Management of drug allergy

Adverse drug reactions incorporate all unintended consequences of drug administration, whether side effects or allergies. Drug allergy is an immune mediated hypersensitivity reaction and accounts for about 10% of all adverse drug reactions. An allergic response should be suspected when: the symptoms fit a recognized pattern of allergic disease, there is a temporal relationship with drug ingestion and the class of drug is recognized as causing immune mediated reactions. The diagnosis of drug allergy has significant impact on future therapeutic strategies and therefore care should be taken that this diagnosis is made carefully through an appropriate history, examination and investigation. Complications due to overdiagnosis lead to inappropriate restriction of drug choice whilst under recognition will allow further unwanted iatrogenic adverse events. There are multiple potential differential diagnoses of drug allergy (Figure 1.)