Absence of cross-reactivity between sulfonamide antibiotics and sulfonamide nonantibiotics

The Pseudotumor Cerebri Syndrome

Pseudotumor cerebri syndrome is a syndrome of increased cerebrospinal fluid pressure without ventriculomegaly, mass lesion, or meningeal abnormality. It is either primary (idiopathic intracranial hypertension, IIH) or secondary. A secondary cause is unlikely when adhering to the diagnostic criteria. Permanent visual loss occurs if undetected or untreated, and the associated headaches may be debilitating. Fulminant disease may result in blindness despite aggressive treatment. This study addresses the diagnosis and management of IIH including new insights into the pathobiology of IIH, updates in therapeutics and causes of overdiagnosis.

Changing patterns in the epidemiology of drug allergy

Drug allergy (DA) remains a complex and unaddressed problem worldwide that often deprives patients of optimal medication choices and places them at risk for life-threatening reactions. Underdiagnosis and overdiagnosis are common and due to the lack of standardized definitions and biomarkers. The true burden of DA is unknown, and recent efforts in data gathering through electronic medical records are starting to provide emerging patterns around the world. Ten percent of the general population engaged in health care claim to have a DA, and the most common label is penicillin allergy. Up to 20% of emergency room visits for anaphylaxis are due to DA and 15%-20% of hospitalized patients report DA. It is estimated that DA will increase based on the availability and use of new and targeted antibiotics, vaccines, chemotherapies, biologicals, and small molecules, which are aimed at improving patient's options and quality of life. Global and regional variations in the prevalence of diseases such as human immunodeficiency virus and mycobacterial diseases, and the drugs used to treat these infections have an impact on DA. The aim of this review is to provide an update on the global impact of DA by presenting emerging data on drug epidemiology in adult and pediatric populations.

Immune-mediated polyarthritis and anterior uveitis secondary to zonisamide administration in a dog with refractory epilepsy

The objective of this article is to describe a case of suspected zonisamide-induced immune-mediated polyarthritis (IMPA) and anterior uveitis in a dog. A 7-year-old male neutered Siberian Husky with a history of refractory idiopathic epilepsy was presented for cluster seizures. Following the addition of zonisamide to the antiepileptic regime, the dog developed new IMPA and anterior uveitis. Within a few weeks of discontinuation of the zonisamide, the dog's IMPA and anterior uveitis resolved. These immune-mediated conditions were thus presumed to be an idiosyncratic reaction to zonisamide. To our knowledge, this is the first report of IMPA and anterior uveitis in dogs associated with zonisamide administration at its recommended dose.

Antibiotic prophylaxis in immunosuppressed patients - Missed opportunities from trimethoprim-sulfamethoxazole allergy label

Trimethoprim-sulfamethoxazole (TMP-SMX) is a broad spectrum antibiotic in use for more than 50 years. It has an important indication as first line agent in the prophylaxis of opportunistic infections, particularly Pneumocystis jirovecii pneumonia (PJP), in immunosuppressed patients. For those who have a history of allergy or severe intolerance to TMP-SMX, pentamidine, dapsone or atovaquone may be substituted; however there is evidence that TMP-SMX offers superior coverage for PJP, toxoplasmosis, and nocardiosis. Compared to pentamidine, it has the added benefit of cost-effectiveness and self-administration as opposed to required hospital attendance for administration. Many patients who report a history of allergy or adverse reaction to TMP-SMX (or "sulfur allergy") will be found not to be allergic; and even those who are allergic may be able to be desensitized. The evaluation and, where appropriate, removal of TMP-SMX allergy label enables the use of TMP-SMX for prophylaxis against opportunistic infections. This is a cost-effective intervention to optimize antimicrobial prescribing and reduce the risk of opportunistic infections in immunosuppressed patients.

Simultaneous hypersensitivity reactions to trimethoprim-sulfamethoxazole and amoxicillin-clavulanate in a dog

Antibiotics are known to be able to cause hypersensitivity reactions through various mechanisms. We present a case of drug-induced immune thrombocytopenia (DITP) and anaphylactic shock occurring simultaneously in a dog after the administration of two classes of antibiotics, namely trimethoprim-sulfamethoxazole (TMP-SMX) and amoxicillin-clavulanate (AMC). The patient recovered completely from DITP on discontinuation of TMP-SMX and the anaphylactic shock caused by AMC was treated with intensive care. DITP is a rare adverse drug reaction (ADR), and anaphylactic shock is a life-threatening ADR. This is the first case report of a dog manifesting two types of hypersensitivity reactions caused by two antibiotics.

Optimizing Cefazolin Prophylaxis in Obstetrical Patients with Reported Beta-Lactam Allergy Undergoing Cesarean Delivery

OBJECTIVE

Evaluate the impact of an allergy history guided algorithm for optimizing peri-operative cefazolin use in patients with reported beta-lactam allergy undergoing cesarean delivery.

METHODS

The Allergy Clarification for Cefazolin Evidence-based Prescribing Tool (ACCEPT) was developed through consensus by allergists, anesthesiologists and infectious diseases specialists, and implemented over a two-month period (December 1, 2018 to January 31, 2019). A segmented regression on monthly cefazolin use was conducted during the baseline (January 1 to November 30, 2018) and intervention (February 1 to December 31, 2019) periods to evaluate the impact of ACCEPT on the monthly use of peri-operative cefazolin in patients with reported beta-lactam allergy undergoing cesarean delivery. The frequency of peri-operative allergic reactions and surgical site infections were collected during both periods.

RESULTS

Of the 3128 eligible women who underwent a cesarean delivery, 282 (9%) reported a beta-lactam allergy. The most common beta-lactam allergens were penicillin (64.3%), amoxicillin (16.0%), and cefaclor (6.0%). The most frequently reported allergic reactions were rash (38.1%), hives (21.4%), and unknown (11.6%). Use of cefazolin increased from 52% (baseline) to 87% during the intervention period. Segmented regression analysis confirmed a statistically significant increase following implementation (incidence rate ratio 1.62, 95% CI 1.19 - 2.21, p=0.002). There was one perioperative allergic reaction in the baseline period and two during the intervention period. Cefazolin use remained high (92%) two years after algorithm implementation.

CONCLUSIONS

Implementation of a simple allergy history guided algorithm in obstetrical patients with reported beta-lactam allergy resulted in a sustained increase in peri-operative cefazolin prophylaxis.

Perioperative anaphylactic reactions to central venous and pulmonary artery catheters containing chlorhexidine, sulfadiazine, or latex: a historical cohort study

PURPOSE

Central venous catheters (CVCs) and pulmonary artery catheters (PACs) containing chlorhexidine, silver sulfadiazine, or latex can cause perioperative anaphylaxis. We examined the incidence of and outcomes associated with anaphylaxis caused by CVCs/PACs.

METHODS

In a historical cohort study, we retrospectively identified adult patients fitted with CVCs/PACs at the Mayo Clinics in Minnesota, Arizona, and Florida from 1 January 2008 to 1 March 2018. Potential and confirmed cases of perioperative anaphylactic reactions were individually reviewed and classified.

RESULTS

During the study period, 39,505 procedures were performed during which CVCs/PACs were inserted. Of these, 2,937 patients with pre-existing chlorhexidine, sulfonamide (sulfa), and/or latex allergies had CVCs/PACs inserted that contained these substances. Perioperative anaphylaxis, in which CVCs/PACs were the confirmed or potential causative agent, occurred during 53 procedures. Seven patients had a preoperatively reported sulfa or latex allergy; no patients had a preoperative chlorhexidine allergy. Six of the seven patients with reported allergies to sulfa or latex had a CVC/PAC inserted that contained these substances. Twenty-four patients with anaphylaxis had postoperative allergic disease consultation; ten of these (42%) underwent skin testing.

CONCLUSION

Perioperative anaphylactic reactions related to CVCs/PACs containing chlorhexidine, silver sulfadiazine, or latex were rare in this large historical cohort study. We identified 2,937 patients with pre-existing chlorhexidine, sulfa, and/or latex allergies and had CVCs/PACs inserted that contained these substances. Although few cases of perioperative anaphylaxis attributable to these substances were observed in patients with corresponding allergies, the potential for substantial complication exists. Providers should be aware of the potential for these hidden exposures.

The Use of Thiazide Diuretics for the Treatment of Hypertension in Patients With Advanced Chronic Kidney Disease

The use of thiazide diuretics for the treatment of hypertension in patients with advance chronic kidney disease. Thiazides have been recommended as the first-line for the treatment of hypertension, yet their use has been discouraged in advanced chronic kidney disease (CKD), as they are suggested to be ineffective in advanced CKD. Recent data suggest that thiazide diuretics may be beneficial blood pressure control in addition to natriuresis in existing CKD. This review discusses the commercially available thiazides with a focus on thiazide pharmacology, most common adverse effects, clinical uses of thiazide diuretic, and the evidence for efficacy of thiazide use in advanced CKD.

Pathophysiology of Acute Kidney Injury in Critical Illness: A Narrative Review

Acute kidney injury (AKI) is a syndrome that entails a rapid decline in kidney function with or without injury. The consequences of AKI among acutely ill patients are dire and lead to higher mortality, morbidity, and healthcare cost. To prevent AKI and its short and long-term repercussions, understanding its pathophysiology is essential. Depending on the baseline kidney histology and function reserves, the number of kidney insults, and the intensity of each insult, the clinical presentation of AKI may differ. While many factors are capable of inducing renal injury, they can be categorized into a few processes. The three primary processes reported in the literature are hemodynamic changes, inflammatory reactions, and nephrotoxicity. The majority of patients with AKI will suffer from more than one during their development and/or progression of AKI. Moreover, the development of one usually leads to the instigation of another. Thus, the interactions and progression between these mechanisms may determine the severity and duration of the AKI. Other factors such as organ crosstalk and how our concurrent therapies interact with these mechanisms complicate the pathophysiology of the progression of the AKI even further. In this narrative review article, we describe these three main pathophysiological processes that lead to the development and progression of AKI. © 2022 American Physiological Society. Compr Physiol 12: 1-14, 2022.

Reproducibility of real-world evidence studies using clinical practice data to inform regulatory and coverage decisions

Studies that generate real-world evidence on the effects of medical products through analysis of digital data collected in clinical practice provide key insights for regulators, payers, and other healthcare decision-makers. Ensuring reproducibility of such findings is fundamental to effective evidence-based decision-making. We reproduce results for 150 studies published in peer-reviewed journals using the same healthcare databases as original investigators and evaluate the completeness of reporting for 250. Original and reproduction effect sizes were positively correlated (Pearson’s correlation = 0.85), a strong relationship with some room for improvement. The median and interquartile range for the relative magnitude of effect (e.g., hazard ratio_original/hazard ratio_reproduction) is 1.0 [0.9, 1.1], range [0.3, 2.1]. While the majority of results are closely reproduced, a subset are not. The latter can be explained by incomplete reporting and updated data. Greater methodological transparency aligned with new guidance may further improve reproducibility and validity assessment, thus facilitating evidence-based decision-making. Study registration number: EUPAS19636.

Analyses of real-world evidence from digital clinical practice data provide important insights for healthcare decision makers. Here, authors test reproducibility of 150 peer-reviewed studies, reporting strong reproducibility, which could be further improved through more complete reporting in future original studies

CROSS-REACTIVITY TO ANTIBIOTICS: PROPOSITIONS FOR SELECTING ALTERNATIVES

OBJECTIVE

The aim: To analyze CR among antibacterials of different classes and to overcome some widespread misconceptions regarding CR between different classes of antibiotics.

PATIENTS AND METHODS

Materials and methods: The narrative review represents an assessment of the most pertinent literary sources published in English language, which dealt with the issues of cross-reactivity between individual antibiotics and different classes of these ones.

CONCLUSION

Conclusions: With a high probability of type I AR in a patient in the past, it is better to plan the treatment of patients together with an allergist / immunologist. If this probability is estimated to be low, the choice of a particular antibiotic may be based to some extent on CR data.

Standards for practical intravenous rapid drug desensitization & delabeling: A WAO committee statement

Drug hypersensitivity reactions (DHRs) to intravenous drugs can be severe and might leave patients and doctors in a difficult position where an essential treatment or intervention has to be suspended. Even if virtually any intravenous medication can potentially trigger a life-threatening DHR, chemotherapeutics, biologics, and antibiotics are amongst the intravenous drugs most frequently involved in these reactions. Admittedly, suspending such treatments may negatively impact the survival outcomes or the quality of life of affected patients.

Delabeling pathways and rapid drug desensitization (RDD) can help reactive patients stay on first-choice therapies instead of turning to less efficacious, less cost-effective, or more toxic alternatives. However, these are high-complexity and high-risk techniques, which usually need expert teams and allergy-specific techniques (skin testing, in vitro testing, drug provocation testing) to ensure safety, an accurate diagnosis, and personalized management. Unfortunately, there are significant inequalities within and among countries in access to allergy departments with the necessary expertise and resources to offer these techniques and tackle these DHRs optimally.

The main objective of this consensus document is to create a great benefit for patients worldwide by aiding allergists to expand the scope of their practice and support them with evidence, data, and experience from leading groups from around the globe.

This statement of the Drug Hypersensitivity Committee of the World Allergy Organization (WAO) aims to be a comprehensive practical guide on the technical aspects of implementing acute-onset intravenous hypersensitivity delabeling and RDD for a wide range of drugs. Thus, the manuscript does not only focus on clinical pathways. Instead, it also provides guidance on topics usually left unaddressed, namely, internal validation, continuous quality improvement, creating a healthy multidisciplinary environment, and redesigning care (including a specific supplemental section on a real-life example of how to design a dedicated space that can combine basic and complex diagnostic and therapeutic techniques in allergy).

Serious Adverse Events of Oral and Topical Carbonic Anhydrase Inhibitors

IMPORTANCE

Some ophthalmologists may be reluctant to prescribe oral carbonic anhydrase inhibitors, given the potential for life-threatening systemic adverse reactions.

OBJECTIVE

To conduct a population-based analysis of the safety of oral or topical carbonic anhydrase inhibitors in clinical care.

DESIGN, SETTING, AND PARTICIPANTS

This matched longitudinal cohort study took place in Ontario, Canada. Consecutive patients older than 65 years who were prescribed an oral or topical carbonic anhydrase inhibitor in Ontario, Canada, between January 1, 1995, and January 1, 2020, were identified. Patients were matched 1-to-1 based on age, sex, and diabetes status. Time zero was defined as the date of the first identified prescription for the medication, and the primary analysis focused on the first 120 days of follow-up.

MAIN OUTCOMES AND MEASURES

The primary end point was a severe complicated adverse event of either Stevens-Johnson syndrome, toxic epidermal necrolysis, or aplastic anemia.

RESULTS

Overall, 128 942 matched patients initiated an oral or topical carbonic anhydrase inhibitor during the 25-year study period. The mean (SD) age was 75 (6.6) years, 71 958 (55.8%) were women, and 25 058 (19.4%) had a diagnosis of diabetes. The oral and topical carbonic anhydrase inhibitor groups had similar baseline demographics. Patients prescribed an oral carbonic anhydrase inhibitor had an absolute risk of a severe complicated adverse event of 2.90 per 1000 patients, whereas patients prescribed a topical carbonic anhydrase inhibitor had an absolute risk of 2.08 per 1000 patients. This difference was equivalent to a risk ratio of 1.40, with a number needed to harm of 1 in 1220 patients (95% CI, 1.12-1.74; P = .003). This generally low risk was replicated in multivariable regression controlling for confounding factors. Additional risk factors for a severe complicated adverse event included patients with more comorbidities and those with more frequent clinic contacts.

CONCLUSIONS AND RELEVANCE

The risk of a serious adverse reaction following prescription of an oral or topical carbonic anhydrase inhibitor was low and similar between agents. Given the low risk of severe adverse reactions, this population-level analysis supports reconsidering the reluctance toward prescribing an oral carbonic anhydrase inhibitor.

Sulfonamide Hypersensitivity

Sulfonamides, particularly antimicrobial sulfonamides, have been implicated as a common cause of a spectrum of hypersensitivity reactions. Immediate IgE-mediated reactions have been reported but are much less common than delayed cutaneous reactions. Delayed cutaneous reactions range from benign exanthems to severe cutaneous reactions such as Stevens Johnson syndrome, toxic epidermal necrolysis, or drug reaction with eosinophilia and systemic symptoms. Sulfonamides can be subclassified as antimicrobial sulfonamides and non-antimicrobial sulfonamides, which are also distinguished by key structural differences, resulting in very low risk of cross-reactivity between these two subclasses. Immediate and delayed skin testing and in vitro testing remain limited as options in evaluating antimicrobial sulfonamide hypersensitivity. Drug challenges continue to play an important role in the evaluation of both immediate and delayed reactions, with a growing body of evidence for the safety of direct challenges regardless of human immunodeficiency virus infection status. While numerous "desensitization" protocols have been described for the management of antimicrobial sulfonamide hypersensitivity, there is limited evidence that such procedures are successful because of an induction of tolerance.

Delabeling Delayed Drug Hypersensitivity: How Far Can You Safely Go?

Delayed immune-mediated adverse drug reactions (IM-ADRs) are defined as reactions occurring more than 6 hours after dosing. They include heterogeneous clinical phenotypes that are typically T-cell-mediated reactions with distinct mechanisms across a wide spectrum of severity from benign exanthems through to life-threatening cutaneous or organ-specific diseases. For mild reactions such as benign exanthem, considerations for delabeling are similar to immediate reactions and may include a graded or single-dose drug challenge with or without preceding skin or patch testing. Evaluation of challenging cases such as the patient who is on multiple drugs at the time a severe delayed IM-ADR occurs should prioritize clinical ascertainment of the most likely phenotype and implicated drug(s). Although not widely available and validated, procedures such as patch testing, delayed intradermal skin testing, and laboratory-based functional drug assays or genetic (human leukocyte antigen) testing may provide valuable information to further help risk stratify patients and identify the likely implicated and/or cross-reactive drug(s). The decision to use a drug challenge as a diagnostic or delabeling tool in a patient with a severe delayed IM-ADR should weigh the risk-benefit ratio, balancing the severity and priority for the treatment of the underlying, and the availability of alternative efficacious and safe treatments.

Comparison of immediate hypersensitivity reactions to preoperative antibiotics in patients labeled as penicillin allergic

BACKGROUND

Cefazolin is routinely recommended as the first-line agent for surgical antibiotic prophylaxis because it prevents more surgical site infections than second-line antibiotics. Clinicians often avoid administering cefazolin to patients who are labeled as penicillin allergic due to concerns of cross-reactivity. The aim of this study was to compare the incidence of hypersensitivity reactions between cefazolin and the second-line antibiotics vancomycin and clindamycin.

METHODS

This retrospective study included patients who were labeled as penicillin allergic and received either cefazolin, clindamycin, or vancomycin as preoperative antibiotics. The primary outcome was intraoperative hypersensitivity reactions.

RESULTS

A total of 734 surgical procedures in 690 patients were included. Fifteen immediate hypersensitivity reactions were identified. Probable hypersensitivity reactions occurred in 3 (0.9%) patients in the cefazolin group, 4 (1.4%) in the clindamycin group, and 1 (1.1%) in the vancomycin group. Seven of 8 patients reported allergies to additional medications beyond penicillin. There were seven cases of possible hypersensitivity reactions, 3 (0.9%) in the cefazolin group, 1 (1.1%) in the vancomycin group, and 3 (1.0%) in the clindamycin group.

CONCLUSION

Our data suggest that perioperative hypersensitivity reactions are uncommon in patients labeled as penicillin allergic. The frequency of immediate hypersensitivity reactions was not different between patients receiving cefazolin, clindamycin, or vancomycin. Avoiding cefazolin in patients labeled as penicillin allergic may not be warranted.

Assessment of the Frequency of Dual Allergy to Penicillins and Cefazolin: A Systematic Review and Meta-analysis

Importance

Cefazolin is the preoperative antibiotic of choice because it is safer and more efficacious than second-line alternatives. Surgical patients labeled as having penicillin allergy are less likely to prophylactically receive cefazolin and more likely to receive clindamycin or vancomycin, which results in higher rates of surgical site infections.

Objective

To examine the incidence of dual allergy to cefazolin and natural penicillins.

Data Sources

MEDLINE/PubMed, Web of Science, and Embase were searched without language restrictions for relevant articles published from database inception until July 31, 2020.

Study Selection

In this systematic review and meta-analysis, a search of MEDLINE/PubMed, Web of Science, and Embase was performed for articles published from database inception to July 31, 2020, for studies that included patients who had index allergies to a natural penicillin and were tested for tolerability to cefazolin or that included patients who had index allergies to cefazolin and were tested for tolerability to a natural penicillin. A total of 3228 studies were identified and 2911 were screened for inclusion.

Data Extraction and Synthesis

Data were independently extracted by 2 authors. Bayesian meta-analysis was used to estimate the frequency of allergic reactions.

Main Outcomes and Measures

Dual allergy to cefazolin and a natural penicillin.

Results

Seventy-seven unique studies met the eligibility criteria, yielding 6147 patients. Cefazolin allergy was identified in 44 participants with a history of penicillin allergy, resulting in a dual allergy meta-analytical frequency of 0.7% (95% credible interval [CrI], 0.1%-1.7%; I2 = 74.9%). Such frequency was lower for participants with unconfirmed (0.6%; 95% CrI, 0.1%-1.3%; I2 = 54.3%) than for those with confirmed penicillin allergy (3.0%; 95% CrI, 0.01%-17.0%; I2 = 88.2%). Thirteen studies exclusively assessed surgical patients (n = 3884), among whom 0.7% (95% CrI, 0%-3.3%; I2 = 85.5%) had confirmed allergy to cefazolin. Low heterogeneity was observed for studies of patients with unconfirmed penicillin allergy who had been exposed to perioperative cefazolin (0.1%; 95% CrI, 0.1%-0.3%; I2 = 13.1%). Penicillin allergy was confirmed in 16 participants with a history of cefazolin allergy, resulting in a meta-analytical frequency of 3.7% (95% CrI, 0.03%-13.3%; I2 = 64.4%). The frequency of penicillin allergy was 4.4% (95% CrI, 0%-23.0%; I2 = 75%) for the 8 studies that exclusively assessed surgical patients allergic to cefazolin.

Conclusions and Relevance

These findings suggest that most patients with a penicillin allergy history may safely receive cefazolin. The exception is patients with confirmed penicillin allergy in whom additional care is warranted.

The use of acetazolamide for the prevention of high-altitude illness

BACKGROUND

Modern travel means that many travellers can arrive abruptly to high-altitude destinations without doing any trekking or climbing. Airports in high-altitude cities mean that travellers can go from sea level to over 3350-3960 m (11 000-13 000 feet) in a matter of hours, putting themselves at risk for high-altitude illness (HAI).

METHODS

Acetazolamide has been shown to be an effective way to help prevent HAI on such itineraries. The risk of HAI on rapid arrival to altitudes over 3350 m (11 000 feet) has been shown to range from 35% to nearly 50%. The risk can be higher for high-altitude trekking. This risk is far higher than most travel medicine risks and is on a par with the risk of travellers' diarrhea in high risk destinations.

RESULT

The use of prophylactic acetazolamide in a dosage of 125 mg every 12 h is highly effective at diminishing the risk of HAI.

CONCLUSION

Travel medicine practitioners should become comfortable with assessing the risk of HAI and determining when it is appropriate to offer acetazolamide prophylaxis to prevent HAI.

Genetic Association of Co-Trimoxazole-Induced Severe Cutaneous Adverse Reactions Is Phenotype-Specific: HLA Class I Genotypes and Haplotypes

Co-trimoxazole (CTX) causes various forms of severe cutaneous adverse reactions (SCARs). This case-control study was conducted to investigate the involvement between genetic variants of human leukocyte antigen (HLA) and CYP2C9 in CTX-induced SCARs, including Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN) and drug reaction with eosinophilia and systemic symptoms (DRESS) in Thai patients. Thirty cases of CTX-induced SCARs were enrolled and compared with 91 CTX-tolerant controls and 150 people from the general Thai population. Cases comprised 18 SJS/TEN and 12 DRESS patients. This study demonstrated that genetic association of CTX-induced SCARs was phenotype-specific. HLA-B*15:02 and HLA-C*08:01 alleles were significantly associated with CTX-induced SJS/TEN, whereas the HLA-B*13:01 allele was significantly associated with CTX-induced DRESS. In addition, a significant higher frequency of HLA-A*11:01-B*15:02 and HLA-B*13:01-C*03:04 haplotypes were detected in the group of CTX-induced Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) and DRESS cases, respectively. Genetic association of CTX-induced SCARs is phenotype-specific. Interestingly, these association was observed only in HIV-infected patients but not in non-HIV-infected patients.

Drugs frequently involved in inducing hypersensitivity reactions

Adverse drug reactions represent a major public health problem, both from an economic point of view and, mainly, from the point of view of the induced pathology (iatrogenic diseases), being difficult to differentiate from other pathological conditions or even from the treated disease. Thus, these aspects prevent the use of the first-choice drugs needed for a particular treatment, in different therapeutic classes: beta-lactam antibiotics; sulfonamides; macrolide antibiotics; quinolones; non-steroidal anti-inflammatories; corticosteroids; Angiotensin converting enzyme (ACE) inhibitors; general anesthetics; biological drugs; antiepileptic drugs etc. On the other hand, adverse drug reactions represent a major problem for both clinical practice and preclinical research, in order to develop new drugs. Hypersensitivity reactions mainly refer to the adverse effects that can be harmful, disturbing, and sometimes fatal, that appear under the conditions of a normal immune system, including allergies and autoimmune reactions, both triggered by an immunological-allergic mechanism. The main purpose of this paper is to review the main classes of drugs involved in inducing hypersensitivity reactions.

Non-β-Lactam Antibiotic Hypersensitivity Reactions

OBJECTIVES

Antibiotics are among the most common prescriptions in children, and non-β-lactam antibiotics (NBLAs) account for almost half of those prescribed in Australian pediatric hospitals. Despite this, data on NBLA hypersensitivity in children are limited. This study describes reported hypersensitivity reactions to NBLAs in children and the results of allergy evaluation.

METHODS

Children with a suspected NBLA allergy who had skin testing and/or an intravenous or oral challenge test (OCT) between May 2011 and June 2018 were included. Patients were excluded if they were >18 years old or did not complete the allergy evaluation for any reason other than allergic reaction.

RESULTS

Over the 7-year study period, 141 children had 150 allergy evaluations of 15 different NBLAs. The median time from the initial reported reaction to allergy evaluation was 1.9 (range 0.1-14.9) years. Overall, 27 of the 150 (18.0%) challenge tests to NBLAs had positive results, with the rate of positive OCT results being highest for trimethoprim-sulfamethoxazole (15 of 46; 32.6%) and macrolides (8 of 77; 10.4%). Although 4 children reported initial anaphylactic reactions, no patients had severe symptoms on rechallenge or required adrenaline. Of the challenges that had positive results, the majority of children (23 of 27; 85.2%) had symptoms on repeat challenge similar to those that were initially reported.

CONCLUSIONS

Overall, 8 of 10 children with NBLA allergy could be delabeled. On average, patients waited 1.9 years to be rechallenged. Timely access to allergy evaluation to delabel these patients is needed to preserve first-line antibiotics.

Sulfonamide desensitization in solid organ transplant recipients: A protocol-driven approach during the index transplant hospitalization

Trimethoprim-sulfamethoxazole (TMP-SMX) is the first-line agent for Pneumocystis jiroveci pneumonia (PJP) prophylaxis for solid organ transplant (SOT) recipients because of its efficacy for this indication, extended antimicrobial coverage, and favorable cost. Reported sulfonamide allergy is not uncommon and often results in TMP-SMX avoidance. Desensitization offers an efficacious and cost-effective alternative to TMP-SMX avoidance. Herein, we reviewed our experience with desensitization during the index transplant hospitalization among 52 SOT recipients with history of a non-anaphylactic sulfonamide allergy. Of those enrolled in the desensitization protocol, 92% (48/52) completed the protocol, with nearly 80% (41/52) still on TMP-SMX at 3 months without adverse reaction. Eleven patients discontinued TMP-SMX (7 for allergic reactions and 4 for non-allergic reasons) and switched to pentamidine. A cost savings of $575 per desensitization was calculated based on annual wholesale drug prices, for a total savings of $23 575. Additionally, the protocol did not delay discharge in any patient nor was it associated with any severe allergic reactions. These findings suggest TMP-SMX desensitization is safe and effective in SOT recipients with a history of non-anaphylactic, non-life-threatening sulfonamide hypersensitivity.

Contemporary management of the pseudotumor cerebri syndrome

Introduction: Diagnosis and appropriate management of patients with the pseudotumor cerebri syndrome are imperative to prevent or minimize permanent visual loss and headache-related disability. Areas covered: Steps in management, including making the correct diagnosis, techniques to assess the patient's visual status, medical treatment of intracranial hypertension and the associated headaches, weight management strategies, surgical treatments and stenting are reviewed incorporating the most recent medical evidence. Expert opinion: As the pathogenesis of the pseudotumor cerebri syndrome is still unknown, many of the currently employed management strategies incorporate a 'plumbing approach' to decrease cerebrospinal fluid (CSF) pressure. The Idiopathic Intracranial Hypertension Trial (IIHTT) taught us that the disorder markedly affects visual and overall quality of life, and that reducing pressure alone is not enough to make patients well, even those considered to have 'mild' vision loss. Other than the IIHTT, the evidence supporting the use of various treatments is meager. The course of the disorder can be unpredictable, and the clinician(s) managing these patients are often uncertain about which treatments to employ. Moreover, the desired modalities and specialists are not universally available in all locations. An individualized and detailed approach to the various manifestations and nuances of the disorder is essential.

Sulfonamide Allergies

As one of the earliest developed antimicrobial classes, sulfonamides remain important therapeutic options for the empiric and definitive treatment of various infectious diseases. In the general population, approximately 3–8% of patients are reported to experience a sulfonamide allergy. Sulfonamide allergies can result in various physical manifestations; however, rash is reported as the most frequently observed. In patients with human immunodeficiency virus (HIV), dermatologic reactions to sulfonamide antimicrobial agents occur 10 to 20 times more frequently compared to immunocompetent patients. This article describes the incidence, manifestations, and risk factors associated with sulfonamide allergies. The potential for cross-reactivity of allergies to sulfonamide antimicrobials with nonantimicrobial sulfonamide medications is also reviewed. Data suggest that substitutions at the N₁ and N₄ positions are the primary determinants of drug allergy instead of the common sulfonamide moiety. For patients with an indication for a sulfonamide antimicrobial with a listed allergy, it is important for healthcare practitioners to adequately assess the allergic reaction to determine appropriate management. Rechallenge and desensitization strategies may be appropriate for patients with delayed maculopapular eruptions, while alternative treatment options may be prudent for more severe reactions. Available data suggests a low risk of cross-allergenicity between sulfonamide antimicrobial and nonantimicrobial agents.

Cephalosporins: A Focus on Side Chains and β-Lactam Cross-Reactivity

Cephalosporins are among the most commonly prescribed antibiotic classes due to their wide clinical utility and general tolerability, with approximately 1–3% of the population reporting a cephalosporin allergy. However, clinicians may avoid the use of cephalosporins in patients with reported penicillin allergies despite the low potential for cross-reactivity. The misdiagnosis of β-lactam allergies and misunderstanding of cross-reactivity among β-lactams, including within the cephalosporin class, often leads to use of broader spectrum antibiotics with poor safety and efficacy profiles and represents a serious obstacle for antimicrobial stewardship. Risk factors for cephalosporin allergies are broad and include female sex, advanced age, and a history of another antibiotic or penicillin allergy; however, cephalosporins are readily tolerated even among individuals with true immediate-type allergies to penicillins. Cephalosporin cross-reactivity potential is related to the structural R1 side chain, and clinicians should be cognizant of R1 side chain similarities when prescribing alternate β-lactams in allergic individuals or when new cephalosporins are brought to market. Clinicians should consider the low likelihood of true cephalosporin allergy when clinically indicated. The purpose of this review is to provide an overview of the role of cephalosporins in clinical practice, and to highlight the incidence of, risk factors for, and cross-reactivity of cephalosporins with other antibiotics.

Beta-Lactam and Sulfonamide Allergy Testing Should Be a Standard of Care in Immunocompromised Hosts

Antibiotic allergies are reported in up to 1 in 4 immunocompromised hosts with significant impacts on antibiotic utilization and patient outcomes. Health services programs focused on de-labeling beta-lactam and sulfonamide allergy labels should be a standard of care in immunocompromised hosts.

Cyclo-oxygenase selectivity and chemical groups of nonsteroidal anti-inflammatory drugs and the frequency of reporting hypersensitivity reactions: a case/noncase study in VigiBase

To date, no reports of hypersensitivity reactions (HSRs) among nonsteroidal anti-inflammatory drugs (NSAIDs) according to cyclo-oxygenase (COX) selectivity and chemical groups have been published in a single study. The present study assessed the reporting frequency of HSRs for NSAIDs based on their relative inhibitory potency toward COX enzymes and chemical groups, including the presence/absence of a functional sulfonamide group, in strata observed 5 years after market authorization. A case/noncase study was performed among individual case safety reports (ICSRs) with NSAIDs as suspected drugs in VigiBase, the WHO spontaneous reporting database. Cases were ICSRs mentioning angioedema and anaphylactic/anaphylactoid shock conditions, while noncases were ICSRs without HSRs. NSAIDs were categorized into (i) NSAIDs with high COX-2 selectivity (coxibs), (ii) noncoxib NSAIDs with COX-2 preference, (iii) NSAIDs with poor selectivity, or (iv) NSAIDs with unknown selectivity. Chemical groups were defined based on the Anatomical Therapeutic Chemical classification system and the presence/absence of a functional sulfonamide group. Reporting odds ratios (RORs) and 95% confidence intervals (95% CIs) were calculated using logistic regression analysis. We identified 13 229 cases and 106 444 noncases. In the first 5 years after marketing, poor-selectivity NSAIDs and acetic acid derivatives were associated with the highest ROR of HSRs (age- and sex-adjusted ROR 2.12, 95% CI 1.98-2.28; and ROR 2.21, 95% CI 1.83-2.66, respectively) compared with coxibs, and sulfonamide NSAIDs were associated with the highest ROR of HSRs compared with nonsulfonamide NSAIDs (age- and sex-adjusted ROR 1.38, 95% CI 1.29-1.47). After the first 5 years of marketing, most of the RORs returned to approximately 1.

Antibiotic allergy

Antibiotics are the commonest cause of life-threatening immune-mediated drug reactions that are considered off-target, including anaphylaxis, and organ-specific and severe cutaneous adverse reactions. However, many antibiotic reactions documented as allergies were unknown or not remembered by the patient, cutaneous reactions unrelated to drug hypersensitivity, drug-infection interactions, or drug intolerances. Although such reactions pose negligible risk to patients, they currently represent a global threat to public health. Antibiotic allergy labels result in displacement of first-line therapies for antibiotic prophylaxis and treatment. A penicillin allergy label, in particular, is associated with increased use of broad-spectrum and non-β-lactam antibiotics, which results in increased adverse events and antibiotic resistance. Most patients labelled as allergic to penicillins are not allergic when appropriately stratified for risk, tested, and re-challenged. Given the public health importance of penicillin allergy, this Review provides a global update on antibiotic allergy epidemiology, classification, mechanisms, and management.

Drug Allergy

Drug allergy is commonly encountered in clinical practice. It is an immunological response to a pharmaceutical agent. The clinical presentation can vary from mild cutaneous reactions to life-threatening conditions such as Stevens-Johnson syndrome and toxic epidermal necrolysis. Diagnosis is most often clinical, but investigations such as measurement of immunoglobulin E, patch testing, and skin biopsy may be required. In patients with a known drug allergy, the offending drug should be avoided. [Pediatr Ann. 2018;47(10):e419-e425.].

Drug allergy

Drug allergy encompasses a spectrum of immunologically-mediated hypersensitivity reactions with varying mechanisms and clinical presentations. This type of adverse drug reaction not only affects patient quality of life, but may also lead to delayed treatment, unnecessary investigations, and even mortality. Given the myriad of symptoms associated with the condition, diagnosis is often challenging. Therefore, referral to an allergist experienced in the identification, diagnosis and management of drug allergy is recommended if a drug-induced allergic reaction is suspected. Diagnosis relies on a careful history and physical examination and, in some instances, skin testing and graded challenges. Induction of drug tolerance procedures may also be required. The most effective strategy for the management of drug allergy is avoidance or discontinuation of the offending drug. When available, alternative medications with unrelated chemical structures should be substituted. Cross-reactivity among drugs should be taken into consideration when choosing alternative agents. Additional therapy for drug hypersensitivity reactions is largely supportive and may include topical corticosteroids, oral antihistamines and, in severe cases, systemic corticosteroids. In the event of anaphylaxis, the treatment of choice is injectable epinephrine. If a particular drug to which the patient is allergic is indicated and there is no suitable alternative, induction of drug tolerance procedures may be considered to induce temporary tolerance to the drug. This article provides a background on drug allergy and strategies for the diagnosis and management of some of the most common drug-induced allergic reactions, such as penicillin, sulfonamides, cephalosporins, radiocontrast media, local anesthetics, general anesthetics, acetylsalicylic acid and non-steroidal anti-inflammatory drugs, and therapeutic monoclonal antibodies.

"Doctor, I have a Sulfa Allergy": Clarifying the Myths of Cross-Reactivity

Our purpose is to present an evidence-based approach, directed primarily towards eye-care specialists, clarifying whether certain drugs should or should not be used in patients with sulfonamide allergy. We conducted a literature search using PubMed to identify the risk of ophthalmic-specific drugs in patients with a self-reported sulfonamide allergy. MeSH key words included "sulfonamide" and "hypersensitivity". Articles specifically geared towards ophthalmic diseases were sought. The evidence illustrates that individuals with sulfonamide allergy are intrinsically predisposed to higher rates of allergic reaction that is not specific towards sulfonamide non-antimicrobials or sulfur-based medications. We provide a simplified algorithm using the 2017 Clinical Guide to Ophthalmic Drugs to help busy eye care clinicians determine whether a certain common ophthalmic medication is safe or unsafe to prescribe in a patient with a "sulfa allergy".

Sulfonamide Drug Allergy

PURPOSE OF REVIEW

We sought to review past and current literature on sulfonamide drug allergy and distill it in a practical manner to assist the clinician, specifically focusing on cross-reactivity and desensitization.

RECENT FINDINGS

There do not appear to be consistent genetic markers to reliably predict features of or the presence hypersensitivity reactions. Recent evidence continues to alleviate early concerns cross-reactivity between sulfonamide antibiotics and non-antibiotics. Sulfonamide drug allergy is frequently encountered by the practicing clinician. For sulfonamide antibiotics, delayed rash is the most common clinical manifestation. There is no current evidence to support avoidance of all non-antibiotic sulfonamides in those with a reported allergy to sulfonamide antibiotics, although certain scenarios require caution. Available evidence supports the cautious reintroduction of sulfonamide antibiotics via desensitization, which is usually well tolerated and should be considered in those with strong indications for trimethoprim-sulfamethoxazole and a reported sulfonamide allergy.

Antibiotic Allergy in Pediatrics

The overlabeling of pediatric antibiotic allergy represents a huge burden in society. Given that up to 10% of the US population is labeled as penicillin allergic, it can be estimated that at least 5 million children in this country are labeled with penicillin allergy. We now understand that most of the cutaneous symptoms that are interpreted as drug allergy are likely viral induced or due to a drug-virus interaction, and they usually do not represent a long-lasting, drug-specific, adaptive immune response to the antibiotic that a child received. Because most antibiotic allergy labels acquired in childhood are carried into adulthood, the overlabeling of antibiotic allergy is a liability that leads to unnecessary long-term health care risks, costs, and antibiotic resistance. Fortunately, awareness of this growing burden is increasing and leading to more emphasis on antibiotic allergy delabeling strategies in the adult population. There is growing literature that is used to support the safe and efficacious use of tools such as skin testing and drug challenge to evaluate and manage children with antibiotic allergy labels. In addition, there is an increasing understanding of antibiotic reactivity within classes and side-chain reactions. In summary, a better overall understanding of the current tools available for the diagnosis and management of adverse drug reactions is likely to change how pediatric primary care providers evaluate and treat patients with such diagnoses and prevent the unnecessary avoidance of antibiotics, particularly penicillins.

Taking the challenge: A protocolized approach to optimize Pneumocystis pneumonia prophylaxis in renal transplant recipients

While trimethoprim-sulfamethoxazole is considered first-line therapy for Pneumocystis pneumonia prevention in renal transplant recipients, reported adverse drug reactions may limit use and increase reliance on costly and less effective alternatives, often aerosolized pentamidine. We report our experience implementing a protocolized approach to trimethoprim-sulfamethoxazole adverse drug reaction assessment and rechallenge to optimize prophylaxis in this patient cohort. We retrospectively reviewed 119 patients receiving Pneumocystis pneumonia prophylaxis prior to and after protocol implementation. Forty-two patients (35%) had 48 trimethoprim-sulfamethoxazole adverse drug reactions documented either at baseline or during the prophylaxis period, of which 83% were non-immune-mediated and 17% were immune-mediated. Significantly more patients underwent trimethoprim-sulfamethoxazole rechallenge after protocol implementation (4/22 vs 23/27; P = .0001), with no recurrence of adverse drug reactions in 74%. In those who experienced a new or recurrent reaction (26%), all were mild and self-limiting with only 1 recurrence of an immune-mediated reaction. After protocol implementation, aerosolized pentamidine-associated costs were reduced. The introduction of a standard approach to trimethoprim-sulfamethoxazole rechallenge in the context of both prior immune and non-immune-mediated reactions was safe and successful in improving the uptake of first-line Pneumocystis pneumonia prophylaxis in renal transplant recipients.