Periungual capillaroscopy is a simple noninvasive exploration contributing to the clinical examination. It is highly contributive to the etiological diagnosis of Raynaud's phenomenon and is the simplest means of detecting scleroderma early. Capillaroscopy has also largely contributed to better understanding of the pathogenesis of vascular disorders encountered in acrosyndromes. Experience has shown however that clinical indications should be more precise and results interpreted with more scientific rigor (J Mal Vasc 1999; 24: 357-362).