Female sex as a risk factor for penicillin allergy

The role of major and minor determinants in penicillin allergy testing: Time to revisit an old friend?

Background

Skin testing is an important step in evaluation of penicillin allergic reactions. It includes testing to the following: amoxicillin, benzyl penicillin, and products generated in vivo after penicillin administration, the major determinant hapten penicilloyl-polylysine (PPL) and the minor determinant mixture (MDM). Although PPL and MDM are available as a commercial kit, their supply and cost remain problematic.

Objective

We aimed to evaluate the performance and utility of PPL and MDM in penicillin allergy testing.

Methods

A retrospective audit over a 5-year period was undertaken for those with penicillin testing in a tertiary immunology unit.

Results

In all, 214 patients were identified. Of those patients, 151 (70.6%) were female and the average age was 58 years. Unspecified penicillin was the most common index drug (n = 127 [59.3%]), followed by amoxicillin (n =3 [24.8%]) and amoxicillin-clavulanic acid (n = 21 [9.7%]). The result of skin testing was positive in 23 patients (10.7%); skin prick testing was positive in 10 patients (4.7%), and intradermal testing (IDT) was positive in 13 patients (6.1%), the majority of whom had identified amoxicillin or amoxicillin-clavulanic acid as the index drug (n = 22 [95.7%]). The result of testing to PPL and/or MDM was positive with IDT only (n=5 [23.8%]). PPL and MDM positivity coexisted with a positive reaction to amoxicillin IDT in 2 patients, 1 of whom passed an amoxicillin challenge. Additionally, 2 positive tests to PPL were present with a negative result for MDM; of these 2 positive results, 1 was positive to amoxicillin IDT. In only 1 case were the results of testing for MDM and PPL both positive, with negative results to all native β-lactams tested; the patient tolerated an amoxicillin challenge. Overall, the negative predictive value for both skin prick testing and IDT was 89.5%.

Conclusion

Benzyl penicillin and amoxicillin alone may be sufficient for in vivo testing in suspected individuals with penicillin allergy.

Drug Hypersensitivity Reactions in Patients with Cystic Fibrosis: Potential Value of the Lymphocyte Toxicity Assay to Assess Risk

BACKGROUND

Cystic fibrosis (CF) is a genetic disease characterized by multi-system dysfunction resulting in recurrent lung infections and progressive pulmonary disease. CF patients are at a higher risk for drug hypersensitivity reactions (DHRs) compared to the general population, which has been attributed to the recurrent need for antibiotics and the inflammation associated with CF disease. In vitro toxicity tests such as the lymphocyte toxicity assay (LTA) offer the potential for risk assessment for DHRs. In the current study, we investigated the utility of the LTA test for diagnosis of DHRs in a cohort of CF patients.

METHOD

Twenty CF patients with suspected DHRs to sulfamethoxazole, penicillins, cephalosporins, meropenem, vancomycin, rifampicin, and tobramycin were recruited to this study and tested using the LTA test along with 20 healthy control volunteers. Demographic data of the patients, including age, sex, and medical history, were obtained. Blood samples were withdrawn from patients and healthy volunteers, and the LTA test was performed on isolated peripheral blood monocytes (PBMCs) from those individuals.

RESULTS

Cells from CF patients with DHRs displayed a significant (p < 0.0001) concentration-dependent enhanced cell death upon incubation with the culprit drug compared to cells from healthy volunteers. The positivity rate of the LTA test was over 80% in patients with a medical history and clinical presentation consistent with DHRs.

CONCLUSION

This study is the first to evaluate the use of the LTA test for diagnosis of DHRs in CF patients. According to our results, the LTA test may be a useful tool for diagnosis and management of DHRs in CF patients. Identifying the culprit drug is essential for optimal healthcare for CF patients in the setting of a suspected DHR. The data also provide evidence that accumulation of toxic reactive metabolites could be an important component in the cascade of events leading to the development of DHRs in CF patients. A larger-scale study is needed to confirm the data.

The Dutch Working Party on Antibiotic Policy (SWAB) guideline for the approach to suspected antibiotic allergy

OBJECTIVES

Prudent handling of reported antibiotic allergy is an important aspect of antibiotic stewardship. The Dutch Working Party on Antibiotic Policy (SWAB) constituted a multidisciplinary expert committee to provide evidence-based recommendations for bedside decision making in antibiotic therapy in patients that report an antibiotic allergy.

METHODS

The guideline committee generated 12 key questions, most of which were population, intervention, comparison and outcome (PICO) questions relevant for both children and adults with suspected antibiotic allergy. For each question a systematic literature search was performed and reviewed for the best available evidence according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. Quality of evidence was graded from very low to high and recommendations were formulated in structured discussions as strong or weak.

RESULTS

Sixty recommendations were provided for suspected allergy to beta-lactam antibiotics (BLA) and non-beta-lactam antibiotics (NBLA). Due to the absence of randomized controlled trials in this field, the underlying evidence was predominantly graded as low or very low. Available data supports that a detailed allergy history should always be performed and critically appraised. When cross-allergy between BLA groups is not to be expected due to absence of molecular similarity of the side chains, the patient can be safely exposed to the alternative BLA. An exception to this rule are severe delayed type reactions, in which reexposure to a BLA should only be considered after consultation of a multidisciplinary team.

CONCLUSIONS

Accumulated scientific data now supports a more liberal approach that better balances benefits of treatment with first choice and usually smaller spectrum antibiotics with appropriate avoidance of antibiotics in case of a truly high risk of a (severe) allergic reaction. In the Netherlands, a formal guideline was developed that provides recommendations for the approach towards suspected allergy to BLA and frequently used NBLA, thereby strongly supporting antimicrobial stewardship.

Clavulanic Acid Is a Leading Culprit Beta-Lactam in Immediate Allergic Reactions to Penicillins

PURPOSE

Clavulanate, a beta-lactam associated with amoxicillin, is frequently prescribed in patients at all ages. Recent data implicate amoxicillin-clavulanate in up to 80% of beta-lactam allergy cases. We assessed clavulanate's role in inducing allergic reactions to this combination treatment, with a focus on selective immediate reactions.

METHODS

Adults (≥ 16 years) reporting a history of immediate reactions to amoxicillin-clavulanate were evaluated through a beta-lactam allergological workup, using modified European Academy of Allergy and Clinical Immunology guidelines. Patients first underwent skin testing, and if negative, drug provocation tests. Expected outcomes were: Group A, subjects with immediate reaction to classical penicillin group determinants (penicilloyl polylysine, minor determinants mixture, and/or penicillin G); Group B, subjects with selective immediate reaction to amoxicillin; Group C, subjects with selective immediate reaction to clavulanate and Group D, those immediate reactions with co-sensitization to clavulanate plus penicillin group determinants or amoxicillin.

RESULTS

Of 1,170 included patients, 104 had immediate reactions: 36.5% to penicillin group determinants (Group A), 26.9% to amoxicillin (Group B), 32.7% to clavulanate (Group C), and 3.8% to clavulanate plus penicillin determinants or amoxicillin (Group D). Diagnosis was made by skin testing in 79%, 75% and 47% of the patients, respectively, in the first 3 groups (P < 0.001). Drug provocation tests were necessary to establish most other diagnoses. Anaphylaxis predominated over urticaria/angioedema in all groups.

CONCLUSIONS

Selective immediate reactions to clavulanate accounted for over a third of cases with confirmed reactions after amoxicillin-clavulanate intake, with more than half experiencing anaphylaxis. Within this group, skin test sensitivity was below 50%. People taking amoxicillin-clavulanate may also be co-sensitized to both drugs.

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.

Cofactors of drug hypersensitivity-A monocenter retrospective analysis

Background

Drug hypersensitivity reactions (DHRs) are major medical problems that influence the treatment of patients by both under- and overdiagnosis. Still, little is known about the role of predisposing or protecting cofactors of DHR.

Objective

This study aims to determine drug-specific cofactors in patients with DHR.

Methods

Retrospective file chart analysis of inpatients with suspected DHR in our department between 2015 and 2020 was performed. Descriptive statistics and multiple logistic regression were conducted for the estimation and statistical interference.

Results

DHRs were suspected in 393 patients with 678 culprit drugs. In 183 cases, drug hypersensitivities were confirmed, mostly against nonopioid analgesic drugs and antibiotics. Multiple logistic regression analysis identified a positive association of antibiotic hypersensitivity with obesity [odds ratio (OR) 5.75, average marginal effect (AME) +24.4%] and age and a negative association with arterial hypertension, female sex, elevated immunoglobulin E (IgE), and allergic rhinitis. Hypersensitivity to nonopioid analgesics was associated with atopic dermatitis (OR 10.28, AME +28.5%), elevated IgE, and arterial hypertension.

Conclusions

Drug-specific cofactors of DHR include obesity for antibiotics and atopic dermatitis for nonopioid analgesics, the knowledge of which may improve the risk calculation for drug provocation tests.

Beta-lactam hypersensitivity in children: Frequency and risk factors

AIMS

To determine the frequency of an authentic β-lactam (BL) hypersensitivity (HS) amongst a large number of children and to identify clinical risk factors that predict this hypersensitivity.

METHODS

All children with suspected BL allergy were evaluated by skin tests (ST) with the suspected BL. A 1-day oral provocation test (OPT) was performed in children with negative ST. We defined an authentic BL-HS case if the child exhibited a positive ST or a positive OPT. Risk factors associated with BL-HS were assessed using a univariate analysis. Covariates showing a P-value <.2 were included in the multivariate logistic regression analysis to determine independent predictors.

RESULTS

A total of 354 patients reporting 368 suspected BL reactions were included. The diagnosis of BL-HS was established in 24 children (6.7%). All these children had a positive ST. OPT was performed in 30 patients and was negative in all of them. In 110 children with a negative ST, BL was tolerated. In the risk factors analysis, 164 children were included. Older age (>5 years) at the reaction (odds ratio = 1.11; 95% confidence interval, 1.01-1.22; P = .02) and BL administered (odds ratio = 7.7; 95% confidence interval, 2.76-21.8; P < .001) were significantly associated with authentic BL-HS.

CONCLUSION

BL-HS should be evaluated with an appropriate allergy work-up before strict prohibition is made. In addition, age of patient and BL involved can be used as predictive factors of developing BL-HS in this population.

Amoxicillin hypersensitivity: patient outcomes in a seven-year retrospective study

BACKGROUND

The beta-lactam antibiotic amoxicillin and the beta-lactamase inhibitor clavulanic acid in combination with amoxicillin are known to both cause immediate and non-immediate type hypersensitivity.

OBJECTIVE

To characterize a large cohort of patients with a history of amoxicillin or amoxicillin-clavulanic acid hypersensitivity.

METHODS

Retrospective analysis of demographics, presentation, investigation, and management of 331 patients presenting to one allergy center with a history of hypersensitivity to amoxicillin or amoxicillin-clavulanic acid.

RESULTS

Hypersensitivity was confirmed in 37/221 (17%) patients who took amoxicillin and 47/110 (43%) patients who took amoxicillin-clavulanic acid as the index drug. In immediate hypersensitivity, skin testing confirmed the diagnosis in 66/139 (47%) patients. Penicillin cross-reactivity was observed in 16/36 (44%). 13/16 (81%) cross-reactive patients reacted to amoxicillin-clavulanic acid as the index drug. All skin test negative patients (73/139) underwent drug provocation. The negative predictive value of skin tests was 89%. In non-immediate hypersensitivity, delayed intradermal tests confirmed diagnosis in 12/170 (7%). 8/12 (67%) skin test positive patients presented with DRESS. All skin test negative patients (158/170) underwent drug provocation. The negative predictive value of skin tests was 95%. Penicillin cross-reactivity was observed in 3/12 (25%). Ten patients were diagnosed with hypersensitivity to clavulanic acid.

CONCLUSION

The negative predictive value of skin tests in both immediate and non-immediate hypersensitivity reactions is excellent and excludes severe allergy. Non-immediate hypersensitivity is rare. Confirmed hypersensitivity is more likely if amoxicillin-clavulanic acid is the index drug. Cross-reactivity was more common in patients presenting with immediate hypersensitivity, most commonly involving benzylpenicillin. A minority of patients were allergic to clavulanic acid.

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.

De-labelling penicillin allergy in acutely hospitalized patients: a pilot study

Background

Penicillin allergy prevalence is internationally reported to be around 10%. However, the majority of patients who report a penicillin allergy do not have a clinically significant hypersensitivity. Few patients undergo evaluation, which leads to overuse of broad-spectrum antibiotics. The objective of this study was to monitor prevalence and implement screening and testing of hospitalized patients.

Methods

All patients admitted to the medical department in a local hospital in Oslo, Norway, with a self-reported penicillin allergy were screened using an interview algorithm to categorize the reported allergy as high-risk or low-risk. Patients with a history of low-risk allergy underwent a direct graded oral amoxicillin challenge to verify absence of a true IgE-type allergy.

Results

257 of 5529 inpatients (4.6%) reported a penicillin allergy. 191 (74%) of these patients underwent screening, of which 86 (45%) had an allergy categorized as low-risk. 54 (63%) of the low-risk patients consented to an oral test. 98% of these did not have an immediate reaction to the amoxicillin challenge, and their penicillin allergy label could thus be removed. 42% of the patients under treatment with antibiotics during inclusion could switch to treatment with penicillins immediately after testing, in line with the national recommendations for antibiotic use.

Conclusions

The prevalence of self-reported penicillin allergy was lower in this Norwegian population, than reported in other studies. Screening and testing of hospitalized patients with self-reported penicillin allergy is a feasible and easy measure to de-label a large proportion of patients, resulting in immediate clinical and environmental benefit. Our findings suggest that non-allergist physicians can safely undertake clinically impactful allergy evaluations.

Overview of Beta-Lactam Allergy and the Role of the Pharmacist in Management

Unverified beta-lactam allergies are a substantial public health problem, as the majority of patients labeled as beta-lactam allergic do not have clinically significant allergies that may hinder the use beta-lactam therapy when indicated. Outdated or inaccurate beta-lactam or penicillin allergies can result in serious consequences, including suboptimal antibiotic therapy, increased risk of adverse effects, and use of broader spectrum antibiotics than indicated, which may contribute to antimicrobial resistance. The purpose of this review is to provide an overview of beta-lactam allergy and highlight the role of pharmacists in managing beta-lactam allergies. Studies have shown that pharmacists can play a vital role in allergy assessment, penicillin skin testing, beta-lactam desensitization, evaluation of beta-lactam cross-reactivity and recommending appropriate antibiotic therapy in patients with beta-lactam allergies.

Characteristics of cutaneous adverse drug reactions caused by triple-combination drug therapy used for Helicobacter pylori eradication

Cutaneous adverse drug reactions (cADR) should be appropriately managed in drug administration. LANSAP® , Rabecure® and VONOSAP® are currently used for Helicobacter pylori eradication therapy. Here, we examined the characteristics of cADR caused by these drugs using data from the Pharmaceuticals and Medical Devices Agency (PMDA). Periods subject to analyses were set according to the year of release of these drugs: (i) from 2008 to 2017 for LANSAP; (ii) from 2014 to 2017 for Rabecure; and (iii) 2017 for VONOSAP. Among all cADR reported to the PMDA, those attributed to LANSAP, Rabecure and VONOSAP accounted for 2.3%, 1.0% and 3.6% of cases, respectively. cADR occurred in patients aged in their 20s or older, with the oldest patients aged in their 60s. Numbers of male and female patients were 28 and 70 for LANSAP, eight and 14 for Rabecure and three and 16 for VONOSAP, respectively. Statistical analyses revealed significant sex differences for LANSAP (P = 0.022) and VONOSAP (P = 0.012), but not for Rabecure (P = 0.729). LANSAP, Rabecure or VONOSAP caused erythema multiforme in the largest population of patients and Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) in three patients. Ratios of SJS/TEN were 0.0-5.3% for LANSAP, Rabecure or VONOSAP, but 11.5-44.8% for the corresponding single constituent drugs other than vonoprazan. In conclusion, female sex appears to represent a risk factor for cADR attributed to H. pylori eradication therapy using LANSAP or VONOSAP, although H. pylori eradication therapy without these drugs rarely causes severe cADR.

Minor Determinants of Penicillin and Amoxicillin Are Still Key Components of Penicillin Skin Testing

BACKGROUND

The positive rate and pattern of penicillin skin test (PST) has been reported to be decreasing and changing. Previous studies differ about which penicillin component is the dominant component in positive PST result.

OBJECTIVE

To characterize past and current PST patterns to determine whether different determinants in PST have changed over time.

METHODS

A retrospective review of electronic medical records (January 2001-December 2017) was performed for patients who underwent PST. Data were divided into 4 cohorts to see whether trends occurred over time. The cohorts were divided as follows: cohort 1 (2001-2005), cohort 2 (2006-2010), cohort 3 (2011-2015), and cohort 4 (2016-2017).

RESULTS

A total of 30,883 patients underwent PST with the following breakdowns per cohort: cohort 1, 6,536; cohort 2, 10,372; cohort 3, 10,640; and cohort 4, 3,335. Of these, 329 patients (1.0%) had a positive PST result with a wheal of 3 × 3 mm or greater, with 110 in cohort 1, 130 in cohort 2, 67 in cohort 3, and 22 in cohort 4, whereas 170 patients (0.5%) had a positive PST result with a wheal of 5 × 5 mm or greater, with 54 in cohort 1, 72 in cohort 2, 34 in cohort 3, and 10 in cohort 4. When the positive PST rates of cohort 2 (1.25%), cohort 3 (0.6%), and cohort 4 (0.6%) were compared with those of cohort 1 (1.7%), there was a significant decrease in positive PST rates (P = .0278; P < .0001; P < .0001, respectively). When cohort 1 positive rate to benzylpenicillin polylysine among the positive PST (wheal of 3 × 3 mm or greater) was compared with those of the other cohorts (cohorts 2-4), the percent positive of benzylpenicillin polylysine in PST was 27% compared with 21% (P = .38), 34% (P = .5), and 18% (P = .6), respectively. When the positive PST result was defined as a wheal of 5 × 5 mm or greater, the positive rate for benzylpenicillin polylysine in PST increased over time (cohort 2: 22%, P = .8; cohort 3: 32%, P = .3; cohort 4: 40%, P = .264) compared with cohort 1 (19%).

CONCLUSIONS

Positive PST rate is decreasing. We demonstrate that despite benzylpenicillin polylysine solely positive rates remaining relatively stable, the minor penicillin determinants and amoxicillin play an important role in PST and their adoption into standard protocol for routine PST should be considered.

The Basics of Penicillin Allergy: What A Clinician Should Know

Antimicrobials in the penicillin class are first line treatments for several infectious diseases in the pediatric and adult population today. In the United States, patients commonly report having a penicillin allergy, with penicillin being the most frequent beta-lactam allergy. However, very few patients experience a clinically significant immune-mediated allergic reaction to penicillin. If a true penicillin allergy exists, cross-reactivity to other beta-lactam antimicrobials may occur. Mislabeling patients with penicillin allergy can lead to a higher utilization of second line antimicrobial agents, potentially increasing costs and resistance due to a larger spectrum of activity. Pharmacists play an essential role in inquiring about patient specific reactions to presumed medication allergies and developing a further assessment plan, if needed, to determine if the medication allergy is real.

Flucloxacillin Hypersensitivity: Patient Outcomes in a Multicenter Retrospective Study

BACKGROUND

Flucloxacillin is a narrow-spectrum, beta-lactamase-resistant penicillin. Type I (IgE-mediated) and type IV (T-cell-mediated) reactions are less frequently reported than with other penicillins.

OBJECTIVE

To undertake a detailed clinical characterization of a cohort of patients referred with suspected flucloxacillin hypersensitivity.

METHODS

We retrospectively analyzed demographic characteristics, presentation, investigation, and management of 108 patients presenting to 4 UK centers. Patients underwent skin prick and intradermal testing with flucloxacillin, major (benzylpenicilloyl poly-l-lysine) and minor determinants, amoxicillin, and benzylpenicillin with immediate and, where appropriate, delayed reading of the test. In the immediate group, a further 14 patients were tested to ampicillin and 16 to Augmentin (co-amoxiclav-combination of clavulanic acid and amoxicillin). Skin test-negative patients underwent oral drug provocation. A multistep protocol was used, depending on risk assessment.

RESULTS

Forty of 108 (37%) patients were diagnosed with hypersensitivity to flucloxacillin, of whom 33 (82.5%) showed immediate and 7 (17.5%) nonimmediate hypersensitivity, respectively. In the immediate group, most reactions were severe: 19 of 33 (58%). Intradermal testing had a higher negative predictive value (86%) in the immediate group than in the nonimmediate group (67%). Only a minority of patients (6 of 17 [35%]) with IgE-mediated allergy were cross-sensitized on intradermal testing with other penicillins, compared with 3 of 4 (75%) in the delayed group.

CONCLUSIONS

Immediate hypersensitivity reactions to flucloxacillin are more common than delayed. Cross-sensitization to other penicillins appears higher in delayed reactions than in immediate. The negative predictive value of intradermal testing is higher in the immediate group than in the nonimmediate group. Drug provocation testing remains the diagnostic criterion standard.

Identifying Low-Risk Beta-Lactam Allergy Patients in a UK Tertiary Centre

BACKGROUND

There are marked geographical as well as temporal differences in patient sensitization profiles to β-lactams (BL).

OBJECTIVE

To determine the utility of skin test reagents and identify a cohort of patients where skin testing can be safely omitted in a cohort of patients referred to a UK tertiary referral center.

METHODS

A retrospective study of the clinical characteristics of 1092 patients referred for BL allergy testing was analyzed using multivariate regression analysis. The effectiveness of skin test reagents was also evaluated.

RESULTS

Multivariate logistic regression identified that a history of anaphylaxis (odds ratio [OR] 10.98, P = .001) and the patients' recall of the index drug (apart from ampicillin and meropenem, OR 3.51-12.43, P < .05) were independent predictors of type I BL allergic status and a time of less than 1 year elapsed since index reaction significantly increasing the odds of a patient with a history of anaphylaxis, having a type I BL allergy (OR 38.66, P = .003). An absence of anaphylactic severity, unknown name of the index drug and a reaction occurring more than 1 year before testing, has a negative predictive value (NPV) of 98.4%, which was similar to the NPV of skin testing of 98.9% for type I BL allergy. The NPV of skin testing with benzylpenicillin + amoxicillin ± index BL was similar with (98.9%) or without (98.1%) the use of benzylpenicillin polylysine and minor determinant for type I BL allergy.

CONCLUSION

We identified a "low risk" cohort of patients where the history is of similar reliability to skin testing in predicting nonallergic status for BL allergy.

Evaluating Penicillin Allergies Without Skin Testing

PURPOSE OF REVIEW

An unconfirmed penicillin allergy is known to confer significant risk to patients. Only a small minority of patients labeled with penicillin allergy will be confirmed to be hypersensitive with the current reference standard test, an oral amoxicillin therapeutic dose challenge. Skin testing has been recommended prior to oral challenges to reduce the risk of severe acute challenge reactions. The rate of severe acute anaphylactic reactions with oral amoxicillin is currently extremely low. Unfortunately, penicillin skin testing, as commonly performed, has a high rate of false positive results.

RECENT FINDINGS

Encouraging skin testing in all individuals with an unconfirmed penicillin allergy, prior to a confirmatory oral challenge, would be technically difficult, make testing all individuals with an unconfirmed penicillin allergy very unlikely, and ultimately increase the risk to patients because of suboptimal antibiotic use. Most patients, who are appropriate candidates for a direct oral amoxicillin challenge, to confirm current penicillin tolerance, can be safely identified by their clinical histories. Higher risk individuals, those with a history of anaphylaxis or other acute onset potentially IgE-mediated reaction such as hives within 6 h of the first dose of the last course of a penicillin, may benefit from properly performed puncture and intradermal skin testing, using commercially available penicilloyl-polylysine, prior to an oral challenge, if skin test negative. Direct oral amoxicillin challenges in low-risk individuals are well accepted by patients and a safe and effective part of penicillin allergy delabeling.

Penicillin Allergy Evaluation: A Prospective, Multicenter, Open-Label Evaluation of a Comprehensive Penicillin Skin Test Kit

BACKGROUND

Ten percent of the population claims an allergy to penicillin, but 90% of these individuals are not allergic. Patients labeled as penicillin-allergic have higher medical costs, longer hospital stays, are more likely to be treated with broad-spectrum antibiotics, and develop drug-resistant bacterial infections. Most penicillin skin test reagents are not approved by the Food and drug Administration or readily available to evaluate patients labeled penicillin-allergic.

OBJECTIVE

To determine the negative predictive value (NPV) of the Penicillin Skin Test Kit containing the major allergenic determinant (penicilloyl polylysine), a minor determinant mixture (penicillin G, penicilloate, penilloate), and amoxicillin, produced according to Food and Drug Administration standards.

METHODS

This was a prospective, multicenter, open-label investigation of penicillin skin testing using the Penicillin Skin Test Kit. Skin test-negative subjects were challenged with 250 mg amoxicillin, whereas skin test-positive patients were not challenged. The primary end point was NPV of the Penicillin Skin Test Kit, defined as the percentage of subjects with negative skin test results who did not experience an IgE-dependent reaction within 72 hours of amoxicillin challenge.

RESULTS

In total, 455 patients with a history of penicillin allergy underwent skin testing and 63 (13.8%) had 1 or more positive test results; 65% of the positive test results were to the minor determinant mixture and/or amoxicillin alone. In the per protocol group of 373 skin test-negative subjects, 8 developed potential IgE-dependent reactions following oral amoxicillin challenge, translating to an NPV of 97.9% (95% CI, 95.8-99.1; P < .0001). All but 1 of the reactions was mild or moderate, and most subjects who required treatment received only antihistamines.

CONCLUSIONS

The Penicillin Skin Test Kit, containing all relevant penicillin allergenic determinants, demonstrated very high NPV. Removal of a penicillin allergy label in a large majority of currently mislabeled patients has substantial personal and public health implications.

Drug Hypersensitivity Reactions Documented in Electronic Health Records within a Large Health System

BACKGROUND

Hypersensitivity reactions (HSRs) are immunologic responses to drugs. Identification of HSRs documented in the electronic health record (EHR) is important for patient safety.

OBJECTIVE

To examine HSR epidemiology using longitudinal EHR data from a large United States health care system.

METHODS

Patient demographic information and drug allergy data were obtained from the Partners Enterprise-wide Allergy Repository for 2 large tertiary care hospitals from 2000 to 2013. Drug-induced HSRs were categorized into immediate and delayed HSRs based on typical phenotypes. Causative drugs and drug groups were assessed. The prevalence of HSRs was determined, and sex and racial differences were analyzed.

RESULTS

Among 2.7 million patients, 377,474 (13.8%) reported drug-induced HSRs, of whom 70.3% were female and 77.5% were white. A total of 580,456 HSRs were reported, of which 53.1% were immediate reaction phenotypes. Common immediate HSRs included hives (48.8%), itching (15.0%), and angioedema (14.1%). Delayed HSR phenotypes (46.9%) were largely rash (99.0%). Penicillins were associated with the most immediate (33.0%) and delayed (39.0%) HSRs. Although most HSRs were more prevalent in females and white patients, notable differences were identified for certain rare HSRs including acute interstitial nephritis, which appeared more commonly in males (0.02% vs 0.01%, P < .001). Asian patients had more fixed drug eruptions (0.007% vs 0.002%, P = .021) and severe cutaneous adverse reactions (0.05% vs 0.04%, P < .001).

CONCLUSIONS

Drug HSRs were reported in 13.8% of patients. Almost one-half of reported immediate HSR phenotypes were hives, and almost all reported delayed HSR phenotypes were rash. HSRs largely affected female and white patients, but differences were identified for specific rare HSRs.

Drug allergy in children and adults: Is it the double X chromosome?

OBJECTIVE

This article reviews the latest science and epidemiologic studies related to drug allergy in children and adults to explore possible mechanisms related to female propensity for drug allergy.

DATA SOURCES

PubMed literature review, focusing primarily on the last 5 years.

STUDY SELECTIONS

Articles reviewing the science behind female predisposition to atopic and asthmatic conditions and epidemiologic studies reviewing drug allergy and drug-induced anaphylaxis.

RESULTS

Despite adult female predilection for atopic conditions, few laboratory studies explore sex-specific mechanisms in atopic/allergic diseases, and most are focused on autoimmunity and asthma. Drug allergy is more frequently reported in adult females compared with adult males. Adult females are also more likely to have drug-induced anaphylaxis (DIA), although no clear sex predominance has been reported in fatal or severe DIA. Studies in children suggest the reverse picture, with prepubertal males more likely to have drug allergy and DIA than prepubertal girls.

CONCLUSION

Possible explanations for female predisposition for drug allergy are multifactorial and include disproportionate utilization of health care with more exposure to antibiotics or medications, genetic factors related to the X chromosome, epigenetic changes, and discrepant hormonal interactions with immune cells.

Penicillin minor determinants: History and relevance for current diagnosis

OBJECTIVE

To review the history of the penicillin minor determinants and evaluate their relevance for current diagnosis.

DATA SOURCES

Skin testing to detect immunoglobulin E (IgE) sensitivity to penicillins in patients with a history of penicillin allergy has been the subject of more than 55 years of published research involving tens of thousands of patients.

STUDY SELECTIONS

Selection of data was based on its relevance to the objective of this article.

RESULTS

It was established early on that testing with the major penicilloyl determinant using the polyvalent penicilloyl-polylysine (PPL) is negative in a substantial portion (10% to 64%, including recent increases) of those at risk for immediate hypersensitivity reactions. A variety of minor penicillin determinants are clinically significant in that their use in skin testing is essential to detect all those at risk. In particular, a minor determinant mixture of benzylpenicillin, benzylpenicilloate, and benzylpenilloate, used in conjunction with PPL, has been shown in numerous studies to achieve an average negative predictive value (NPV) of 97.9% in history-positive patients. Benzylpenicillin alone, as the sole minor determinant, leaves many skin test-positive patients undiscovered. Use of amoxicillin as an additional minor determinant reagent appears to identify another 2% to 8% of skin test-positive patients in some populations.

CONCLUSION

IgE skin testing, using both the major and appropriate minor determinants of penicillin, can identify, with a high degree of reliability (NPV ∼97%), penicillin allergy history-positive patients who can receive beta-lactam antibiotics without concern for serious acute allergy, including anaphylaxis. The few false-negative skin tests reported globally are largely confined to minor, self-limited cutaneous reactions.

Antibiotic-Related Adverse Drug Reactions at a Tertiary Care Hospital in South Korea

Background

Adverse drug reactions (ADRs) are any unwanted/uncomfortable effects from medication resulting in physical, mental, and functional injuries. Antibiotics account for up to 40.9% of ADRs and are associated with several serious outcomes. However, few reports on ADRs have evaluated only antimicrobial agents. In this study, we investigated antibiotic-related ADRs at a tertiary care hospital in South Korea.

Methods

This is a retrospective cohort study that evaluated ADRs to antibiotics that were reported at a 2400-bed tertiary care hospital in 2015. ADRs reported by physicians, pharmacists, and nurses were reviewed. Clinical information reported ADRs, type of antibiotic, causality assessment, and complications were evaluated.

Results

1,277 (62.8%) patients were considered antibiotic-related ADRs based on the World Health Organization-Uppsala Monitoring Center criteria (certain, 2.2%; probable, 35.7%; and possible, 62.1%). Totally, 44 (3.4%) patients experienced serious ADRs. Penicillin and quinolones were the most common drugs reported to induce ADRs (both 16.0%), followed by third-generation cephalosporins (14.9%). The most frequently experienced side effects were skin manifestations (45.1%) followed by gastrointestinal disorders (32.6%).

Conclusion

Penicillin and quinolones are the most common causative antibiotics for ADRs and skin manifestations were the most frequently experienced symptom.

Penicillin and Beta-Lactam Hypersensitivity

Ten percent of patients report penicillin allergy, but more than 90% of these individuals can tolerate penicillins. Skin testing remains the optimal method for evaluation of possible IgE-mediated penicillin allergy and is recommended by professional societies, as the harms for alternative antibiotics include antimicrobial resistance, prolonged hospitalizations, readmissions, and increased costs. Removal of penicillin allergy leads to decreased utilization of broad-spectrum antibiotics, such as fluoroquinolones and vancomycin. There is minimal allergic cross-reactivity between penicillins and cephalosporins. IgE-mediated allergy to cephalosporins is usually side-chain specific and may warrant graded challenge with cephalosporins containing dissimilar R1 or R2 group side chains.

Utility of minor determinants for skin testing in inpatient penicillin allergy evaluation

BACKGROUND

Most patients with a history of penicillin allergy can tolerate penicillin. Skin testing can identify tolerant patients, but not all known allergenic determinants are commercially available. Protocols exist that use only available reagents, but the sensitivity and safety of these protocols, particularly for hospitalized patients, are controversial.

OBJECTIVE

To determine the number of hospitalized patients referred for penicillin skin testing who showed unique positivity to the minor determinants penicilloate and penilloate.

METHODS

A retrospective chart review was conducted of all inpatients who underwent penicillin skin testing at 1 institution. Patients were referred by their treating physician. All patients underwent skin prick testing to benzylpenicilloyl polylysine (major determinant), penicillin G, penicilloate, penilloate (minor determinants), amoxicillin, and positive and negative controls. If the result was negative, then intradermal testing was done with the same penicillin determinants and the negative control. A 4-mm wheal with flare was considered a positive reaction.

RESULTS

Inpatient penicillin skin testing was done in 528 subjects. Any positive test reaction was found in 107 subjects (20%). Three subjects (3%) reacted to penilloate only, 25 (23%) reacted to penicilloate only, 2 (2%) reacted to penicillin G only, and 8 (8%) reacted to amoxicillin only. Sixty-eight subjects (64%) reacted to a compound other than the major determinant.

CONCLUSION

This study found a high rate of exclusively positive skin test reactions to the minor determinants penicilloate and penilloate. Because patients with positive test reactions are at increased risk of reaction to drug challenge, these data support the use of these reagents for penicillin skin testing in hospitalized patients.

Penicillin allergy-getting the label right

Penicillinⁱ allergy is a potentially serious adverse reaction that impacts on antibacterial treatment options. Although it is commonly reported and recorded in medical records, only a minority of patients with a label of penicillin allergy actually have the condition confirmed. The term 'allergy' may be incorrectly applied to adverse reactions that do not have an immunological basis and inappropriate labelling of penicillin allergy can lead to the unnecessary avoidance of penicillins and other beta-lactam antibacterials. Here, we discuss key features that help to distinguish patients at low or high risk of having a true penicillin allergy, summarise what is known about the risk of allergic reactions to other beta-lactam antibacterials in patients with penicillin allergy and discuss the steps to consider when assessing a label of penicillin allergy.

Skin testing and drug challenge outcomes in antibiotic-allergic patients with immediate-type hypersensitivity

BACKGROUND

The evaluation of antibiotic immediate-type hypersensitivity is intricate because of nonstandardized skin testing and challenge method variability.

OBJECTIVE

To determine the safety outcomes and risk factors for antibiotic challenge reactions in patients reporting a history of antibiotic immediate-type hypersensitivity.

METHODS

A 5-year retrospective review of patients evaluated for immediate-type antibiotic allergy was conducted. Data analyzed included patient demographics, index reaction details, and outcomes of skin testing and challenges, classified as single-step or multistep.

RESULTS

Antibiotic hypersensitivity history was identified in 211 patients: 78% to penicillins, 10% to fluoroquinolones, 7.6% to cephalosporins, and 3.8% to carbapenems. In total, 179 patients completed the challenges (median age 67 years, range 50-76 years, 56% women), and compared with nonchallenged patients, they reported nonanaphylactic (P < .001) and remote index (P = .003) reactions. Sixteen patients (8.9%) experienced challenge reactions (5 of 28 for single-step challenge, 11 of 151 for multistep challenge), and 11 of these patients had negative skin testing results before the challenge. Challenge-reactive patients were significantly younger (P = .007), more often women (P = .036), and had additional reported antibiotic allergies (P = .005). No correlation was detected between the reported index and observed challenge reaction severities (κ = -0.05, 95% confidence interval -0.34 to 0.24). Anaphylactic rates were similar during single-step and multistep challenges (3.6% vs 3.3%).

CONCLUSION

In the present population, younger women with multiple reported antibiotic allergies were at greatest risk for challenge reactions. Negative skin testing results did not exclude reactions, and index severity was not predictive of challenge outcome. The multistep and full-dose methods demonstrated a comparable reaction risk for anaphylaxis.

Drug allergies documented in electronic health records of a large healthcare system

BACKGROUND

The prevalence of drug allergies documented in electronic health records (EHRs) of large patient populations is understudied.

OBJECTIVE

We aimed to describe the prevalence of common drug allergies and patient characteristics documented in EHRs of a large healthcare network over the last two decades.

METHODS

Drug allergy data were obtained from EHRs of patients who visited two large tertiary care hospitals in Boston from 1990 to 2013. The prevalence of each drug and drug class was calculated and compared by sex and race/ethnicity. The number of allergies per patient was calculated and the frequency of patients having 1, 2, 3…, or 10+ drug allergies was reported. We also conducted a trend analysis by comparing the proportion of each allergy to the total number of drug allergies over time.

RESULTS

Among 1 766 328 patients, 35.5% of patients had at least one reported drug allergy with an average of 1.95 drug allergies per patient. The most commonly reported drug allergies in this population were to penicillins (12.8%), sulfonamide antibiotics (7.4%), opiates (6.8%), and nonsteroidal anti-inflammatory drugs (NSAIDs) (3.5%). The relative proportion of allergies to angiotensin-converting enzyme (ACE) inhibitors and HMG CoA reductase inhibitors (statins) have more than doubled since early 2000s. Drug allergies were most prevalent among females and white patients except for NSAIDs, ACE inhibitors, and thiazide diuretics, which were more prevalent in black patients.

CONCLUSION

Females and white patients may be more likely to experience a reaction from common medications. An increase in reported allergies to ACE inhibitors and statins is noteworthy.

Penicillin allergy: optimizing diagnostic protocols, public health implications, and future research needs

PURPOSE OF REVIEW

Unverified penicillin allergy is being increasingly recognized as a public health concern. The ideal protocol for verifying true clinically significant IgE-mediated penicillin allergy needs to use only commercially available materials, be well tolerated and easy to perform in both the inpatient and outpatient settings, and minimize false-positive determinations. This review concentrates on articles published in 2013 and 2014 that present new data relating to the diagnosis and management of penicillin allergy.

RECENT FINDINGS

Penicillin allergy can be safely evaluated at this time, in patients with an appropriate clinical history of penicillin allergy, using only penicilloyl-poly-lysine and native penicillin G as skin test reagents, if an oral challenge with amoxicillin 250 mg, followed by 1 h of observation, is given to all skin test negative individuals.

SUMMARY

Millions of individuals falsely labeled with penicillin allergy need to be evaluated to safely allow them to use penicillin-class antibiotics and avoid morbidity associated with penicillin avoidance. Further research is needed to determine optimal protocol(s). There will still be a 1-2% rate of adverse reactions reported with all future therapeutic penicillin-class antibiotic use, even with optimal methods used to determine acute penicillin tolerance. Only a small minority of these new reactions will be IgE-mediated.

Management of allergy to penicillins and other beta-lactams

The Standards of Care Committee of the British Society for Allergy and Clinical Immunology (BSACI) and an expert panel have prepared this guidance for the management of immediate and non-immediate allergic reactions to penicillins and other beta-lactams. The guideline is intended for UK specialists in both adult and paediatric allergy and for other clinicians practising allergy in secondary and tertiary care. The recommendations are evidence based, but where evidence is lacking, the panel reached consensus. During the development of the guideline, all BSACI members were consulted using a Web-based process and all comments carefully considered. Included in the guideline are epidemiology of allergic reactions to beta-lactams, molecular structure, formulations available in the UK and a description of known beta-lactam antigenic determinants. Sections on the value and limitations of clinical history, skin testing and laboratory investigations for both penicillins and cephalosporins are included. Cross-reactivity between penicillins and cephalosporins is discussed in detail. Recommendations on oral provocation and desensitization procedures have been made. Guidance for beta-lactam allergy in children is given in a separate section. An algorithm to help the clinician in the diagnosis of patients with a history of penicillin allergy has also been included.

Penicillin skin testing is a safe and effective tool for evaluating penicillin allergy in the pediatric population

BACKGROUND

Penicillin skin testing has been validated in the evaluation of adult patients with penicillin allergy. However, the commercially available benzylpenicilloyl polylysine (Pre-Pen) is not indicated in the pediatric population. Moreover, the safety and validity of penicillin skin testing in the pediatric population has not been well studied.

OBJECTIVE

We describe the safety and validity of penicillin skin testing in the evaluation of children with a history of penicillin allergy.

METHODS

Children (<18 years) with a history of penicillin allergy were evaluated with penicillin skin tests and were reviewed for basic demographics, penicillin skin test results, adverse drug reaction to penicillin after penicillin skin test, and adverse reaction to penicillin skin test. By using the χ(2) test, we compared the differences in the proportion of children and adults with a positive penicillin skin test. P value (<.05) was considered statistically significant. The institutional review board approved the study, and all the subjects signed written informed consents.

RESULTS

A total of 778 children underwent penicillin skin testing; 703 of 778 patients had a negative penicillin skin test (90.4%), 66 had a positive test (8.5%), and 9 had an equivocal test (1.1%). Children were more likely to have a positive penicillin skin test (P < .0001) compared with adults (64 of 1759 [3.6%]); 369 of 703 patients with negative penicillin skin test (52%) were challenged with penicillin, and 14 of 369 patients (3.8%) had an adverse drug reaction. No adverse reactions to penicillin skin testing were observed.

CONCLUSION

Penicillin skin testing was safe and effective in the evaluation of children with a history of penicillin allergy.

Penicillin and beta-lactam allergy: epidemiology and diagnosis

Penicillin is the most common beta-lactam antibiotic allergy and the most common drug class allergy, reported in about 8% of individuals using health care in the USA. Only about 1% of individuals using health care in the USA have a cephalosporin allergy noted in their medical record, and other specific non-penicillin, non-cephalosporin beta-lactam allergies are even rarer. Most reported penicillin allergy is not associated with clinically significant IgE-mediated reactions after penicillin rechallenge. Un-verified penicillin allergy is a significant and growing public health problem. Clinically significant IgE-mediated penicillin allergy can be safely confirmed or refuted using skin testing with penicilloyl-poly-lysine and native penicillin G and, if skin test is negative, an oral amoxicillin challenge. Acute tolerance of an oral therapeutic dose of a penicillin class antibiotic is the current gold standard test for a lack of clinically significant IgE-mediated penicillin allergy. Cephalosporins and other non-penicillin beta-lactams are widely, safely, and appropriately used in individuals, even with confirmed penicillin allergy. There is little, if any, clinically significant immunologic cross-reactivity between penicillins and other beta-lactams. Routine cephalosporin skin testing should be restricted to research settings. It is rarely needed clinically to safely manage patients and has unclear predictive value at this time. The use of alternative cephalosporins, with different side chains, is acceptable in the setting of a specific cephalosporin allergy. Carbapenems and monobactams are also safely used in individuals with confirmed penicillin allergy. A certain predictable, but low, rate of adverse reactions will occur with all beta-lactam antibiotic use both pre- and post-beta-lactam allergy evaluations.

Evaluation of antibiotic allergy: the role of skin tests and drug challenges

Antibiotic allergies are frequently reported in both adult and pediatric populations. While a detailed drug history is essential in the evaluation of antibiotic allergy, the history is typically insufficient to determine the presence of a drug allergy. The most readily available diagnostic testing for evaluating antibiotic allergies are drug skin testing and drug challenges. This review will focus on updates in the evaluation of antibiotic allergy utilizing immediate skin tests, delayed intradermal testing, drug patch tests, and drug challenges for both adults and children with histories of antibiotic allergies.

Penicillin skin testing in cardiac surgery

BACKGROUND

Penicillin is the most commonly reported allergy in cardiac surgical patients and a history of penicillin allergy frequently results in the use of vancomycin for antibiotic prophylaxis. However, clinical history is unreliable and true allergy is rare. Penicillin allergy testing has the potential to reduce vancomycin use and indirectly the potential for selection of vancomycin-resistant organisms, a national priority.

METHODS

After the publication of the 2007 Society of Thoracic Surgeons practice guideline report, we initiated a penicillin allergy testing service for cardiac surgical patients in 2009. We sought to determine the true incidence of penicillin allergy in the tested population, whether testing availability reduced vancomycin use in those tested, and if vancomycin use was reduced in the entire cardiac surgical population as a whole.

RESULTS

A total of 276 patients were skin tested for allergy to penicillin or cephalosporin. Testing recommended no penicillin use in 13.8% of those tested giving a true penicillin allergy incidence of 0.9%. Only 24 of the 276 patients tested (9%) received vancomycin. However, given the small percentage of the total population that underwent allergy testing, the overall use of vancomycin in the cardiac surgery practice was not reduced in the posttesting period.

CONCLUSIONS

The true rate of contraindication to penicillin in a cardiac surgical population is very low. Penicillin allergy testing can reduce vancomycin use in the tested population, but better means of conducting the testing and making the results available are necessary to reduce unnecessary vancomycin use in a broader cardiac surgical population.

β-lactam allergy: clinical implications and costs

Background

β-lactam allergy is the most commonly reported medication allergy and it remains a key issue in antibiotic prescribing. A detailed and accurate history taking play a key role in preventing potentially serious clinical incidents and it may contribute in reducing costs.

Methods

Data were collected for patients with a documented penicillin allergy on their drug chart during a six month period. Sources included the inpatient drug charts and medical notes. Adherence to hospital guidelines was audited and costs of treatments were calculated.

Results

94 patients with a history of penicillin allergy were included. Compliance with the hospital antibiotic policy was 81% and 52% of cases had a description of the reaction documented. The mean additional cost per patient was £89.29 (excluding VAT).

Conclusions

It is important to maintain a high level of vigilance and constantly educate all healthcare professionals involved in prescribing and dispensing antibiotics in order to avoid the unnecessary use of non-penicillin-based antibiotics and associated cost implication.

Safely diagnosing clinically significant penicillin allergy using only penicilloyl-poly-lysine, penicillin, and oral amoxicillin

BACKGROUND

Penicillin skin testing is rarely used to undiagnose penicillin "allergy" in the United States, partially because of concern that commercially available materials are inadequate.

OBJECTIVE

We determined whether skin testing with only commercially available penicilloyl-poly-lysine and penicillin followed by an oral amoxicillin challenge, if skin test-negative, can safely identify clinically significant penicillin allergy.

METHODS

Five hundred sequential persons with positive history of penicillin "allergy" were evaluated by skin testing with penicilloyl-poly-lysine and penicillin between June 8, 2010, and March 29, 2012. All persons with negative skin tests were given an oral amoxicillin challenge and observed for 1 hour.

RESULTS

Persons undergoing penicillin allergy testing were representative of all health plan members with penicillin allergy. Only 4 persons (0.8%; 95% CI, 0.32%-2.03%) had a positive skin test result. Only 4 persons (0.8%; 95% CI, 0.32%-2.03%) had an acute objective oral amoxicillin challenge reaction. Fifteen persons (3.0%; 95% CI, 1.83%-4.98%) had subjective oral challenge reactions, either acute transient itching or dizziness. All were women and 11 (73.3%) had multiple drug intolerance syndrome. None had severe reactions or objective signs. These were not considered to be positive challenge reactions. Sixty-eight subjects (13.6%) who were negative on testing were exposed to 88 courses of penicillins during 90 days of follow-up. New reactions were reported after 4 courses (4.5%), 3 (75%) occurring in subjects with multiple drug intolerance syndrome.

CONCLUSIONS

Penicillin skin testing, using only penicilloyl-poly-lysine and penicillin, followed by oral amoxicillin challenge, if negative, can safely identify clinically significant IgE-mediated penicillin allergy in patients who use health care in the United States at this time.

Adverse reactions associated with therapeutic antibiotic use after penicillin skin testing

BACKGROUND

There is little prospective data on the antibiotics prescribed and the adverse reactions associated with their use after penicillin skin testing.

OBJECTIVE

Provide data on antibiotic use and new antibiotic "allergy" incidence after penicillin skin testing.

METHODS

All patients who had penicillin skin testing at our Medical Center between 1-1-2000 and 12-31-2004 were followed through 12-31-2009. All therapeutic antibiotic use and all new "allergies" listed in their electronic medical records were reviewed.

RESULTS

There were 1684 study subjects of whom 1191 (70.7%) were female. There were 118 (7.0%) positive to at least one penicillin skin test reagent and 3 (0.2%) were positive only to amoxicillin. The mean follow-up period was 4.5 ± 2.9 years. Subjects were exposed to a mean of 8.2 ± 10.5 therapeutic antibiotic courses during follow-up. The highest new antibiotic "allergy" incidence rates in skin test-negative subjects were noted for penicillins, 2.9%, and sulfonamides, 2.7%, p = 0.9097. Females had higher overall incidences of new antibiotic "allergy," independent of skin test result. Penicillin skin test-negative females treated with penicillin had a nonsignificantly higher new penicillin "allergy" incidence, 3.3% per course versus 1.9% for males, p = 0.0644. Cephalosporins had new antibiotic "allergy" incidence rates not significantly different from tetracyclines, quinolones, macrolides, clindamycin, metronidazole, nitrofurantoin, and other antibiotics.

CONCLUSIONS

Females had higher new antibiotic "allergy" incidence rates. New "allergy" to cephalosporins occurred no more frequently than with non-beta-lactam-antibiotics, independent of skin test result. Sulfonamide antibiotics were associated with the higher rates of new antibiotic "allergy" than cephalosporins.

The falling rate of positive penicillin skin tests from 1995 to 2007

BACKGROUND

Data on the rate of positive penicillin skin test (PenST) results over time in large populations are rare. The factors that influence positive PenST results are incompletely understood.

OBJECTIVES

We sought to correlate demographic variables to the rate of positive PenST results over time in a large group of patients with a history of penicillin allergy.

METHODS

RESULTS from the first test for all patients tested for penicillin allergy in the Kaiser Permanente Health Care Program in San Diego County, CA, between 1995 and 2007 are reported. All patients were tested with penicillin, penicilloyl-poly-lysine, penilloate, penicilloate, and amoxicillin.

RESULTS

There were 255 positive PenST results in 3469 individuals. The rate of positive PenST results declined from >10% to <5% during the 13 years studied. The positive PenST result rate could be accounted for by the year of testing (R(2) = 0.56; p = 0.003) without any significant contribution from the patient's age or the time since reaction (TSR). If the TSR was ≤13 years, the relative risk of a positive PenST result was 2.1 (95% confidence interval = 1.6-2.8). If the study subject's age was ≤38 years, the relative risk of a positive PenST result was 2.1 (95% confidence interval = 1.6-2.7). Females reported higher rates of penicillin allergy history than males did (11% compared with 6.6%; p < 0.0001), but there were no significant sex differences in the rate of positive PenST results.

CONCLUSIONS

There has been a steady decline in the proportion of positive PenST results between 1995 and 2007, independent of study subject age and TSR. Increasing age and increasing TSR were associated with a lower rate of positive PenST results.

Gender-specific asthma treatment

Because genetic characteristics vary among subjects, the therapeutic effects of a certain drug differ among patients with the same disease. For this reason, special interest has focused on tailored treatments. Although it is well known that sex is genetically determined, little attention has been paid to sex differences in the clinical features and treatment of asthma. Females are more likely to suffer allergic asthma, to have difficulty controlling asthma symptoms, and to show adverse effects to drugs. As asthma symptoms show cyclic changes depending on female hormone levels in many women of child-bearing age, the use of contraceptives may specifically help to treat female patients with asthma such as those with perimenstrual asthma and severe asthma. Generally, testosterone seems to suppress asthma, and dehydroepiandrosterone (DHEA), a less virilizing androgen, may be effective for treating asthma. Evidence exists for a therapeutic and steroid-sparing effect of DHEA. However, further studies on the optimal dose and route of DHEA for each sex are needed. Monitoring of the serum DHEA-S level is necessary for patients with asthma on inhaled steroid treatment, and at minimum, replacement therapy for patients with a low level of DHEA may be helpful for treating their asthma.