Drug allergy: fact or fiction?

From our clinical practice, it was apparent that patients often reported drug allergies without a substantiating history. A prospective study over six months was undertaken to examine the reporting of drug allergies by hospital patients. Based on the history, allergic reactions were triaged into one of three categories: high probability of an allergic reaction, low probability of an allergic reaction, and uncertain, where the history was incomplete or unclear. Of 1519 patients interviewed, 133 (9%) reported prior drug allergies. The most commonly implicated agents were penicillin (74%), septrin (6%), aspirin (6%), cefuroxime (2%) and trimethoprim (2%); 61% of reactions were deemed to be high probability, with the remainder either low (29%) or uncertain (10%) probability. It was apparent that patients often considered drug allergy to be synonymous with adverse reaction. Preventing patients from being labelled as drug allergic, thus being denied therapy with first-line agents, requires patient education and vigilance by doctors in their history-taking.