The Importance of Amoxicillin and Amoxicillin-Clavulanate Determinants in the Diagnosis of Immediate Allergic Reactions to β-Lactams

Abstract

Background: Immediate allergic reactions to β-lactam antibiotics are considered to be one of the most important drug hypersensitivities. A positive skin test (ST) with a combination of major and minor penicillin determinants is usually sufficient to recommend avoidance of the culprit drug, whereas a negative ST is usually followed by an oral challenge test (OCT). Recently, concern has been raised regarding the role of amoxicillin (AMX) ST in the diagnosis of AMX allergy. Objective: The aim of this study was to examine the additive value of AMX determinants in STs of patients with immediate hypersensitivity reactions to AMX or AMX-clavulanate (AMX-C). Methods: Patients with a history of immediate AMX or AMX-C allergy underwent an ST using a combination of penicilloyl-polylysine (PPL) and minor determinants as well as AMX. An ST with AMX-C was added when appropriate. Results: Thirty-one patients were evaluated. Eight patients, all of them with a history of AMX allergy, had positive reactions only to the AMX component. Two patients with AMX-C allergy had a positive ST reaction only to the AMX-C component. Moreover, only 14 patients (13 with AMX and 1 with AMX-C allergy) had a positive reaction to PPL, whereas most patients (54.8%) had positive reactions to other determinants. One patient, who was positive for AMX, developed several urticarial lesions after the test. Conclusions: Skin testing with AMX and AMX-C is mandatory in patients with immediate allergy to these drugs. Failure to perform it may result in a false-negative ST jeopardizing these patients with anaphylactic reactions during a hazardous OCT.

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

“…Selective sensitization to aminopenicillins has been reported in up to 50% of patients in other series. 20 , 21 , 22 , 23 , 24 A study from the United Kingdom reported testing of more than 1000 patients, in whom monosensitization with amoxicillin was demonstrated in 48%, with 70% of the patients having a negative result of testing to major and minor determinants. 25 Given the rise in amoxicillin allergy, our findings suggest that a panel comprising amoxicillin and benzyl penicillin may be sufficient in at least Australian and European populations, in which amoxicillin use is predominant.…”

Recent Advances in Clinical Allergy and Immunology

“…In patients with suspected allergy to amoxicillin, skin tests for determinants of amoxicillin and amoxicillin-clavulanate, in addition to major and minor penicillin determinants, are recommended in order to avoid false negative tests, and thus to decrease the need for oral provocation tests [83]. In children with an EBV infection a skin rash developed in 18.6%, of whom 50% were treated with antibiotics.…”

Clinical history in suspected cases of immediate allergy to beta-lactam

“… 3 Although mandatory, these tests, are technically demanding, time consuming and not commonly available. 4 In cases where the clinical history is compatible with non-immediate allergy, the negative predictive value is very high and oral challenge can be performed safely with no need for ST. 5 , 6 , 7 Nevertheless, the accuracy of focused clinical history, when immediate reaction to BL is suspected, has not been evaluated previously.…”