August 2026 – Question of the Month
A 9-year-old boy is seen for evaluation of a reported amoxicillin allergy. Three years ago, he developed a maculopapular rash several days after starting amoxicillin for acute otitis media. He had no urticaria, angioedema, respiratory symptoms, mucosal involvement, or hypotension. The rash resolved after the medication was discontinued. His parents have avoided all penicillin antibiotics since that time.
Which of the following is the most appropriate approach to determine whether this child has a true drug hypersensitivity?
EXPLANATION
Drug allergy labels in children frequently do not represent confirmed drug hypersensitivity. A detailed history—including the medication involved, timing of symptoms, characteristics and severity of the reaction, treatment required, and subsequent exposure—is an essential first step in evaluating a suspected drug reaction.
In this patient, the delayed, uncomplicated maculopapular eruption without systemic or mucosal involvement is consistent with a nonimmediate reaction rather than a severe immediate IgE-mediated reaction. The lecture notes that although skin testing can be useful, a negative skin test does not exclude drug hypersensitivity, and drug provocation testing (DPT) remains the gold standard for diagnosis in children. Because intradermal testing can be painful and difficult in children, experts increasingly favor DPT before intradermal testing, particularly for nonimmediate reactions.
A maculopapular eruption does not by itself establish persistent penicillin allergy. In-vitro testing is available for only a limited number of drugs and has limitations in sensitivity. Intradermal testing is not the diagnostic gold standard, and blanket avoidance of beta-lactams is unnecessary; beta-lactam cross-reactivity is influenced importantly by similarities in drug side chains.