Background: Adverse drug reactions pose an increasing diagnostic challenge in hospitals and in outpatient clinics. When consecutive or repeated allergic drug eruptions are suspected, patch testing is a useful diagnostic tool for determining the causative drugs.
Objectives: The aim of the study was to identify patient cases with multiple delayed-type drug sensitizations by using patch testing.
Methods: Eight hundred and eleven patients with suspected drug allergy were patch tested during a 9-year period.
Results: Multiple delayed drug sensitizations were found in 12% of those patients with positive results in drug patch testing.
Conclusions: Drug patch testing is useful in cutaneous adverse drug reactions where multiple drugs are suspected. Multiple drug sensitizations can be found in a proportion of patients who have delayed drug allergies. In addition to drug reactions with eosinophilia and systemic symptoms, these patients may have repeated exanthemas or contact dermatitis.
Keywords: adverse drug reactions; cross-reactions; multiple sensitization to systemic drugs; patch test.
© 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.