[Solar urticaria. Case report and literature review]

Solar urticaria is a rare type of inducible urticaria characterized by wheal and erythema formation shortly after exposure to sunlight or to an artificial light source; its pathophysiology is not yet entirely understood. The treatment of choice, in addition to exposure avoidance, consists in antihistamine administration.

This is the case of a 27-year-old woman with no personal history of allergic diseases and with a 2-year history of erythema and wheals in photo-exposed areas associated with sunlight exposure for periods longer than 10 minutes. A provocation test was carried out; she was started on fexofenadine at 4-fold the standard dose (720 mg/day). Six weeks later, a new challenge was carried out without the antihistamine being discontinued; the reaction was less severe, but she continued with erythema for the first 60 minutes post-exposure. After 3 months on high-dose antihistamines, she referred marked improvement in her quality of life and tolerance to brief sunlight exposure (for less than 15 minutes).

Solar urticaria is a rare process but with a high impact on the patient. The use of antihistamines partially relieves symptoms and allows better tolerance to lighting expositions.