Drug Allergy Mimics

When approaching a case of apparent drug allergy, the consulting clinician should consider a broad differential diagnosis. This article presents a series of cases that could be commonly referred to an allergist for assessment as "drug allergy," however, a real diagnosis exists that mandates a different diagnostic and treatment strategy, including a case of inducible laryngeal obstruction, multiple drug intolerance syndrome, viral rash, seizure due to metastatic malignancy, and hemophagocytic lymphohistiocytosis initially diagnosed as drug reaction and eosinophilia with systemic symptoms. The initial misdiagnoses of these patients delayed or interfered with their medical care, emphasizing the importance of accurate diagnoses for the benefit of our patients.