[Pigmented livedo. Histologic design and pathogenetic hypothesis].

Pigmented livedo is a frequently encountered disease. It occurs as an ochre reticular membrane which does not disappear when the limb is raised. It is characteristic in persons who already have livido reticularis and who expose themselves for several hours every day to the heat from chimneys or foot-warmers. We wanted to study the histological context of this disease in a group of female patients that we kept under observation. The data that we compiled showed that it is due to lymphocytic vasculitis accompanied by atrophy of the epidermis, hyperpigmentation of the basal keratinocytes and telangiectasia. Our pathogenetic hypothesis is that it involves vasculitis "a calore", with atrophy of the epidermis, telangiectasia and melanoid pigmentation, which is the cause of the characteristic brown pigmentation.