Immediate sunburn-like reaction in a patient with formaldehyde photosensitivity.

A 78-year-old man experienced pruritus, burning, and redness within minutes of exposure to sunlight. The immediacy as well as the temporary nature of the response was similar to that seen in solar urticaria, but in sharp contrast to the delayed reactions associated with sunburn and photocontact dermatitis. Photo-patch tests revealed a specific photosensitivity to formaldehyde. Despite its ubiquitous presence and its capacity to produce allergic contact dermatitis, formaldehyde, to my knowledge, has not been previously found to be a photosensitizer.