Lichenoid Eruption and Alopecia Associated with Captopril Treatment

A 72-year-old man experienced a lichenoid eruption and alopecia linked to captopril treatment. The skin lesions appeared psoriasiform but histologically matched a lichenoid eruption, with features like hyperkeratosis and a dense infiltrate in the dermis. The eruption persisted despite potent steroid ointments but cleared after stopping captopril, suggesting a causal link supported by a positive mast cell degranulation test, indicating an immunological mechanism. While alopecia in drug reactions can result from follicle-destroying inflammation, the specific cause of hair loss in this patient was unclear, and it was not related to zinc deficiency or loss of taste, which are known side effects of captopril.