Occupational photoallergic contact dermatitis to thiourea in a firefighter.

Thioureas are a relatively uncommon cause of allergic contact dermatitis and a rare cause of photoallergic contact dermatitis. They are primarily used as vulcanization accelerators in the production of neoprene, and common sources of exposure include gloves, shoe insoles, wet suits, and orthopedic braces. We report a multifactorial case of severe episodic photoallergic contact dermatitis to thiourea in a 29-year-old firefighter. Multiple sources of neoprene exposure were identified, including a firefighting mask, continuous positive airway pressure strap, and hockey helmet.