Solar urticaria: a report on 57 cases.

BACKGROUND

Solar urticaria (SU) represents an uncommon skin disorder, characterized by pruritic erythema and wheals after sun exposure, that sometimes restricts normal daily life.

OBJECTIVE

To evaluate data concerning sex, age, natural history, associated diseases, and eliciting wavebands of 57 SU cases.

METHODS

Questionnaire for anamnestic data, laboratory examinations, phototesting.

RESULTS

Sex: 25 (44%) males, 32 (56%) females. Age: The peak age was between 20 and 30 years. Skin type (ST): 12 (21%) ST II, 39 (68%) ST III, and 6 (11%) ST IV. Time between onset and complete disappearance of SU was from 2 to more than 6 years; the main peak (37 patients) between 4 and 6 years. There were histories of atopic dermatitis 12 (21%) and asthma or rhinitis 15 (26%). Association with other urticarias (U): 13 (21%) dermographic U, 2 food U, 3 heat U. Increased immunoglobin E (IgE): 19 (33%). Eliciting wavebands: 38 (67%) visible light (VIS), 16 (28%) long ultraviolet (UVA), 3 natural sunlight. Minimal urticarial dose (MUD): 20-37.5 J/cm2 for VIS-sensitive patients, 5-10 J/cm2 for UVA.

CONCLUSIONS

In our series: 1. SU affects both sexes usually when they are under 30 years of age; 2. nearly half the patients are free of disease within 5 years; 3. in about one fourth of cases SU is associated with dermographic urticaria or displays a history of atopic dermatitis; 4. the wheals are elicited mainly by VIS or UVA; 5. SU can be prevented, at least in part, by antihistamines or by PUVA therapy.