Persistent solar urticaria. A case report.

Solar urticaria is an uncommon dermatological disease characterized by wheals developing within a few minutes after sun exposure and lasting a few hours. We describe a man in whom wheals developed on his trunk and arms more than 30 min after sun exposure and lasted more than 24 h. High doses of UVA reproduced lesions with histological features typical of urticaria. After 7 years, urticaria began to develop even in winter and without sun exposure. Our patient is unusual in that his wheals were delayed in onset and longlasting. The later association of idiopathic urticaria is an additional unusual feature.