The Prevalence of Suspected and Challenge‐Verified Penicillin Allergy in a University Hospital Population

Abstract

Suspected penicillin allergy is common among hospitalised patients, but the quality of the information given by the patient is often doubtful. Alleged penicillin allergics are likely to be treated with more toxic, broad-spectered, and more expensive antibiotics, with effects on microbial resistance patterns and public economy as a consequence. We performed a cross-sectional case-control study with two visits to all clinical departments of a large university hospital in order to find in-patients with medical files labelled ''penicillin allergy'' or who reported penicillin allergy upon admission. Patient histories were obtained via a questionnaire, and they were offered investigation for penicillin allergy with specific IgE, basophil histamine release, skin prick tests, intradermal tests and drug challenge tests. Finally, the pharmaco-economical consequences of the penicillin allergy were estimated. In a cohort of 3642 patients, 96 fulfilled the inclusion criteria giving a point-prevalence of alleged penicillin allergy of 5% in a hospital in-patient population. Mean time elapsed since the alleged first reaction to penicillin was 20 years. The skin was the most frequently affected organ (82.2%), maculo-papular exanthema (35.4%) and urticaria (10.4%) being the most frequently reported reactions. 25% did not recall the time of their reaction. 82.2% did not remember the name of the penicillin they reacted to. 34.8% had been treated with penicillins after suspicion of penicillin allergy had been raised. None of these reacted to penicillins. 33.3% of the patients receiving antibiotics during their current hospitalisation were prescribed penicillins. 2% developed non-severe exanthema. The average acquisition costs for antibiotics to penicillin allergic patients were s 278, compared to s 119 had they been nonallergics. The prevalence of suspected penicillin allergy was lower than reported elsewhere. A substantial number of patients failed to recall basic information about their alleged allergy. Patients reporting penicillin allergy upon admission and labels stating penicillin allergy on medical files are ignored in almost a third of patients receiving antibiotics. The acquisition costs for antibiotics to penicillin allergic patients were higher, compared to the cost had the patients been nonallergics.

A Study of Adverse Drug Reactions in Patients Treated with Penicillins in a Rural Tertiary Care Hospital

“…[10,11] The absence of organized continuing medical education programs and problematic physician attitude are other problems that add to under reporting of the adverse drug reaction. [12] There was predominance of female sex for adverse drug reactions which was similar to a study conducted by Albin S et al 13 The mean age of patients was 38.37 years which was less as compared to another study conducted by Jakob E. Borch et al [14] Amoxicillin and clavulanic acid combination was the most common penicillin causing ADRs. But studies done by Sara et al and Trubiano et al showed amoxicillin alone as most common penicillin causing ADRs.…”

“…Most common system affected was dermatological which was in line with other studies. [13,14] This increased reporting of dermatological ADRs could be due to easy recognition of dermatological reactions than involving other organ systems. [17] Most of the reactions were of probable causality according to WHO criteria since drug rechallenge was not done in any of the cases.…”

Full-Course Drug Challenge Test in the Diagnosis of Delayed Allergic Reactions to Penicillin

“…Twenty-two consecutive patients with a self-reported history of an allergic reaction to penicillin on day 2 or later in the course of penicillin treatment referred for routine investigation of penicillin allergy and with negative specific IgE to penicillin G and V, ampicillin and amoxicillin, as well as negative SPT, IDT and DCT were included [3]. All anamnestic reactions were evaluated by the authors and preceded the investigations by more than a year.…”

“…In the remaining 64% of patients, a mean of 20 years had passed since the reaction. In these patients, reaction occurred on day 2 or later [3]. A question that needs to be answered is therefore: will more patients react during a DCT if exposed to the suspected penicillin for a longer time, thus improving sensitivity and the predictive values of the entire diagnostic work-up?…”

Improving the Effectiveness of Penicillin Allergy De-labeling

“…[1][2][3][4] Most do not have either true or persistent allergies, with >90% able to tolerate penicillin after thorough assessment. 1,3 Unnecessary avoidance of penicillin increases health care costs, due to the use of more expensive and/or less effective alternative antibiotics, and contributes to the development of antibiotic resistance. 5,6 Penicillin de-labeling strategies are an increasingly recognized as a valuable component of antibiotic stewardship programs.…”