[Capillaroscopy and rheumatic diseases: state of the art].
ABSTRACT Nailfold capillaroscopy (NVC) represents the best method for analyzing microvascular abnormalities in rheumatic diseases. Raynaud's phenomenon (RP) represents the most frequent clinical aspect of microvascular involvement and is a key feature of several such diseases. Under normal conditions or in primary RP (exclusion by the cold-exposure test), the normal nailfold capillaroscopic pattern shows a regular disposition of the capillary loops within the nail bed. However, in subjects suffering from secondary RP, one or more alterations in the capillaroscopic findings should alert the physician to search for an underlying connective tissue disease. Architectural disorganization, giant capillaries, hemorrhages, loss of capillaries and avascular areas characterize more than 95% of patients with overt systemic sclerosis (scleroderma, SSc). Therefore, the term "scleroderma pattern", includes all capillaroscopic changes typical of the microvascular involvement in SSc. The capillaroscopic aspects observed in dermatomyositis and in undifferentiated connective tissue disease are generally reported as "scleroderma-like patterns". This peripheral microangiopathy can be effectively detected early in the course of the disease and studied in detail by nailfold capillaroscopy or, better, with NVC. In addition, early differential diagnosis between primary and secondary RP is the greatest advantage NVC has to offer. In addition, interesting capillaroscopic changes have been observed in systemic lupus erythematosus, antiphospholipid syndrome and Sjögren's syndrome. However, further epidemiological and clinical studies are needed to better standardize NVC patterns.