Positive serum specific IgE has a short half‐life in patients with penicillin allergy and reversal does not always indicate tolerance

Abstract

Specific IgE to penicillins declines over time stressing the importance of a close time relation between diagnostic work-up and clinical reaction. Reversal of previously positive s-IgE may still be associated with positive penicillin challenges and/or re-boostering of s-IgE to positivity.