Solar urticaria treated with intravenous immunoglobulins

Background Solar urticaria (SU) is a rare idiopathic photodermatosis induced immediately after sun exposure. This disorder may considerably restrict normal daily life and management is extremely difficult when treatment with oral H1 antihistamines and sun avoidance are ineffective. Objective We sought to report the effectiveness of intravenous immunoglobulins (IVIG) in severe SU. Methods We performed a retrospective multicentric study via the mailing of a questionnaire to the French photodermatology units to analyze all cases of patients with SU who were treated with IVIG. Results Seven patients (5 women) with a mean age of 40 years (range 32-55 years) and a mean disease duration of 5 years (range 2-10 years) received IVIG. The administration schedule differed from one patient to another: 1.4 to 2.5 g/kg were infused over 2 to 5 days. Five of 7 patients obtained a complete remission. The number of courses necessary to obtain clinical remission varied from 1 to 3 courses. Complete remission was maintained during 4 to more than 12 months but antihistamines were still required. In one case, psoralen plus ultraviolet A photochemotherapy was administered. Limitations Retrospective study design, limited number of patients, and variations in the IVIG administration schedule could limit the interpretation of the results. Conclusion Our case series suggests a beneficial effect of IVIG in severe SU but additional prospective trials including a larger number of patients are needed to demonstrate the effectiveness of IVIG and to specify the optimal modalities of their administration in this disease.