The prevalence of acute cutaneous drug reactions in a Scandinavian university hospital

To investigate the epidemiology of acute cutaneous adverse drug reactions, a cross-sectional study was designed with four visits, equally distributed over one year, to all clinical departments of a large university hospital in order to find patients with possible drug-induced exanthema of less than 2 weeks' duration. Patients were examined clinically and offered investigation for possible drug allergy, including blood tests, and skin tests when appropriate. Subsequent drug challenge tests were performed in selected cases. Finally, the history and test results were evaluated to determine the imputability of each drug as the possible culprit. In a cohort of 11,371 in- and outpatients, 131 were referred for evaluation. Twenty-nine cases of acute cutaneous drug reactions were identified, giving a prevalence of 0.33% in in-patients, 0.14% in out-patients, and 0.25% overall. Twenty-five percent of the case patients died within 6 months after the study period. The most common type of skin reactions were symmetrically distributed maculo-papular exanthema and eczematous eruptions. Several more rare types of skin reactions were each represented by a single case. beta-lactam antibiotics and chemotherapeutics were the most common eliciting drugs. The prevalence was lower than reported previously, but similar to a recent study. However, prospective studies are few and rarely performed in large hospital settings. Furthermore, variations in the pharmacotherapeutic traditions between countries may affect the outcome of such studies.