Photosensitivity from nalidixic acid*

Abstract

Seven patients with a bullous photodermatitis from nalidixic acid are described. Bullae develop characteristically on the dorsal aspects of the feet and on the lower legs, but also elsewhere, in patients taking the drug who are exposed to a high level of ambient sunlight. At times, the clinical picture may be confused with porphyria cutanea tarda. Abnormal reactions to sunlight may continue for several months after the acute stage, whether or not the drug is stopped, but some patients may continue to take the drug if direct sunlight on the skin is avoided. Investigations showed that long wave ultraviolet radiation appears to be responsible for the reaction and it proved possible to induce photosensitivity in three volunteers who took the drug for I week. The Honorary Editors of The Proceedings of the Royal Society of Medians kindly gave permission for details in the abridged version of this paper to be published.