A comparative study of toxic erythema of pregnancy and herpes gestationis.

We compared the clinical features, histopathology, immunopathology and immunogenetics of 30 patients with toxic erythema of pregnancy and 24 patients with herpes gestationis. Although we found some clinical and histopathological overlap we highlighted several important differences. In toxic erythema of pregnancy prominent striae were frequently present. Herpes gestationis was suggested by the occurrence of periumbilical lesions, acute exacerbations immediately after delivery, and persistence of the eruption for more than 3 weeks post-partum. In herpes gestationis, immunofluorescence studies were consistently positive, there was a high frequency of HLA-B8 and an association with autoimmune thyrotoxicosis. Toxic erythema of pregnancy did not share these immunological features. Therefore we feel that toxic erythema of pregnancy and herpes gestationis should continue to be classified as separate disorders.