Is a positive intracutaneous test induced by penicillin mediated by histamine? A cutaneous microdialysis study in penicillin-allergic patients

Accuracy of penicillin allergy diagnostic tests: A systematic review and meta-analysis

BACKGROUND

Having a penicillin allergy label associates with a higher risk for antibiotic resistance and increased health care use.

OBJECTIVE

We sought to assess the accuracy of skin tests and specific IgE quantification in the diagnostic evaluation of patients reporting a penicillin/β-lactam allergy.

METHODS

We performed a systematic review and diagnostic accuracy meta-analysis, searching on MEDLINE, Scopus, and Web of Science. We included studies conducted in patients reporting a penicillin allergy and in whom skin tests and/or specific IgE quantification were performed and compared with drug challenge results. We quantitatively assessed the accuracy of diagnostic tests with bivariate random-effects meta-analyses. Meta-regression and subgroup analyses were performed to explore causes of heterogeneity. Studies' quality was evaluated using QUADAS-2 criteria.

RESULTS

We included 105 primary studies, assessing 31,761 participants. Twenty-seven studies were assessed by bivariate meta-analysis. Skin tests had a summary sensitivity of 30.7% (95% CI, 18.9%-45.9%) and a specificity of 96.8% (95% CI, 94.2%-98.3%), with a partial area under the summary receiver-operating characteristic curve of 0.686 (I² = 38.2%). Similar results were observed for subanalyses restricted to patients reporting nonimmediate maculopapular exanthema or urticaria/angioedema. Specific IgE had a summary sensitivity of 19.3% (95% CI, 12.0%-29.4%) and a specificity of 97.4% (95% CI, 95.2%-98.6%), with a partial area under the summary receiver-operating characteristic curve of 0.420 (I² = 8.5%). Projected predictive values mainly reflect the low frequency of true penicillin allergy.

CONCLUSIONS

Skin tests and specific IgE quantification appear to have low sensitivity and high specificity. Because current evidence is insufficient for assessing the role of these tests in stratifying patients for delabeling, we identified key requirements needed for future studies.

Self-reported beta-lactam intolerance: not a class effect, dangerous to patients, and rarely allergy

Introduction: About 8% of the United States population carries an unconfirmed penicillin 'allergy' in their medical record. Many physicians needlessly avoid other beta-lactam use in individuals with unconfirmed penicillin allergies. There is a significantly increased risk of developing serious antibiotic-resistant infections, and increased morbidity and mortality in those who report penicillin allergy. Areas covered: Within this study, we reviewed the relevant literature on self-reported beta-lactam allergy. We discuss how the myth of serious allergy to penicillin developed and then discuss and in detail clinically significant immunologically mediated hypersensitivity reactions. Following this discussion, we delineate the risks of not using a beta-lactam when it is the drug of choice and then discuss the epidemiology of beta-lactam-associated anaphylaxis, serious cutaneous adverse reactions, and serious systemic immunologically mediated reactions. Following these topics, we further discuss the consensus current best practices to de-label patients with reported penicillin allergy. Expert opinion: An unconfirmed allergy to penicillin offers considerable harm to patients. Many patients have low-risk allergy symptoms to penicillin who could likely tolerate the medication without having an allergic reaction. The current best practices to de-label reported penicillin allergy is the utilization of a single dose oral challenge, with 1 h of observation, in low-risk patients.

Skin microdialysis: methods, applications and future opportunities-an EAACI position paper

Skin microdialysis (SMD) is a versatile sampling technique that can be used to recover soluble endogenous and exogenous molecules from the extracellular compartment of human skin. Due to its minimally invasive character, SMD can be applied in both clinical and preclinical settings. Despite being available since the 1990s, the technique has still not reached its full potential use as a tool to explore pathophysiological mechanisms of allergic and inflammatory reactions in the skin. Therefore, an EAACI Task Force on SMD was formed to disseminate knowledge about the technique and its many applications. This position paper from the task force provides an overview of the current use of SMD in the investigation of the pathogenesis of chronic inflammatory skin diseases, such as atopic dermatitis, chronic urticaria, psoriasis, and in studies of cutaneous events during type 1 hypersensitivity reactions. Furthermore, this paper covers drug hypersensitivity, UVB-induced- and neurogenic inflammation, and drug penetration investigated by SMD. The aim of this paper is to encourage the use of SMD and to make the technique easily accessible by providing an overview of methodology and applications, supported by standardized operating procedures for SMD in vivo and ex vivo.

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.

Highlights and recent developments in food and drug allergy, and anaphylaxis in EAACI Journals (2017)

This review highlights research advances and important achievements in food allergy, anaphylaxis, and drug allergy that were published in the Journals of the European Academy of Allergy and Clinical Immunology (EAACI) in 2017. Food allergy and anaphylaxis research have continued to rapidly accelerate, with increasing numbers of outstanding developments in 2017. We saw new studies on the mechanisms, diagnosis, prevention of food allergy, and novel food allergens. Drug hypersensitivity, as well as hereditary angioedema, has been highlighted in the present review as the focus of recent developments. The EAACI owns three journals: Allergy, Pediatric Allergy and Immunology (PAI), and Clinical and Translational Allergy (CTA). One of the major goals of the EAACI is to support health promotion in which prevention of allergy and asthma plays a critical role and to disseminate the knowledge of allergy to all stakeholders including the EAACI junior members. This paper summarizes the achievements of 2017 in anaphylaxis, and food and drug allergy.