Photosensitive lichenoid reaction to torsemide--a loop diuretic

Torsemide, a potent loop diuretic of the sulfonylurea class, has been available for clinical use in the United States since 1993. Adverse generalized and cutaneous reactions to this medication are uncommon and are usually mild and transient. In this article, we describe an 82-year-old man who had a photosensitive lichenoid reaction due to torsemide therapy, a previously undescribed phenomenon. The overwhelming presence of T lymphocytes within the lesional skin biopsy specimen and the photodistributed nature of the eruption supported a localized photoallergic cell-mediated hypersensitivity reaction to torsemide. The presumed epitope targeted in this reaction is unclear. Because of the potential risk for cross-reactivity of torsemide with the sulfonamide group of medications, torsemide should be used cautiously in sulfonamide-hypersensitive patients.