Patients with drug reactions -: is it worth testing?

Background: Unevaluated drug reactions that lead to the prescription of expensive alternative medication is the reason why the European Academy of Allergy and Clinical Immunology guidelines recommend verification. We evaluated whether a structured test procedure in patients with drug reactions is worth the potential risk. Methods: We retrospectively analysed the charts of a cohort of 291 (220 females/71 males) consecutive patients from January 2003 to June 2004, who presented at the department's allergy outpatient clinic with histories of drug reactions. Twenty-three patients reported more than one independent episode resulting in 325 cases. All patients underwent the following procedure: (1) detailed history; (2) skin test and/or beta-lactam-specific IgE and; (3) if inconclusive, each patient was offered provocation testing - if needed with alternative medication. Results: We evaluated reactions to 130 antibiotics, 90 to nonsteroidal anti-inflammatory drugs, 36 to local anaesthetics and 69 to other drugs. An association between drug intake and reaction was confirmed in 100 and excluded in 157 cases. Fourteen of 104 drug provocation tests (DPT), among these four reactions to placebo, yielded positive results but were managed without difficulty. In 68 cases, the procedure remained inconclusive. Additionally, we recommended 197 safe alternative regimens to 85 patients. Overall, our test procedure resulted in clear-cut recommendations to 82.1% (239/291) of the patients. Conclusions: A standardized work-up including DPTs in patients with drug reactions leads to clear-cut advice concerning future tolerability or avoidance of certain drugs including recommendations for alternative medication in the vast majority of patients at the cost of only a low risk of mild side effects.