Uro-dermatological problems of a construction worker: paraaminobenzoic acid as a systemic photosensitizer.

A 51-year-old man suffered from an acute eczematous rash confined to the air- and light-exposed areas of the skin. As a construction worker he was exposed to common occupational allergens such as epoxy resins, but there was also remarkable holiday-associated sun exposure. He did not use any sunscreen agents. Several weeks before the onset of skin eruptions, conservative treatment of Peyronie's disease with oral PotabaTM (potassium paraaminobenzoate) had been started. Airborne contact dermatitis to volatile allergens was ruled out, while photopatchtesting revealed photoallergy to paraaminobenzoic acid (PABA). In sunscreens, PABA has mostly been abandoned due to its known topical photosensitization properties, but it has not yet been recognized as a systemic photosensitizer.