Cross‐reactivity in beta‐lactams after a non‐immediate cutaneous adverse reaction: experience of a reference center for toxic bullous diseases and severe cutaneous adverse reactions

Cross‐reactivity in beta‐lactams after a non‐immediate cutaneous adverse reaction: experience of a reference center for toxic bullous diseases and severe cutaneous adverse reactions:

Abstract

Background

Cross‐reactivity among beta‐lactam antibiotics (BL) is essentially reported in immediate hypersensitivity.

Objectives

To evaluate cross‐reactivity beyond BLs in patients with non‐immediate cutaneous adverse drug reaction (non‐immediate CADR) managed in a dermatology reference center of toxic bullous and severe CADRs.

Patients/Materials/Methods

We conducted a retrospective single center study in consecutive patients consulting between 2010 and 2018 with an active BL‐suspected non‐immediate CADR and explored by cutaneous tests [patch tests (PT) and intradermic tests (P‐IDR)] for at least three penicillin’s subclasses and amino‐ and nonamino‐cephalosporins (at least one aminocephalosporin). Cross‐reactivity among subclasses was investigated for patients with positive tests.

Results

We included 56 patients, among whom 46 amoxicillin‐suspected were and 7 cephalosporin‐suspected. Twenty‐nine had severe CADR and 27 had non‐immediate maculo‐papular exanthema (MPE). Twenty‐two had positive tests (18 for AS and 4 for CS). Among the 18 positive amoxicillin‐suspected, 10 (55.6%) showed cross‐reactivity with one or more other BL: 9 (50%) with another penicillin and 3 (16.5%) with a non‐aminocephalosporin. No amoxicillin‐ or cephalosporin‐suspected patient showed cross‐reactivity with aztreonam or carbapenems. P‐IDR showed cross‐reactivity only once.

Conclusion

After a suspected BL‐induced non‐immediate CADR, a large allergologic exploration is needed to confirm the diagnosis and evaluate cross‐reactivity. In our population including cases of severe CADRs and MPE with late delay of onset, cross reactivity was frequent and PT were sufficient to this purpose. The frequent cross‐reactivity among penicillins encourages stopping this whole family and to test cephalosporins, aztreonam and carbapenems for which cross‐allergies are rarer.