Hydroa vacciniforme and solar urticaria.

Hydroa vacciniforme (HV) and solar urticaria (SU) are uncommon immunologically mediated photodermatoses. HV occurs almost exclusively in children, usually beginning in childhood and remitting spontaneously by adolescence. Association with chronic Epstein-Barr virus infection has been reported in HV, which raises the possibility of lymphoproliferative disorders in these patients. SU is characterized by skin erythema, swelling, and whealing immediately after sun exposure. Although several treatment options are available, the management of both conditions remains a challenge.