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Naproxen-induced pseudoporphyria: appearance of new skin lesions after discontinuation of treatment.

Non-steroidal antiinflammatory drugs (NSAIDs) are routinely used in the therapy of chronic inflammatory joint diseases in childhood. Recently the NSAID naproxen was recognized to induce pseudoporphyria. This rare photodermatitis is characterized by skin fragility and vesiculation, resulting in shallow scarring. We report 4 children with juvenile rheumatoid arthritis who developed naproxen-induced pseudoporphyria. All children had received naproxen for more than 5 months when pseudoporphyria occurred. A disorder of porphyrin metabolism was excluded by analysis of the urine, serum and erythrocytes. Previous reports on naproxen-induced pseudoporphyria described a rapid disappearance of blisters after discontinuation of treatment. However, in our patients, new lesions appeared for up to 5 weeks after discontinuation of the therapy and skin fragility was apparent for up to 6 months after cessation of treatment. Since naproxen is a widely used drug in the treatment of children with juvenile rheumatoid arthritis parents of fair-skinned children should be alerted to the possibility of this rare adverse effect.