[Collagen diseases and microcirculation].

The microcirculation (terminal vessels with a calibre of less than 30 mu) was examined by means of capillaroscopy which was correlated with histological studies. According to the classification of vasculitis, microvasculitis is a pathological process involved in a number of collagen diseases. The study of the cutaneous lesions of leukocytoclastic angiitis is one of the best method for approaching the study of these microangiopathies, especially in the context of hypersensitivity vasculitis. The study of the microcirculation may also be valuable in other connective tissue diseases (various forms of necrotic vasculitis, lupus, scleroderma, polydermatomyositis) and in Behçet's disease. However, this study is only in its preliminary stages and the data of capillaroscopy need to be interpreted critically.