for Comirnaty, 2.16 for Spikevax, 88.6 for Vaxzevria, 2.11 for Janssen, 7.9 for Novavax, 13.3 for VidPrevtyn Beta, and 3.1 for Valneva. The most prevalent reported reactions were edema (0.46) and anaphylaxis (0.40). Only 6% of these reactions were delayed hypersensitivity-oriented.

CONCLUSIONS

The overall frequency of potential serious allergic reactions to COVID-19 is very rare. Therefore, COVID-19 vaccines seem to be safe for human use. The lowest frequency of allergic reaction was observed for Comirnaty and the highest for Vaxzevria.

Drug Allergy Mimics

When approaching a case of apparent drug allergy, the consulting clinician should consider a broad differential diagnosis. This article presents a series of cases that could be commonly referred to an allergist for assessment as "drug allergy," however, a real diagnosis exists that mandates a different diagnostic and treatment strategy, including a case of inducible laryngeal obstruction, multiple drug intolerance syndrome, viral rash, seizure due to metastatic malignancy, and hemophagocytic lymphohistiocytosis initially diagnosed as drug reaction and eosinophilia with systemic symptoms. The initial misdiagnoses of these patients delayed or interfered with their medical care, emphasizing the importance of accurate diagnoses for the benefit of our patients.

Severe Multiple Drug Intolerance Syndrome in Fibromyalgia and Irritable Bowel Syndrome

BACKGROUND

Multiple drug intolerance syndrome (MDIS) describes patients with multiple nonimmunologically mediated adverse reactions to medications. Patients with more than 10 medication intolerance labels are considered to have severe MDIS. There is overlap in the characteristics of patients with MDIS and fibromyalgia and irritable bowel syndrome (IBS). Severe MDIS can limit treatment options in this already complex patient group.

OBJECTIVE

This study assessed the prevalence of severe MDIS in patients with fibromyalgia and IBS and its associated risk factors.

METHODS

A retrospective chart review identified patients diagnosed with fibromyalgia or IBS who had been seen at a large academic center from August 2019 to July 2020. Exact birthdate- and sex-matched controls who had been seen within the same time frame were selected at random. Listed drug intolerance data and patient characteristics were then analyzed with logistic regression and χ2 testing.

RESULTS

Patients with fibromyalgia and IBS were 12 and 3 times more likely to have severe MDIS compared with controls, respectively. Severe MDIS was associated with polypharmacy in both groups. Opiates were the most frequently reported drug intolerance across all participants. Although patients with IBS more often reported gastrointestinal symptoms as adverse reactions, individuals with fibromyalgia did not more frequently report pain or behavioral changes as adverse reactions.

CONCLUSIONS

There was an increased rate of severe MDIS in patients diagnosed with fibromyalgia and IBS. Additional studies are needed to better understand the morbidity of MDIS and how it can best be managed in patients with fibromyalgia and IBS.

Penicillin Allergy Testing and Delabeling for Patients Who Are Prescribed Penicillin: A Systematic Review for a World Health Organization Guideline

Secondary prevention with penicillin aims to prevent further episodes of acute rheumatic fever and subsequent development of rheumatic heart disease (RHD). Penicillin allergy, self-reported by 10% of the population, can affect secondary prevention programs. We aimed to assess the role for (i) routine penicillin allergy testing and the (ii) safety of penicillin allergy delabeling approaches in this context. We searched MEDLINE, Embase, CENTRAL, ClinicalTrials.gov, WHO ICTRP, ISRCTN, and CPCI-S to identify the relevant reports. We found 2419 records, but no studies addressed our initial question. Following advice from the WHO-Guideline committee and experts, we identified 6 manuscripts on allergy testing focusing on other populations showing that the prevalence of allergy confirmed by testing was low and the incidence of life-threatening reactions to BPG was very low (< 1-3/1000 individuals treated). A subsequent search addressed penicillin allergy delabeling. This found 516 records, and 5 studies addressing the safety of direct oral drug challenge vs. skin testing followed by drug administration in patients with suspected penicillin allergy. Immediate allergic reactions of minor severity were observed for a minority of patients and occurred less frequently in the direct drug challenge group: 2.3% vs. 11.5%; RR = 0.25, 95%CI 0.15-0.45, P < 0.00001, I2 = 0%. No anaphylaxis or deaths were observed. Severe allergic reactions to penicillin are extremely rare and can be recognized and dealt by trained healthcare workers. Confirmation of penicillin allergy diagnosis or delabeling using direct oral drug challenge or penicillin skin testing seems to be safe and is associated with a low rate of adverse reactions.

The relationship between sensory processing sensitivity and medication sensitivity: brief report

Sensory processing sensitivity (SPS) is a biological/temperament trait that is associated with greater awareness of and reactivity to the environment, which results in amplified responses to various stimuli, and possibly medications. We investigated the relationship between SPS and medication sensitivity in three studies. Participants (ages 18-81) were recruited from university (Study 1: N = 125; Study 2: N = 214) and online (Study 3: N = 351) samples. In each study, participants completed a medication sensitivity scale, the standard highly sensitive person (HSP) scale to assess SPS, and a negative affectivity (NA) scale as a control variable. All three studies found moderate, significant correlations between SPS and medication sensitivity (r = 0.34, p < 0.001: r = 0.21, p = 0.003; r = 0.36, p < 0.001, respectively). Correlations remained significant, and similar, when controlling for NA and gender; and there were no significant interactions with gender. In sum, our results suggest that SPS is associated with medication sensitivity, even when considering NA and gender. Thus, future work might consider SPS when investigating recommended medication, medication dosage, effectiveness, and adverse drug reactions.

Clarification of adverse drug reactions by a pharmacovigilance team results in increased antibiotic re-prescribing at a freestanding United States children's hospital

Documentation of adverse drug reactions (ADRs) is a key factor in guiding future prescribing. However, incomplete documentation is common and often fails to distinguish implicated drugs as true allergies. This in turn leads to unnecessary avoidance of implicated drug classes and may result in sub-optimal prescribing. Pharmacovigilance (PV) programs utilize a systematic approach to clarify ADR documentation and are known to improve patient safety. Yet it remains unclear if PV alters prescribing. Or, if the existence of the ADR documentation itself continues to prompt avoidance of implicated drugs. To address this, our work presents a retrospective cohort study assessing if clarification of antibiotic ADRs by a hospital-wide PV team was associated with future, safe, re-prescribing at a freestanding pediatric hospital in the midwestern United States. First, we compared the likelihood of future prescribing in an antibiotic class with an active ADR, as compared to alternative drug classes, between PV-clarified and non-clarified patients. Second, we assessed differences in adverse event rates 30-days after future prescribing based on PV clarification status. For robustness, analyses were performed on patients with ADRs in four antibiotic classes: penicillin-based beta-lactams (n = 45,642), sulfonamides/trimethoprim (n = 5,329), macrolides (n = 3,959), and glycopeptides (n = 622). Results illustrate that clarification of an ADR by PV was associated with an increased odds of future prescribing in the same drug class (Odds Ratio [95%-CI]): penicillin-based beta-lactams (1.59 [1.36-1.89]), sulfonamides/trimethoprim (2.29 [0.89-4.91]), macrolides (0.77 [0.33-1.61]), and glycopeptide (1.85 [1.12-3.20]). Notably, patients clarified by PV experienced no increase in the rate of adverse events within 30-days following the prescribing of antibiotics in the same class as an active ADR. Overall, this study provides strong evidence that PV reviews safely increase the rate of re-prescribing antibiotics even in the presence of an existing implicated drug ADR.

Risk factors for allergy documentation in electronic health record: A retrospective study in a tertiary health center in Switzerland

BACKGROUND

Most hospitals use electronic health records (EHR) to warn health care professionals of drug hypersensitivity (DH) and other allergies. Indiscriminate recording of patient self-reported allergies may bloat the alert system, leading to unjustified avoidances and increases in health costs. The aim of our study was to analyze hypersensitivities documented in EHR of patients at Lausanne University Hospital (CHUV).

METHODS

We conducted a retrospective study on patients admitted at least 24 h to CHUV between 2011 and 2021. After ethical clearance, we obtained anonymized data. Because culprit allergen could be either manually recorded or selected through a list, data was harmonized using a reference allergy database before undergoing statistical analysis.

RESULTS

Of 192,444 patients, 16% had at least one allergy referenced. DH constituted 60% of all allergy alerts, mainly beta-lactam antibiotics (BLA) (30%), NSAID (11%) and iodinated contrast media (ICM) (7%). Median age at first hospitalization and hospitalization length were higher in the allergy group. Female to male ratio was 2:1 in the allergic group. Reactions were limited to the skin in half of patients, and consistent with anaphylaxis in 6%. In those deemed allergic to BLA, culprit drug was specified in 19%, 'allergy to penicillin' otherwise. It was impossible to distinguish DH based on history alone or resulting from specialized work-up.

CONCLUSIONS

Older age, longer hospital stays, and female sex increase the odds of in-patient allergy documentation. Regarding DH, BLA were referenced in 4% of inpatient records. Specific delabeling programs should be implemented to increase data reliability and patient safety.

Patient Adherence to Written Instructions following Complete Allergological Evaluation for Suspected Beta-Lactam Allergy: A Tertiary Hospital Study in Greece

BACKGROUND

Beta-lactam (BL) antibiotics are among the most prescribed groups of drugs worldwide and have been implicated in a variety of allergic reactions. There is a paucity of literature regarding patient adherence to prescribed instructions following comprehensive allergy assessments.

OBJECTIVE

The objective was to follow up the clinical course of BL allergy in patients who underwent thorough allergological investigation for suspected BL allergy at a tertiary hospital and ascertain patients' compliance with the provided written instructions.

MATERIALS

An observational study in patients referred for suspected BL allergy who underwent a comprehensive allergy workup (in vivo ± in vitro tests, DPT in culprit and/or alternative BL) and who subsequently received written instructions was conducted. Data on the nature of the reported drug hypersensitivity reaction, the culprit BL drug, the allergological workup, and the detailed instructions provided in a written drug allergy report were collected retrospectively. Patients' compliance with the instructions was recorded by a telephone survey using a pre-defined questionnaire.

RESULTS

Among the 212 patients meeting the inclusion criteria, 87 patients (72.4% women; mean age 50.1 years; age range 6-84 years) responded to the telephone survey and were included in this study. Surprisingly, 45 out of 87 (51.7%) patients did not adhere to the written instructions. The primary factor contributing to non-compliance was the fear of re-occurrence of a drug-induced allergic reaction (personal and/or triggered by their treating physician reluctance), accounting for 77.7% of cases. The analysis demonstrated that the initial reaction's severity and type, as well as the outcomes of skin testing, did not correlate with compliance to instructions (p > 0.05). Surprisingly enough, a drug provocation test (DPT), irrespectively of the result, emerged as a negative predictor for adherence, with only 40.6% of DPT patients complying compared to 77.8% of those who did not undergo DPT (p = 0.005; odds ratio = 0.195; 95% confidence interval: 0.058-0.655). Variables such as performing DPT with alternative or incriminated drugs or the result of the DPT (positive-negative) were not associated with patient compliance. Conversely, the type of instructions provided exhibited a noteworthy correlation with compliance. Patients who were explicitly instructed to entirely avoid all BL antibiotics demonstrated markedly higher adherence rates (83.3%) compared to those who were advised to have a partial or complete release of BLs (31.8% and 58.1%, respectively; p < 0.05). Notably, among compliant patients who received either the original culprit drug or the alternative (32 out of 87, 36.7%), no allergic reactions were reported. In contrast, among the 12 patients with written avoidance of all BLs, subsequent BL intake led to immediate reactions (Grade I and IV) in 2 patients (16.6%).

CONCLUSIONS

A notable disparity in patient adherence to written instructions prohibiting or releasing beta-lactams was demonstrated. Less than half of the patients ultimately complied with the provided instructions, underscoring the need for tailored patients' education and strategies to improve adherence in the management of suspected BL allergy.

Penicillin Allergy Evaluation Should Be Performed Proactively in Patients With a Penicillin Allergy Label

Penicillin allergy is the most common drug allergy in the US population. A penicillin allergy label is associated with poor patient outcomes including increased hospital length of stay, increased perioperative infections, and overall increased mortality. A penicillin allergy evaluation accurately identifies approximately 9 of 10 patients who, despite reporting a history of penicillin allergy, can receive penicillins safely. Penicillin allergy evaluations should be offered proactively to healthy patients during routine visits, including children and pregnant women, in advance of antibiotic need.

Drug Allergy in Women

Across all settings, women self-report more drug allergies than do men. Although there is epidemiologic evidence of increased drug allergy labeling in postpubertal females, the evidence base for female sex as a risk factor for true immune-mediated drug hypersensitivity reactions (DHRs), particularly in fatal drug-induced anaphylaxis, is low. A focus on the known immunologic mechanisms described in immediate and delayed DHR, layered on known hormonal and genetic sex differences that drive other immune-mediated diseases, could be the key to understanding biological sex variations in DHR. Particular conditions that highlight the impact of drug allergy in women include (1) pregnancy, in which a drug allergy label is associated with increased maternal and fetal complications; (2) multiple drug intolerance syndrome, associated with anxiety and depression; and (3) female-predominant autoimmune medical conditions in the context of mislabeling of the drug allergy or increased underlying risk. In this review, we describe the importance of drug allergy in the female population, mainly focusing on the epidemiology and risk, the mechanisms, and the associated conditions and psychosocial factors. By performing a detailed analysis of the current literature, we provide focused conclusions and identify existing knowledge gaps that should be prioritized for future research.

Improving the Documentation of Penicillin Allergy Labels Among Pediatric Inpatients

BACKGROUND AND OBJECTIVES

Penicillin allergy is the most common medication allergy, and the penicillin allergy label is commonly over-applied without adequate reaction history inquiry or documentation. Because penicillin allergy labels are often applied in childhood and carried into adulthood, we sought to increase the completeness of reaction history documentation from 20% to 70% for pediatric hospital medicine patients and from 20% to 50% for all other pediatric inpatients within 12 months. As a secondary outcome, we also aimed to increase the proportion of delabeling unnecessary penicillin labels to 20% for all pediatric inpatients.

METHODS

To address our aims, our quality improvement initiative included education for pediatric faculty and staff, development and implementation of a clinical pathway for allergy risk stratification, and electronic health record optimizations. Statistical process control charts were used to track the impact of the interventions facilitated by an automated dashboard.

RESULTS

Within 12 months of interventions, the completeness of allergy labels improved from 20% to 64% among patients admitted to the pediatric hospital medicine service and improved from 20% to 45% for all other pediatric inpatients. The frequency of penicillin allergy delabeling remained unchanged; however, 98 patients were risk stratified and 34 received outpatient allergy referrals for further testing. The number of adverse drug reactions to penicillin, a balancing measure, did not change during the study period.

CONCLUSIONS

We increased the completeness of penicillin allergy documentation using a standardized workflow facilitated by a multidisciplinary clinical pathway. With ongoing efforts, more penicillin delabeling in low-risk patients is anticipated.

Diagnostic Evaluation of Hypersensitivity Reactions to Antibiotics in a Large Cohort of Mastocytosis Patients

BACKGROUND

Anaphylactic reactions are a well-known feature of mastocytosis, particularly in relation to hymenoptera venom stings. Although data on the frequency of drug hypersensitivity reactions is limited in mastocytosis, it is hypothesized that these patients may be predisposed to hypersensitivity reactions to certain drugs, including antibiotics. Nevertheless, this issue has not been systematically investigated. Thus, we investigate the prevalence and clinical features of hypersensitivity reactions to antibiotics (HRA) in mastocytosis.

METHODS

A 15-year retrospective study was conducted among 239 (≥18 years old) consecutive mastocytosis patients who were investigated in our center. All patients underwent a thorough allergy work-up, where self-reported reactions were individually evaluated by an allergist.

RESULTS

Overall, 34 patients (14.2%) were deemed to have HRA. Most patients reacted with cutaneous symptoms (74%), and anaphylaxis was rare, confirmed only in two of 34 patients (0.8%). Beta-lactams were the most common elicitors (63%). There were no differences in age, gender, atopic status and tryptase levels between mastocytosis patients with and without antibiotic hypersensitivity.

CONCLUSIONS

The present study indicates a similar prevalence of HRA in mastocytosis compared to those of the general population. Moreover, antibiotics appear to be rare elicitors of anaphylaxis in these patients. Hence, our results suggest that mastocytosis patients without a history of HRA may be treated with these drugs without special precautions.

Delabelling multiple antibiotic allergy: Practical issues

With the growing incidence of multi-drug resistant organisms, delabelling incorrect antibiotic allergies has become an integral part of antimicrobial stewardship worldwide. For example, around 90% of penicillin allergy labels are found to be inaccurate following a full allergy work-up, which deprive patients the use of effective first-line penicillin antibiotics and increase the risk of antimicrobial resistance with the use of other extended spectrum non-penicillin antimicrobials. Significant numbers of adult and paediatric patients over time are labelled with multiple penicillin and non-penicillin antibiotic allergies often during inappropriate antimicrobial use, resulting in a label of “multiple antibiotic allergy”. In contrast to delabelling penicillin allergy where oral direct provocation tests can be used for low-risk, mild reactions, and sensitivity/specificity/positive and negative predictive values of skin tests have been demonstrated, diagnostic tests for multiple antibiotic allergy often require the use of a combination of in-vivo and in-vitro tests across different antimicrobial classes for evaluation. Shared decision making with patients and informed consent are also needed when prioritising which drugs to delabel first, balancing the risks, benefits of testing vs. interim use of alternative antibiotics. Similar to delabelling penicillin allergy, the cost-effectiveness of delabelling multiple drug allergies is unknown.

Association between urban garbage exposure and allergic diseases among sanitation practitioners: A cross-sectional study

Background

The prevalence of allergic diseases has increased significantly in China over the last few decades, and there have been very few reports of allergic diseases in certain occupational specialties, with almost no reports among sanitation workers.

Objective

Our objective was to investigate the prevalence of allergic diseases and the prevalence of common allergen sensitization in the population engaged in sanitation, and to try to answer the connection between urban garbage waste exposure and the development of allergic diseases.

Methods

We conducted a cross-sectional survey of people working in sanitation-related jobs in Liwan District, Guangzhou, China. A total of 893 people completed the questionnaire for this study, and 500 of them were further screened and tested for allergens specific IgE and IgG4. Combining the questionnaire and test results, we investigated the incidence of allergy disorders and patterns of sensitization to allergens in this community, and evaluated the presence of occupational-related risk factors in this particular population.

Results

Of the 893 sanitation workers, 166 (18.59%) self-reported allergic diseases, predominantly suffering from allergic rhinitis (AR) (n = 98, 10.97%), followed by drug allergy (n = 31, 3.47%), atopic dermatitis (n = 27, 3.02%), food allergy (n = 21, 2.35%), and asthma (n = 9, 1.00%), in that order. In addition to dust mites (32.20%), which had the highest sensitization rate, the subject population had relatively high sensitization rates to ragweed (7.00%) and moulds mixture (8.20%) when compared with the rates of sensitization to moulds and ragweed in the general population; the top 3 sIgG4 positivity rates were egg (50.00%), milk (10.20%), and soybean (9.40%). The prevalence of self-reported AR was higher in office managers (the control group) than in cleaning staff (the exposed group), but there was no difference in sIgE positivity for serum allergens between the 2 groups. The chance of having AR may increase with management positions (crude OR 2.20, 95% CI 1.38-3.50), P = 0.001).

Conclusion

This is the first study to investigate the prevalence of allergy illnesses in the sanitation workforce in mainland China. We identified a community of real sanitation workers with high ragweed and mycobacterial sensitization rates. Urban cleaning may be protective factor against AR at the symptom level, but the serological results did not show this to be the case.

Comparative Effectiveness, Safety, and Real-World Outcomes of a Nurse-Led, Protocol-Driven Penicillin Allergy Evaluation From the Hong Kong Drug Allergy Delabelling Initiative (HK-DADI)

BACKGROUND

There is a high prevalence of unconfirmed penicillin allergy, which is associated with a multitude of adverse clinical outcomes. With the overwhelming burden of currently incorrect labels and the lack of allergy specialist services, new delabeling strategies are urgently needed.

OBJECTIVE

To assess the effectiveness, safety, and real-world outcomes of a nurse-led, protocol-driven evaluation of penicillin allergy, the Hong Kong Drug Allergy Delabelling Initiative (HK-DADI).

METHODS

Adult patients with suspected penicillin allergy were recruited into HK-DADI. Allergy and postdelabeling outcomes were retrospectively compared between patients evaluated via HK-DADI or traditional allergist evaluation.

RESULTS

A total of 312 completed penicillin allergy evaluation: 84 (27%) and 228 (73%) via HK-DADI and traditional pathways, respectively. Overall, 280 penicillin allergies were delabeled (90%). The delabeling rate between HK-DADI and traditional pathways was similar (90% vs 89%; P = .796). Among patients of the HK-DADI pathway, the delabeling rate was significantly higher among low-risk (LR) compared with non-LR patients (97% vs 77%; P = .010). Skin tests did not add diagnostic value among LR patients. No patients developed severe or systemic reactions during the evaluation. Upon 6- to 12-month follow-up (median, 10 months), 123 patients experienced infective episodes (44%) and 63 used penicillins again after delabeling (23%). This proportion was significantly higher in patients who were delabeled via HK-DADI compared with the traditional pathway (32% vs 19%; P = .026).

CONCLUSIONS

The Hong Kong Drug Allergy Delabelling Initiative, a nurse-led, protocol-driven evaluation, was safe and effective in penicillin allergy delabeling. It led to an even higher rate of future penicillin use after delabeling and mitigated the need for unnecessary skin testing among LR patients.

The Evolution of Our Understanding of Penicillin Allergy: 1942-2022

This article reviews our evolving understanding of penicillin hypersensitivity at the 80th anniversary of penicillin's clinical introduction. Penicillin breakdown products covalently bond to serum proteins, leading to classic drug hypersensitivity. Penicillin remains the most frequently reported drug "allergy." Adverse reactions were presumed, in retrospect incorrectly, to implicate a risk for anaphylaxis, and therefore skin testing for IgE became the focus. Skin test positivity may wane over time. This insight has led to the radical conclusion that penicillin hypersensitivity may not be "forever." Atopic background, other drug allergies, family history, gender, and race are apparently not risk factors for penicillin hypersensitivity. Confirmed penicillin hypersensitivity has declined since the 1960s, potentially due to "cleaner" penicillin products and lower dose oral, instead of parenteral, use. Avoiding penicillins, without evaluation, caused unanticipated problems that have been appreciated only recently including longer hospital stays, increased cost of care, suboptimal outcomes from serious infections, and greater toxicities and costs with alternative antibiotics. There are personal and public health advantages with broadly implemented penicillin allergy delabeling based on a reaction history-based risk assessment. Limited skin testing followed by an oral challenge, if negative, for higher-risk histories, and direct oral challenges in lower-risk individuals are currently the reference standard tests to confirm current tolerance.

Patient Characteristics Associated With Reactions to Mrgprx2-Activating Drugs in an Electronic Health Record-Linked Biobank

BACKGROUND

Mas-related G protein-couple receptor x2 (Mrgprx2) activation underlies many common non-IgE-mediated adverse drug reactions (ADRs), yet the features of patients with reactions to Mrgprx2-activating drugs are unknown.

OBJECTIVE

To characterize the patient-specific comorbidities and laboratory characteristics associated with listed reactions to Mrgprx2-activating drugs, including fluoroquinolones, morphine, neuromuscular blockade agents, vancomycin, and leuprolide.

METHODS

We used a retrospective, observational cohort study design using electronic health record data from adults with an Mrgprx2-activating drug exposure recorded within a hospital system clinical Biobank. Odds ratios (ORs) and incidence rate ratios for clinical characteristics associated with ADRs, including immediate hypersensitivity reactions, were calculated using multivariable logistic regression.

RESULTS

Among 59,763 patients exposed to Mrgprx2-activating drugs, 4846 had a listed ADR. Female sex, White race, asthma (OR: 1.81, 95% confidence interval [CI]: 1.68-1.94), chronic urticaria (OR: 1.73, 95% CI: 1.46-2.05), and mastocytosis (OR: 12.79, 95% CI: 5.98-27.02) were associated with increased odds of a reaction. Overall, patients with allergic disease had 1.21 times the rate of an ADR compared with patients without allergic disease. Elevated absolute eosinophil count was inversely associated with reactions, and there was no association with elevated total IgE. Observed associations were similar in a patient subgroup with immediate-type hypersensitivity reactions.

CONCLUSION

Specific allergic diseases and common allergic biomarkers are differentially associated with ADRs to Mrgprx2-activating drugs. These findings from a large, "real world" drug-exposed population highlight clinical factors that may contribute to non-IgE-mediated drug allergy.

Advances in the Understanding of Drug Hypersensitivity: 2012 Through 2022

Over the last decade there have been key advances in understanding mechanisms, risk, and consequences of both true immunological drug hypersensitivity and unverified drug allergy labels that have changed clinical practice. This has been facilitated by the widespread adoption of electronic health records (EHRs). The vast majority of EHR drug allergy labels are unverified and cause significant morbidity from unnecessary avoidance of optimal drug therapy. There has also been significant movement in our understanding of mechanisms of drug hypersensitivity that, in addition to advancing our understanding of the pathogenesis of immediate and delayed reactions, have guided preventive efforts, diagnostic procedures, and clinical management. More widespread adoption, including scale-up of "allergy" delabeling and appropriate management, specifically for antibiotics, opiates, radiocontrast, chemotherapeutics, biologics, and nonsteroidal anti-inflammatory medications, will be necessary to improve patient outcomes over the next decade. This will require further engagement and collaboration between primary care health care providers, allergists, and other specialists.

Allergy Electronic Health Record Documentation: A 2022 Work Group Report of the AAAAI Adverse Reactions to Drugs, Biologicals, and Latex Committee

The allergy section of the electronic health record (EHR) is ideally reviewed and updated by health care workers during routine outpatient visits, emergency room visits, inpatient hospitalizations, and surgical procedures. This EHR section has the potential to help proactively and comprehensively avoid exposures to drugs, contact irritants, foods, and other agents for which, based on an individual's medical history and/or genetics, there is increased risk for adverse outcomes with future exposures. Because clinical decisions are made and clinical decision support is triggered based on allergy details from the EHR, the allergy module needs to provide meaningful, accurate, timely, and comprehensive allergy information. Although the allergy section of the EHR must meet these requirements to guide appropriate clinical decisions and treatment plans, current EHR allergy modules have not achieved this standard. We urge EHR vendors to collaborate with allergists to optimize and modernize allergy documentation. A work group within the Adverse Reactions to Drugs, Biologicals, and Latex Committee of the American Academy of Allergy, Asthma & Immunology was formed to create recommendations for allergy documentation in the EHR. Whereas it is recognized that the term "allergy" is often used incorrectly because most adverse drug reactions (ADRs) are not true immune-mediated hypersensitivity reactions, "allergy" in this article includes allergies and hypersensitivities as well as side effects and intolerances. Our primary objective is to provide guidance for the current state of allergy documentation in the EHR. This guidance includes clarification of the definition of specific ADR types, reconciliation of confirmed ADRs, and removal of disproved or erroneous ADRs. This document includes a proposal for the creation, education, and implementation of a drug allergy labeling system that may allow for more accurate EHR documentation for improved patient safety.

Impact of Prior Drug Allergies on the Risk, Clinical Features, and Outcomes of Idiosyncratic Drug-Induced Liver Injury in Adults

BACKGROUND

Prior drug allergies are common and may increase susceptibility to adverse medication effects. The aim of this study was to compare the frequency, clinical features, and outcomes of DILI among patients with and without a history of prior drug allergy.

METHODS

The EMR at a large liver referral center was searched for all DILI encounters using ICD-10 T-codes for drug poisoning/toxicity and K-71 codes for toxic liver injury between 10/1/2015 and 9/30/2019. Clinically significant liver injury was identified using predefined laboratory criteria, and cases were adjudicated using a 5-point expert opinion scale: 1/2/3 = probable DILI and 4/5 = non-DILI. Drug allergy was defined as a history of anaphylaxis, hives, rash, or pruritus after drug exposure.

RESULTS

Among 766,930 patient encounters, 127 unique patients met inclusion criteria with 72 (56.7%) cases adjudicated as probable DILI and 55 (43.3%) as non-DILI. In the probable DILI group, the most frequent suspect drug classes were: antimicrobials (41.9%), herbal and dietary supplements (9.5%), and antineoplastics (8.1%). Twenty-three of the 72 DILI patients (31.9%) had a history of drug allergy before the DILI episode compared to 16 (29.1%) of the 55 non-DILI cases (p = 0.89). However, none of the allergy drugs and suspect DILI drugs were the same although many were in the same drug class. DILI patients with a prior drug allergy were more likely to be female (73.9% vs. 44.9%, p = 0.04) and have lower serum bilirubin (4.0 vs. 7.8, p = 0.08) and INR (1.1 vs. 1.6, p = 0.043) levels at presentation. The likelihood of death or liver transplantation among probable DILI cases with prior drug allergy was lower than those without prior drug allergy (0% vs. 8.2%, p = 0.35). The suspect drug was subsequently documented in the "Drug Allergy" section of the EMR in only 23 (31.9%) of the 72 probable DILI patients, and these patients were more likely to present with a rash (7% vs. 2%, p = 0.006) and higher serum bilirubin levels (10.5 vs. 4.7, p = 0.008) compared to those in whom the suspect drug was not listed as "drug allergy."

CONCLUSION

A prior drug allergy history was not associated with a greater likelihood of developing DILI compared to other causes of acute liver injury. However, the probable DILI patients with a history of prior drug allergy tended to have less severe liver injury and clinical outcomes. The low rate of suspect drug documentation in the "Drug Allergy" section of EMR after a DILI episode is of concern and could lead to avoidable harm from inadvertent suspect drug re-challenge.

Characterization, epidemiology and risk factors of multiple drug allergy syndrome and multiple drug intolerance syndrome: A systematic review

Background

Multiple drug allergy and multiple drug intolerance syndrome (MDAS/MDIS) labels are an impediment to clinical care and knowledge regarding these conditions is limited. This systematic review investigated the characterization, epidemiology, risk factors, clinical impact and pharmaco‐economics of MDAS and MDIS.

Methods

Systematic literature search across 11 databases (01 January 2000–06 November 2020) for MDIS, MDAS and related terminology. Studies were reviewed for quality of evidence and risk of bias by employing Critical Appraisal Skills Programme cohort study checklist. A narrative synthesis approach facilitated by systematic textual descriptions, tabulation and thematic analysis was adopted.

Results

There was heterogeneity in terminology and methodology. Few studies applied standard drug allergy diagnostic methods. There is some evidence to suggest that multiple drug hypersensitivity syndrome (MDHS; i.e., confirmed allergies in MDAS) is a distinct clinical entity. Prevalence of MDIS and MDAS labels in unselected & selected populations varied between 2.1%–6.4% & 4.9%–90% and 1.2% & 0%–36% respectively. Reported risk factors included female gender, increasing age, body mass index, anxiety, depression, co‐morbidities, concurrent allergies and increased healthcare utilization. Drugs commonly implicated were antibiotics and non‐steroidal anti‐inflammatory drugs. No studies relating to clinical impact and pharmaco‐economics were found.

Conclusion

There is considerable burden of MDAS and MDIS labels. Data needs cautious interpretation as majority of studies described involved unverified labels. Despite this limitation and heterogeneity of studies, there is some evidence to suggest that MDHS is a distinct clinical entity. Well‐designed multi‐centre studies applying standardized terminology and diagnostic methodology are needed to gain further insight into these conditions.

Association of Sociodemographic Factors With Reported Penicillin Allergy in Pediatric Inpatients

OBJECTIVES

Characterize the association of sociodemographic factors with reported penicillin allergy in pediatric inpatients.

METHODS

We conducted a retrospective cohort study of pediatric inpatients admitted to general pediatric units at an academic medical center with reported penicillin allergy and reaction history. Sociodemographic factors evaluated were gender, age, race, ethnicity, language, and insurance payer. We conducted univariable and multivariable logistic regression models to evaluate associations between demographic variables and penicillin allergy.

RESULTS

Of 3890 pediatric inpatients, 299 (7.7%) had a reported penicillin allergy. The majority of documented reaction histories were hives, rash, or unknown. In univariable analysis, odds of penicillin allergy were lower in patients who identify as Black and who prefer a language other than English, and higher in patients of non-Hispanic/Latino ethnicity, those with private insurance, and with increasing age. In multivariable logistic regression, only Black race (adjusted odds ratio 0.42, 95% confidence interval CI 0.30-0.59) and young age were significantly associated with lower odds of penicillin allergy.

CONCLUSIONS

After adjustment for covariates, Black race was associated with lower odds of reported penicillin allergy in hospitalized children. Penicillin allergy reporting may be an indicator of racial differences in the prescribing of antimicrobial agents, patient-clinician communication, and access to health care.

Protocol of safe vaccination against COVID-19 in patients with high risk of allergic reactions

Background

Sars-CoV-2 infections are hazardous, especially to the elderly and patients with comorbidities. With no efficient treatment available, newly developed vaccines are the only way to change the course of the pandemic. However, reports of allergic reactions resulted in some patients and practicing physicians being concerned about the safety of vaccine administration, particularly in people with severe anaphylactic reactions to multiple or unknown factors in their medical history.This study aimed to develop an allergic work-up protocol based on skin prick tests (SPT), intradermal testing (IDT) and intramuscular provocations, and desensitisation which may contribute to diagnosis and management of anti-COVID-19 vaccine allergy.

Methods

Two hundred and eighty-five patients were enrolled. Two hundred and five of them entered the study based on severe anaphylactic reaction to unknown or multiple factors in their medical history which disqualified them for standard treatment. Another 80 patients were enrolled after developing an allergic reaction to the first dose of one such vaccine. In all subjects, SPT and IDT were performed. Serum tryptase was assessed in 79 patients randomly chosen from the study group.

Results

Two hundred and seventy-seven patients with negative tests were given a vaccine without complications. Seven patients had positive skin tests. In two cases, tests confirmed Comirnaty allergy, while the other five confirmed solely skin sensitisation with no exposure prior to the study. Six patients with positive tests received titrated challenge using desensitisation protocol with a reasonable tolerance. One patient did not consent to desensitisation and one patient resigned despite negative tests. Overall, 283 (99%) patients were vaccinated using this newly developed protocol. Patients with adverse reactions to the first dose of the vaccine before the study had a significantly lower basal serum tryptase concentration (p = 0.001).

Conclusion

Skin tests with anti-COVID-19 vaccines are a useful tool in the vaccination protocol. This protocol enables safe immunisation of high-allergy-risk patients even in cases of positive skin tests.

The Use of Electronic Health Records to Study Drug-Induced Hypersensitivity Reactions from 2000 to 2021

Electronic health records (EHRs) have revolutionized the field of drug hypersensitivity reaction (DHR) research. In this systematic review, we assessed 140 articles from 2000-2021, classifying them under six themes: observational studies (n=61), clinical documentation (n=27), case management (n=22), clinical decision support (CDS) (n=18), case identification (n=9), and genetic studies (n=3). EHRs provide convenient access to millions of medical records, facilitating epidemiological studies of DHRs. Though the goal of CDS is to promote safe drug prescribing, allergy alerts must be designed and used in a way that supports this effort. Ultimately, accurate allergy documentation is essential for DHR prevention.

Population-Based Incidence, Severity, and Risk Factors Associated with Treated Acute-Onset COVID-19 mRNA Vaccination-Associated Hypersensitivity Reactions

BACKGROUND

COVID-19 mRNA vaccination-associated acute-onset hypersensitivity reactions have caused anxiety and may be contributing to vaccine hesitancy.

OBJECTIVE

To determine the incidence, severity, and risk factors for treated acute-onset COVID-19 mRNA vaccination-associated hypersensitivity reactions in a well-characterized population.

METHODS

All Kaiser Permanente Southern California (KPSC) members who received COVID-19 mRNA vaccinations between December 15, 2020, and March 11, 2021, at a KPSC facility were identified and characterized, along with all treated acute-onset vaccination-associated hypersensitivity events.

RESULTS

We identified 391,123 unique vaccine recipients (59.18% female, age 64.19 ± 17.86 years); 215,156 received 2 doses (53.54% Moderna), 157,615 only a first dose (50.13% Moderna) (1961 [1.46%] >2 weeks late getting a second dose), and 18,352 (74.43% Moderna) only a second dose. Only 104 (0.028%) (85.58% female, age 53.18 ± 15.96 years) had treated first dose events, 68 (0.030%) Moderna. Only 32 (0.014%) (93.75% female, age 57.28 ± 17.09 years) had treated second dose events, 21 (0.016%) Moderna. Only 2 (0.00033%) vaccinations resulted in anaphylaxis. Only 27 (20.77%) of those with treated first dose reactions failed to get a second dose. Only 6 of 77 (7.8%) with first dose reactions also had second dose reactions. Individuals with treated events were more likely to be female (P < .0001), younger (P < .0001), and had more pre-existing drug "allergies" (2.11 ± 2.12 vs 1.02 ± 1.41 [P < .0001] for average recipients).

CONCLUSIONS

Treated acute-onset hypersensitivity events were mostly benign, more common with first COVID-19 mRNA vaccine doses, more likely to occur in younger females with typical risk factors associated with multiple drug intolerance syndrome, and very unlikely to be primarily immunologically mediated.

Female sex as a risk factor for penicillin drug allergy in the inpatient setting

Background: Penicillin is the most common reported drug allergy. Previous literature suggests that there is increased prevalence of penicillin drug allergy in female patients in the outpatient setting. However, this is poorly described in the inpatient setting. Objective: This study was performed to determine whether female sex is an independent risk factor for penicillin allergy in the inpatient setting. Methods: A retrospective review of electronic medical records (January 1, 2001-December 31, 2017) was performed for patients with a history of penicillin allergy who underwent penicillin skin testing (PST). Each chart review included the age at initial skin testing, sex, medications, and medical co-morbidities. The study was approved by the institutional review board. Results: 30,883 patients underwent PST with 29,354 and 1,529 occurring in the outpatient and inpatient setting respectively. 170 patients tested positive with a ≥ 5x5 wheal. Of the 170 positive patients, 122 were female (72%) and 48 were male (28%). 15 patients tested positive in the inpatient setting. Of the 1506 adult patients tested in the inpatient setting, 809 were female and 697 were male. 12 females (92.3%) and 1 one male (7.7%) tested positive with a ≥ 5x5 wheal (OR-10.5; 95% CI-1.4-80.8; p-value=0.02). 23 pediatric patients were tested in the inpatient setting. Two pediatric male patients were positive and no female pediatric patients tested positive (OR-1.7; 95% CI-0.5-5.9; p-value=0.5). Conclusion: In the inpatient setting, adult females are 10 times more likely to have a positive PST compared to males. Female sex may be a potential risk factor for objective penicillin drug allergy in the inpatient setting.

A Simple Algorithmic Approach Allows the Safe Use of Cephalosporin in "Penicillin-Allergic" Patients without the Need for Allergy Testing

BACKGROUND

Patients who report a penicillin allergy are often given second-line antibiotic prophylaxis during total joint arthroplasty (TJA), with only a minority of patients undergoing additional consultations and allergy testing. In an effort to increase the use of cephalosporin prophylaxis in TJA, the present study aimed to assess the effectiveness of a simple, protocol-driven penicillin allergy screening program without the need for additional work-up.

METHODS

Following implementation of a questionnaire-based screening protocol in May 2019, all patients scheduled for primary TJA were risk-stratified into low or high-risk categories. The low-risk cohort received cefazolin, and the high-risk cohort received non-cefazolin antibiotics. Patients were monitored prospectively, and data on antibiotic usage and adverse outcomes were documented. The protocol group (n = 2,078) was propensity score matched 1:1 with a control group that included patients who underwent TJA in the same institution prior to implementation of the protocol. The primary end point was the efficacy of the protocol in reducing unnecessary use of non-cephalosporin antibiotics for prophylaxis. Secondary outcomes included the rate of surgical site infections and allergic reactions to the administered antibiotic.

RESULTS

A total of 357 patients (17.2%) reported a penicillin allergy in the protocol group compared with 310 patients (14.9%) with a recorded allergy in the control group (p = 0.052). The number of patients who received non-cephalosporin antibiotics was significantly lower in the protocol group (5.7% compared with 15.2% in the control group; p < 0.001), whereas there was no difference in the rate of total allergic reactions (0.8% compared with 0.7%, respectively; p = 0.857). Of the 239 low-risk patients (66.9%) in the protocol group, only 3 (1.3%) experienced a mild cutaneous reaction following cefazolin administration. There were no differences in the rates of superficial wound, deep periprosthetic, or Clostridioides difficile infections between the protocol and control groups.

CONCLUSIONS

A simple screening protocol allowed two-thirds of patients with a self-reported allergy to receive cefazolin without the need for additional consultations or testing. We believe this protocol can be safely implemented to increase the rate of cefazolin usage without a corresponding increase in the number of allergic reactions.

LEVEL OF EVIDENCE

Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Population-Based Incidence of New Ampicillin, Cephalexin, Cefaclor, and Sulfonamide Antibiotic "Allergies" in Exposed Individuals with and without Preexisting Ampicillin, Cephalexin, or Cefaclor "Allergies"

BACKGROUND

There is a theoretical concern, unconfirmed by population-based challenge data, that clinically significant, immunologically mediated hypersensitivity occurs among β-lactams sharing side chains.

OBJECTIVE

To determine the population-based allergy incidence associated with the use of β-lactams sharing exact R1 side chains (ampicillin, cephalexin, and cefaclor [ACC]), with or without a current ACC allergy or a sulfonamide antibiotic allergy for comparison.

METHODS

All courses of ACC and trimethoprim-sulfamethoxazole used by any Kaiser Permanente California members in 2017 and 2018, with follow-up through January 2019, were identified along with their preexisting antibiotic allergy status and all new antibiotic-specific allergies reported within 30 days of course initiation.

RESULTS

A total of 1,167,713 courses of ACC were administered to individuals. No sulfonamide antibiotic or ACC allergy and 4771 new ACC allergies (0.41%) were reported. Moreover, 130,032 courses of ACC were administered to individuals with a sulfonamide antibiotic allergy; no ACC allergy and 904 new ACC allergies (0.70%) were reported. There were 5,958 courses of ACC administered to individuals with an ACC allergy; 2,341 who also had sulfonamide antibiotic allergy, as well as 52 new ACC allergies (0.87%) were reported.

CONCLUSIONS

The incidence of new ACC allergy reports is minimally and no-specifically increased when a preexisting ACC or sulfonamide antibiotic allergy exists greater than the baseline incidence in the population. This argues against clinically significant, immunologically mediated cross-reactivity among β-lactams sharing exact side chains in individuals with preexisting but unconfirmed β-lactam allergy. Any previously reported, even unrelated antibiotic allergy appears to be a risk factor for reporting a new antibiotic allergy.

Validation of a Brief Screening Instrument for Chemical Intolerance in a Large U.S. National Sample

Background: Chemical intolerance (CI) is characterized by multisystem symptoms triggered by low levels of exposure to xenobiotics including chemicals, foods/food additives, and drugs/medications. Prior prevalence estimates vary from 8–33% worldwide. Clinicians and researchers need a brief, practical screening tool for identifying possible chemical intolerance. This large, population-based study describes the validation of a three-item screening questionnaire, the Brief Environmental Exposure and Sensitivity Inventory (BREESI), against the international reference standard used for assessing chemical intolerance, the Quick Environmental Exposure and Sensitivity Inventory (QEESI). Methods: More than 10,000 people in the U.S. responded to the BREESI and the QEESI in a population-based survey. We calculated the overall prevalence of CI in this sample, as well as by gender, age, and income. Common statistical metrics were used to evaluate the BREESI as a screener for CI against the QEESI. Results: The prevalence estimate for QEESI-defined chemical intolerance in the U.S. was 20.39% (95% CI 19.63–21.15%). The BREESI had 91.26% sensitivity (95% CI: 89.20–93.04%) and 92.89% specificity (95% CI: 91.77–93.90%). The positive likelihood ratio was 12.83 (95% CI: 11.07–14.88), and the negative likelihood ratio was 0.09 (95% CI: 0.08–0.12). Logistic regression demonstrates that the predicted probability of CI increased sharply with each increase in the number of BREESI items endorsed (Odds Ratio: 5.3, 95% CI: 4.90–5.75). Conclusions: Chemical intolerance may affect one in five people in the U.S. The BREESI is a new, practical instrument for researchers, clinicians, and epidemiologists. As a screening tool, the BREESI offers a high degree of confidence in case ascertainment. We recommend: screen with the BREESI, confirm with the QEESI.

Why Was There Ever a Warning Not to Use Cephalosporins in the Setting of a Penicillin "Allergy"?

It is now well-established that avoiding β-lactam antibiotics, when they are the drugs of choice, results in significantly worse long-term global outcomes for patients. Much of this avoidable morbidity has been caused by widespread warnings in electronic health care record systems not to use cephalosporins in the setting of penicillin allergy. High rates, up to 1000-fold higher than now seen, of immunologically mediated reactions were associated with early impure penicillin preparations. This instilled a rational fear of β-lactam-associated anaphylaxis in generations of physicians. In the late 1970s, several editorial comments regarding a potential increased risk to patients given cephalosporins who had a history of a penicillin allergy resulted in the warning that became imbedded in the culture of medicine. Over the past 40 years, compelling data have been developed that refute this warning and showed that the risks of avoiding cephalosporins outweighed the benefits. In late 2017, Kaiser Permanente Southern California completely removed all warnings not to use cephalosporins in the setting of a penicillin allergy. The results have recently been published in JAMA Network Open. This Rostrum article provides some of the backstory on the establishment and removal of this warning for physicians who trained over the past 30 years.

High-throughput framework for genetic analyses of adverse drug reactions using electronic health records

Understanding the contribution of genetic variation to drug response can improve the delivery of precision medicine. However, genome-wide association studies (GWAS) for drug response are uncommon and are often hindered by small sample sizes. We present a high-throughput framework to efficiently identify eligible patients for genetic studies of adverse drug reactions (ADRs) using “drug allergy” labels from electronic health records (EHRs). As a proof-of-concept, we conducted GWAS for ADRs to 14 common drug/drug groups with 81,739 individuals from Vanderbilt University Medical Center’s BioVU DNA Biobank. We identified 7 genetic loci associated with ADRs at P < 5 × 10⁻⁸, including known genetic associations such as CYP2D6 and OPRM1 for CYP2D6-metabolized opioid ADR. Additional expression quantitative trait loci and phenome-wide association analyses added evidence to the observed associations. Our high-throughput framework is both scalable and portable, enabling impactful pharmacogenomic research to improve precision medicine.

Adverse drug reactions are a considerable burden on the healthcare system. Genetic studies can improve our understanding of the pathophysiological mechanisms of adverse drug reactions but have been hindered by small sample sizes. Drug responses are less often recorded than physiological traits and common diseases. Here, we present a high-throughput framework to efficiently identify eligible patients for genetic studies of adverse drug reactions from electronic health records. We validated our approach by conducting genome-wide association studies for adverse reactions to 14 common drug/drug groups with 81,739 individuals from Vanderbilt University Medical Centre’s BioVU DNA Biobank, identifying 7 genetic loci associated with adverse drug reactions. Our high-throughput framework can enable impactful pharmacogenomic research to help develop clinical guidelines for the delivery of the right drug to the right person.

Tackling the Patient with Multiple Drug "Allergies": Multiple Drug Intolerance Syndrome

As populations age, the prevalence of reported drug "allergy" increases, often leading to suboptimal care and increased morbidity because of unnecessary avoidance of safe and effective medications. Evaluation by a drug allergy specialist is often warranted when a patient has more than 2 unrelated drug "allergies" listed in the medical record. In this commentary, we clarify and propose standard terminology to use when evaluating patients with multiple drug allergy labels including and more specifically when diagnosing multiple drug intolerance syndrome and the much rarer multiple drug hypersensitivity syndrome. We review epidemiology and key features of multiple drug intolerance syndrome and multiple drug hypersensitivity syndrome. We summarize the methodologic and practical diagnostic workup and management of individuals with MDIS to assist with the accurate delabeling of drug "allergies" in the electronic health record.

Iodine allergy: Common misperceptions

Disclaimer

In an effort to expedite the publication of articles related to the COVID-19 pandemic, AJHP is posting these manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time.

Purpose

The current evidence regarding iodine-containing compounds and iodine allergy cross-reactivity is reviewed.

Summary

Iodine is an essential human nutrient found in the thyroid gland. It is used in the synthesis of the thyroid hormones thyroxine and triiodothyroxine. Patients who report having adverse reactions to iodine-containing substances are often labelled as having an “iodine allergy,” which can result in delays in care or patients being denied essential ICM or other iodine-containing drugs. A literature review was conducted to evaluate the evidence regarding iodine allergy and iodine-containing drugs. Of 435 articles considered potentially appropriate for full review (plus 12 additional articles included on the basis of references from the eligible articles), 113 could not be obtained. After exclusion of 353 articles that did not meet all inclusion criteria, the remaining 81 articles were included in the review. The results of the literature review indicated that iodine has not been shown to be the allergen responsible for allergic reactions to iodinated contrast media, amiodarone, povidone-iodine, and other iodine-containing compounds.

Conclusion

There is a lack of evidence to support cross-reactivity between iodine-containing compounds in so called iodine-allergic individuals.

Association Between Removal of a Warning Against Cephalosporin Use in Patients With Penicillin Allergy and Antibiotic Prescribing

IMPORTANCE

Electronic health records (EHRs) often include default alerts that can influence physician selection of antibiotics, which in turn may be associated with a suboptimal choice of agents and increased antibiotic resistance.

OBJECTIVE

To examine whether removal of a default alert in the EHR to avoid cephalosporin use in patients with penicillin allergies is associated with changes in cephalosporin dispensing or administration in these patients.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study of a natural experiment included data on patients who had received antibiotic treatment in the hospital or outpatient setting in 2 regions of a large, integrated health system in California from January 1, 2017, to December 31, 2018. Of 4 398 792 patients, 4 206 480 met the eligibility criteria: enrollment in the health system during antibiotic use, availability of complete demographic data, and use of antibiotics outside of the washout period.

INTERVENTIONS OR EXPOSURES

Oral or parenteral antibiotics dispensed or administered after removal of an EHR alert to avoid cephalosporin use in patients with a recorded penicillin allergy.

MAIN OUTCOMES AND MEASURES

Probability that an antibiotic course was a cephalosporin. A multinomial logistic regression model was used to examine the change in rates of cephalosporin use before and after an EHR penicillin allergy alert was removed in 1 of the study regions. Temporal changes in use rates were controlled for by comparing changes in cephalosporin use among patients with or without a penicillin allergy at the site that removed the warning and among patients at a comparison site that retained the warning. Regression models were used to examine adverse events.

RESULTS

Of the 4 206 480 patients who met all inclusion criteria, 2 465 849 (58.6%) were women; the mean (SD) age was 40.5 (23.2) years. A total of 10 652 014 antibiotic courses were administered or dispensed, divided approximately evenly between the period before and after removal of the warning. Before removal of an alert in the electronic health record system to avoid prescribing of cephalosporins to patients with a penicillin allergy at 1 of the 2 sites, 58 228 courses of cephalosporins (accounting for 17.9% of all antibiotic use at the site) were used among patients with a penicillin allergy; after removal of the alert, administration or dispensing of cephalosporins increased by 47% compared with cephalosporin administration or dispensing among patients without a penicillin allergy at the same site and patients at the comparison site that retained the warning (ratio of ratios of odds ratios [RROR], 1.47; 95% CI, 1.38-1.56) . No significant differences in anaphylaxis (9 total cases), new allergies (RROR, 1.02; 95% CI, 0.93-1.12), or treatment failures (RROR, 1.02; 95% CI, 0.99-1.05) were found at the course level. No significant differences were found in all-cause mortality (ratio of ratios of rate ratios [RRRR], 1.03; 95% CI, 0.94-1.13), hospital days (RRRR, 1.04; 95% CI, 0.99-1.10), and new infections (Clostridioides difficile: RRRR, 1.02; 95% CI, 0.84-1.22; methicillin-resistant Staphylococcus aureus: RRRR, 0.87; 95% CI, 0.75-1.00; and vancomycin-resistant Enterococcus: RRRR, 0.82; 95% CI, 0.55-1.22) at the patient level.

CONCLUSIONS AND RELEVANCE

In this cohort study, removal of a warning in the electronic health record to avoid cephalosporin use in patients with penicillin allergies was associated with increased administration and dispensing of cephalosporin. This simple and rapidly implementable system-level intervention may be useful for improvement in antibiotic stewardship.

Functional dystonia: A case-control study and risk prediction algorithm

OBJECTIVE

Functional dystonia (FD) is a disabling and diagnostically challenging functional movement disorder (FMD). We sought to identify historical predictors of FD vs. other primary dystonias (ODs) and develop a practical prediction algorithm to guide neurologists.

METHODS

1475 consecutive new patient medical records were reviewed at an adult/pediatric tertiary-referral dystonia clinic from 2005 to 2017. Ninety-nine met criteria for clinically established FD (85 adults and 14 pediatric), paired with 99 age/dystonia distribution-matched OD. Univariate and multivariate regression analyses were performed to identify predictors of FD and disability. We formed a prediction algorithm, assessed using the area under the receiver operating curve (AUC).

RESULTS

Multivariate logistic regression analysis investigating independent predictors of FD (P < 0.001) followed by development of a prediction algorithm showed that the most robust predictors included abrupt onset, spontaneous resolution/recurrence, pain, cognitive complaints, being on or pursuing disability, lifetime mood/anxiety disorder, comorbid functional somatic disorders, and having ≥3 medication allergies. The prediction algorithm had utility for both adult and pediatric FD, with excellent sensitivity/specificity (89%/92%) and an area under the curve (AUC) 0.95 (0.92-0.98). Greater disability (modified Rankin Scale) independently correlated with a number of functional examination features, unemployment/not attending school, number of medication allergies, and younger age of presentation. FD patients were high health-care utilizers and were more frequently prescribed opiates/opioids and benzodiazepines (P < 0.003).

INTERPRETATION

This case-control study provides an algorithm to guide clinicians in gauging their index of suspicion for a FD, with diagnostic confirmation subsequently informed by neurological examination. While this algorithm requires prospective validation, health-care utilization data underscore the importance and need for more research in FD.

Prevalence of Antibiotic Allergy Labels in a Tertiary Referral Center in Belgium

BACKGROUND

Antibiotic (AB) allergies are among the most frequently occurring adverse drug reactions. In US literature, AB allergy labels (AAL) are reported in 10% to 15% of patients' charts; however, large-scale European analyses are scarce.

OBJECTIVES

To retrospectively assess the prevalence of AAL in a tertiary referral hospital in Belgium between 2010 and 2018.

METHODS

Patients who consulted and/or were hospitalized during the study period, who had been labeled with an AB allergy, were selected for further analysis.

RESULTS

Of 1,009,598 unique patients (outpatients, n = 736,469; inpatients, n = 273,129), 28,147 patients (3%) were registered with 1 or more AAL, being 1% of outpatients (n = 9562) and 7% of inpatients (n = 18,585). Women were more likely to carry an AAL (68%) compared with men (32%, P < .001). In patients with an AAL, 9% had multiple labels and 5% had labels for multiple AB classes. Most frequently, beta-lactams were involved (84% of AAL), followed by quinolones (7%) and sulfonamides and macrolides (both 3%). Moreover, 88% of the reactions were self-reported, mostly being an unspecified rash (53%), whereas only 3% were considered confirmed AAL.

CONCLUSION

With an overall prevalence of 3%, the burden of AAL is less in our Western European center compared with US reports. However, this prevalence most likely still represents an overestimation of genuine AB allergic patients because most labels lack confirmation and/or specifications. Our work indicates that knowledge of the local epidemiology of AAL is necessary to estimate the impact of better allergy labeling and delabeling strategies.

High-cost, high-need patients: the impact of reported penicillin allergy

OBJECTIVES

More than 90% of patients who report a penicillin allergy have the allergy disproved when tested. Unnecessary use of alternative (non-beta-lactam) antibiotics can result in more treatment failures and adverse reactions. We described the prevalence and impact of a reported penicillin allergy in high-cost, high-need (HCHN) patients.

STUDY DESIGN

Retrospective cohort.

METHODS

We identified HCHN patients in a care management program of an urban academic medical center (January 1, 2014, to December 31, 2016). We used multivariable logistic regression models to determine the association between a reported penicillin allergy and antibiotic use. We used multivariable Poisson regression models to determine the association between a reported penicillin allergy, with or without multiple drug intolerance syndrome (MDIS; ≥3 reported drug allergies), and healthcare resource utilization (HRU).

RESULTS

Of 1870 HCHN patients, 383 (20%) reported penicillin allergy, 835 (45%) had MDIS, and 290 (16%) had both. HCHN patients reporting penicillin allergy had an increased odds of beta-lactam alternative antibiotic use (adjusted odds ratio, 3.84; 95% CI, 2.17-6.80). HRU was significantly higher for patients reporting a penicillin allergy alone (adjusted relative risk [aRR], 1.13; 95% CI, 1.03-1.25) and with concurrent MDIS (aRR, 1.20; 95% CI, 1.08-1.34).

CONCLUSIONS

HCHN patients had a high burden of reported drug allergy. A reported penicillin allergy conferred a 4-fold increased odds of beta-lactam alternative antibiotic use. Reporting penicillin allergy, with and without MDIS, was associated with significantly more HRU. HCHN care management programs should consider systematic drug allergy evaluations to optimize antibiotic use in these fragile patients.

Antibiotic allergy as a cause of hospitalization in adults: a hospital-based study in Ukraine

Background:

Antibiotic allergy is an important clinical and social-economical issue.

Objective:

The main objectives of this study were to determine the incidence, causative drugs, and risk groups of antibiotic allergy as a reason for hospitalization. The secondary objective was to evaluate the treatment of antibiotic allergy through the identification of drug related problems (DRPs).

Methods:

This retrospective hospital-based study was carried out in one of Lviv city hospitals (Ukraine) from January 2015 to December 2017. Patients with antibiotic allergy as a cause for hospitalization were included in this study.

Results:

In this study the incidence of antibiotic allergy was 2.0% (95%CI 1.6:2.4) of all admissions to the Unit that provides special medical care for adult inpatients with allergy diseases and allergy reactions. The mean age of patients was 48.5 years (SD=17.0; range 18-83 years) with female predominance (78.2%; 95%CI 68.9:85.2). Antibiotic hypersensitivity reactions manifested as urticaria with angioedema (52.5%; 95%CI 42.3:62.5), urticaria (36.6%; 95%CI 27.8:46.8) or angioedema (10.9%; 95%CI 5.6:18.7). Beta-lactams (48.5%; 95%CI 38.5:58.7), fluoroquinolones (13.9%; 95%CI 7.8%:22.2%) and macrolides (7.9%; 95%CI 3.5:15.0) were specified as the main causative drugs. All patients during hospitalization (a mean of 8.2 days; SD=2.2; range 2-13 days) took at least 3 medicines (a mean of 5.4 medicines per patient; SD=1.2; range 3-12 medicines). The total number of identified DRPs was 400, a mean of 4.0 DRPs per patient (SD=1.8). The most frequently identified type of DRPs was inappropriate route of drug administration (25.0%; 95%CI 20.8:29.5). This was followed by duplicate prescriptions (23.5%; 95%CI 19.4:28.0) and insufficient frequency of drug administration (19.0%; 95%CI 15.3:23.2). Potential drug-drug interactions and inappropriate drug prescriptions each accounted for 16.0% (95% CI 12.6:20.0) of all DRPs. Comparing all above items in 2015, 2016 and 2017 showed no statistically significant changes (p>0.05).

Conclusions:

Antibiotic allergy is a common reason for admissions. The treatment of antibiotic allergy is associated with numerous DRPs. Our results could be useful for development of strategies for improving the safety and quality of pharmacotherapy.

Piperacillin-Tazobactam Allergies: An Exception to Usual Penicillin Allergy

Purpose

The majority of penicillin allergy labels are false, and skin tests (ST) have high negative predictive value (NPV) of up to 90%. Piperacillin-tazobactam (PT) allergy has been suspected to be an exception to this, but existing literature is scarce. We investigate the epidemiology, clinical characteristics, testing outcomes and predictive value of ST in patients referred for suspected PT allergies.

Methods

The records of all patients referred for suspected PT allergy testing and prescription rates of PT in all Hong Kong public hospitals (2015–2019) were analyzed.

Results

There was an increase in both PT prescriptions and number of newly reported PT allergies between 2015 and 2019. The majority (91.1%) of patients with suspected PT allergy had at least 1 underlying medical co-morbidity or immunosuppressant use leading to increased risk of infections. Thirty-six patients with suspected PT allergy completed ST. Two patients had positive ST, and 32/34 patients with negative ST underwent drug provocation testing (DPT). Nine of these patients were diagnosed with PT allergy based on positive DPT. Overall, 11/34 (32.4%) were diagnosed with PT allergy and the NPV of ST was 71.9%.

Conclusions

There is growing utilization of PT and corresponding cases of suspected allergies. The majority of suspected PT allergies had increased risk for recurrent infections. Unlike other penicillin allergy, there is a high rate of genuine PT allergy (up to 30%) and a poor NPV of ST (up to 70%). DPT remains the gold standard for accurate diagnosis, and all patients with a suspected allergy should undergo thorough allergy workup.

Outcomes of Infectious Endophthalmitis in Patients with Systemic Antibiotic Allergies to Penicillins, Cephalosporins, or Vancomycin

PURPOSE

The mainstay empiric treatments of bacterial endophthalmitis are intravitreal vancomycin and ceftazidime. In the United States, up to 10% of the general population has a reported penicillin (PCN) allergy. Despite low cross-reactivity between PCN and later-generation cephalosporins, some providers alter the intravitreal antibiotic choice for endophthalmitis because of concern for allergic reactions. We evaluated the management strategies of infectious endophthalmitis in the setting of self-reported systemic antibiotic allergies and the association with adverse reactions after standard intravitreal antibiotic administration.

DESIGN

Single-center, retrospective cohort study.

PARTICIPANTS

All patients with endophthalmitis between 2005 and 2019 and documented PCN, PCN-analog, cephalosporin, or vancomycin allergy who received intravitreal antibiotics on the basis of International Classification of Diseases 9th and 10th Revisions, and Current Procedural Terminology codes.

METHODS

Retrospective chart review.

MAIN OUTCOME MEASURES

Any allergic reaction after intravitreal injection, additional surgical interventions required for treatment, and visual function at last recorded visit.

RESULTS

Of the 65 patients included in this cohort, the most common causes of endophthalmitis were postcataract extraction surgery (n = 23, 35.4%) and postintravitreal injection (n = 11, 16.9%). All patients (65/65) received intravitreal vancomycin, and 81.5% (53/65) received intravitreal ceftazidime. Of the 53 patients who received intravitreal ceftazidime, 46 (86.8%) had allergies to PCNs alone, 5 (9.4%) had a cephalosporin allergy alone, and 2 (3.8%) had reported allergies to both PCN and cephalosporin antibiotics. Two patients (3.1%) with a documented vancomycin allergy received intravitreal vancomycin without complication. No patients exhibited any systemic or local allergic reactions or complications after intravitreal injection.

CONCLUSIONS

There were no documented allergic reactions in this cohort of patients with systemic antibiotic allergies who were treated for infectious endophthalmitis. Our findings are consistent with previous reports of a low allergic cross-reactivity between PCN and later-generation cephalosporins. Ophthalmologists should use evidence-based practices and a careful informed consent process when choosing intravitreal antibiotics for patients with specific antibiotic allergies. In the routine patient with suspected bacterial endophthalmitis, PCN allergy may not be an absolute contraindication to intravitreal cephalosporin use.

Psychological profiles of patients with suspected drug allergy

Background

Several studies demonstrate an important association between allergic diseases and patients' psychological characteristics.

Objective

To evaluate any differences in the psychological characteristics of patients studied for suspected drug allergy in comparison with healthy controls. A secondary aim was to assess differences between patients with confirmed versus excluded drug allergy, with respect to the clinical aspects.

Methods

The psychological characteristics of 115 consecutive patients >16 years-old, studied for suspected drug allergy were assessed. They were compared with healthy controls. Four validated questionnaires were used to evaluate anxiety, depression, alexithymia, and personality type.

Results

Eighty-eight patients completed the evaluation: 34 had confirmed drug allergy and 33 excluded. Forty-eight healthy subjects filled the 4 questionnaires. Increased neuroticism was associated with increased odds of belonging to the excluded drug allergy group (odds ratio [OR], 1.374; 95% confidence interval [CI], 1.173–1.609). Increased neuroticism (OR, 1.244; 95% CI, 1.065–1.453) and increased anxiety (OR, 1.210; 95% CI, 1.084–1.351) were associated with increased odds of confirmed drug allergy. However, higher extraversion decreased this likelihood (OR, 0.755; 95% CI, 0.643–0.888). The odds of having confirmed drug allergy was reduced by 79.7% (OR, 0.203; 95% CI, 0.060–0.694) for patients with 2 suspected drugs and by 84.6% (OR, 0.154; 95% CI, 0.029–0.809) for those with ≥3 in comparison to those with only one. Patients with moderate to severe reactions were more likely to have confirmed drug allergy (OR, 4.295; 95% CI, 1.105–16.693) than those with milder manifestations.

Conclusion

Our results highlight that patients with drug allergy have a distinctive psychological profile. Psychological assessment may help to identify patients that would benefit from a targeted intervention.

Practical guide for evaluation and management of beta-lactam allergy: position statement from the Canadian Society of Allergy and Clinical Immunology

The vast majority of individuals labelled as allergic are not deemed truly allergic upon appropriate assessment by an allergist. A label of beta-lactam allergy carries important risks for individual and public health. This article provides an overview of beta-lactam allergy, implications of erroneous beta-lactam allergy labels and the impact that can be provided by structured allergy assessment. We provide recommendations on how to stratify risk of beta-lactam allergy, beta lactam challenge protocols as well as management of patients at high risk of beta-lactam allergy.

Prevalence and Impact of Reported Drug Allergies among Rheumatology Patients

Background: Drug allergies (DA) are immunologically mediated adverse drug reactions and their manifestations depend on a variety of drug- and patient-specific factors. The dysregulated immune system underpinning rheumatological diseases may also lead to an increase in hypersensitivity reactions, including DA. The higher prevalence of reported DA, especially anti-microbials, also restricts the medication repertoire for these already immunocompromised patients. However, few studies have examined the prevalence and impact of reported DA in this group of patients. Methods: Patients with a diagnosis of rheumatoid arthritis (RA), spondyloarthritis (SpA), or systemic lupus erythematosus (SLE) were recruited from the rheumatology clinics in a tertiary referral hospital between 2018 and 2019. Prevalence and clinical outcomes of reported DA among different rheumatological diseases were calculated and compared to a cohort of hospitalized non-rheumatology patients within the same period. Results: A total of 6081 patients (2541 rheumatology patients: 1286 RA, 759 SpA, and 496 SLE; and 3540 controls) were included. DA was more frequently reported among rheumatology patients compared to controls (23.8% vs. 13.8%, p < 0.01). Antibiotics and non-steroidal anti-inflammatory drugs (NSAIDs) were the two most commonly reported categories of DA with a prevalence of 12.0% and 5.1%, respectively. Reported antibiotics allergies were more frequent in patients with RA (OR = 1.20, 95% CI = 1.02–1.62, p = 0.03) and SLE (OR = 4.69, 95% CI = 3.69–5.95, p < 0.01); and associated with increased infection-related admissions among rheumatology patients (OR = 1.79, 95% CI = 1.09–2.95, p = 0.02). Among the subgroup of patients referred for allergy testing, 85.7% of beta-lactam antibiotic allergy labels were found to be inaccurate and de-labelled after negative drug provocation testing. Conclusion: The prevalence of reported DA was significantly higher in rheumatology patients. Reported antibiotic allergy was associated with increased rate of infection-related admissions. However, the rate of genuine antibiotic allergy was low. Further studies are needed to guide proper assessment of reported DA and impact of comprehensive allergy testing in this group of patients.