A Rapid Drug-Induced Granulomatous Dermatitis to Amlodipine.

A 65-year-old man with a history of coronary artery disease, myocardial infarction, hypertension, hypereosinophilic syndrome, and chronic hepatitis B presented with a pruritic, generalized rash 3 weeks after initiating amlodipine for refractory hypertension. Physical examination demonstrated widespread indurated pink-red papules coalescing into plaques over the trunk, extremities, face, and scalp. Laboratory evaluation, including complete blood count, metabolic panel, and peripheral flow cytometry, was unremarkable. A skin biopsy revealed vacuolar interface change with a perivascular lymphocytic and granulomatous infiltrate containing eosinophils, consistent with an interstitial granulomatous drug reaction (IGDR). Amlodipine was discontinued and he was initiated on high-dose systemic and high-potency topical corticosteroids. Within 1 week, he experienced significant improvement in pruritus and had not developed any new lesions. Prednisone was successfully tapered without recrudescence of his rash. IGDR is an uncommon hypersensitivity reaction that is most associated with broadly prescribed cardiovascular medications such as calcium channel blockers (CCB) and statins. IGDR rests along a spectrum of reactive granulomatous dermatitides that are triggered by medications, autoimmune diseases, malignancies, or other underlying conditions. Recognition of IGDR by history, exam, and pathology is important for cardiologists and other prescribing clinicians, as its clinical presentation differs from more common drug exanthems as it can develop weeks to months after starting a CCB and can persist long after it is withdrawn. This case underscores the importance of maintaining vigilance for drug eruptions in patients presenting with new rashes while on antihypertensive therapy.