Drug allergy mimicking recurrent endocarditis - A cautionary tale

The identification of a drug responsible for a suspected allergic reaction still depends mainly on circumstantial evidence and is quite often a diagnosis of exclusion. One of the most important factors in the diagnosis is the awareness of the physician that an unexplained symptom or sign may be related to a drug that the patient is receiving. If the drug in question is an antibiotic that is treating the infection, the difficulty of distinguishing the clinical manifestations of an allergic reaction from those of the original condition becomes even greater.