Rybojad M, Moraillon I, Manciet J R, Delanoe J, Prigent F, Bourrat E, Morel P
Service de Dermatologie, Hôpital Saint-Louis, Claude Vellefaux, Paris.
Ann Dermatol Venereol. 1998 Jan;125(1):18-20.
Actinic prurigo, as idiopathic skin reaction involving light-exposed areas, was first described in American Indians. Actinic prurigo was early considered to be a particular form at polymorphous phototoxicity, but can be identified as a specific entity on the bases of clinical features and epidemiological characteristics.
Three children in the same family developed photosensitive reactions early in childhood with characteristic polymorphous and persistent eczema-like or papulo-nodular pruriginous lesions which predominated in light-exposed areas and appeared several hours after exposure to sun. The lesions persisted during the winter season. The lesions followed a chronic course but tended to improve at puberty. Clinical laboratory tests, serum and urine porphyrin levels and antinuclear factors were normal. Histology and photobiology explorations gave non-specific results.
These observations have three points in common with actinic prurigo observed in American Indians. HLA typing showed that our three patients, as in white patients in Great Britain, had a significant association with a specific HLA DR1 subtype: DRB10407. This DRB10407 alleles could play a role in initiating the immune response to a light-induced peptide antigen. This particular genetic predisposition, if confirmed in other studies, would be an additional argument for distinguishing actinic prurigo as a specific polymorphous phototoxicity entity.
光化性痒疹是一种累及光照暴露部位的特发性皮肤反应，最初在美国印第安人中被描述。光化性痒疹早期被认为是多形性光毒性的一种特殊形式，但根据临床特征和流行病学特点可被认定为一种特定的疾病实体。
同一家庭的三名儿童在幼年时就出现了光敏反应，有特征性的多形性且持续存在的湿疹样或丘疹结节性瘙痒性皮损，主要出现在光照暴露部位，日晒数小时后出现。皮损在冬季持续存在。病程呈慢性，但在青春期有改善倾向。临床实验室检查、血清和尿卟啉水平及抗核因子均正常。组织学和光生物学检查结果无特异性。
这些观察结果与在美国印第安人中观察到的光化性痒疹有三点共同之处。HLA分型显示，我们的三名患者与英国白人患者一样，与一种特定的HLA DR1亚型：DRB10407有显著关联。这种DRB10407等位基因可能在引发对光诱导肽抗原的免疫反应中起作用。如果在其他研究中得到证实，这种特殊的遗传易感性将是将光化性痒疹作为一种特定的多形性光毒性疾病实体加以区分的又一论据。
