The clinical and photobiological characteristics of solar urticaria in 40 patients

Forty patients with solar urticaria, 16 male and 24 female, were examined p ersonally during the past 25 years. The median age at onset of symptoms was 32 years, ranging from 13 to 76 years. Most commonly (45%) solar urticaria first appeared during the third decade, The mean duration of the disease w as 3.6 years at presentation, The action spectrum was found in the visible light range in 24 patients (60%), in the ultraviolet (UV) A range in four, in the UVB in four, from the UVA to UVB in three, from the UVA to visible l ight in one and in a broad range from WE to visible light in four patients. An inhibition spectrum was detected in 13 of 19 patients (68%), occurring at longer wavelengths than the action spectrum in 12 of these cases. The au gmentation spectrum was found in only four of 14 patients (29%) examined, T wenty-four of 31 patients (77%) developed an urticarial reaction to autolog ous serum, which had been previously irradiated iii vitro at the action spe ctrum for that patient. In a single patient, solar urticaria was caused by a drug, namely chlorpromazine. In two patients, polymorphic light eruption occurred in association with solar urticaria. No single modality of treatme nt was satisfactory, but combined use of antihistamines, sunbathing, psoral en WA photochemotherapy and/or sunscreening agents partially suppressed the symptoms.