CHILDHOOD ACTINIC PRURIGO - 3 CASES IN A FAMILY WITH SUBTYPE HLA-DR-0407

Background. Actinic prurigo, as idiopathic skin reaction involving lig ht-exposed areas, was first described in American Indiens. Actinic pru rigo was early considered to be a particular form at polymorphous phot otoxicity, but can be identified as a specific entily on the bases of clinical features and epidemioiogical characteristics. Case reports. T hree children in the same family developed photosensitive reactions ea rly in childhood with characteristic polymorphous and persistent eczem a-like or papulo-nodular pruriginous lesions which predominated in lig ht-exposed areas and appeared several hours after exposure to sun. The lesions persisted during the winter season. The lesions followed a ch ronic course but tended to improve at puberty. Rootline laboratory tes ts, serum and urine porphyrin levels and antinuclear factors were norm al. Histology and photobiology explorations gave non-specific results. Discussion. These observations have three points in common with actin ic prurigo observed in American Indians. HLA typing showed that our th ree patients, as in white patients in Great Britain, had a significant association with a specific HLA DR1 subtype: DRB10407. This DRB1*040 7 allels could play a role in initiating the immune response to a ligh t-induced peptide antigen. This particular genetic predisposition, if confirmed in other studies, would be an additional argument for distin guishing actinic prurigo as a specific polymorphous phototoxicity enti ry.