Thiazide-induced photosensitivity: a study of 33 subjects.

The clinical features, action spectrum and subsequent course, are described in 33 subjects with thiazide-induced photosensitivity. The reaction appeared to be phototoxic in nature. The wavelengths involved were those of the longer UVA and, not infrequently, also the shorter UVB waveband. In most instances withdrawal of the drug resulted in clearance of the clinical reaction and a return of the action spectrum to normal. In the few subjects in whom the photosensitivity persisted, either in the form of the clinical reaction or an abnormal action spectrum, or both, either a specific photodermatosis was present or another potentially photoactive drug was being taken. In no instance, was there evidence of the induction of long-term chronic photosensitivity (persistent light reaction) following the withdrawal of the thiazide drug.