The importance of distinguishing normal capillaroscopy findings form (pathognomonic) abnormal (pathological) findings, lies in the fact that this distinction allows the differentiation between a primary Raynaud’s phenomenon characterized by normal capillaroscopic findings from a secondary RP due to systemic sclerosis (SSc) and diseases of the scleroderma spectrum, characterized by (patognomonic) abnormal findings on capillaroscopy. Diverse terminology had been described for RP, LeRoy and Medsger proposed criteria for the strict definition of primary RP and of secondary RP due to SSc. Amongst others these criteria encompass capillaroscopy.To be able to speak of a primary RP, these criteria require a normal capillaroscopic pattern. In the normal capillary pattern capillaries of the distal row of the nailfold have an open hairpin shape, a homogenous size, are regularly arranged in a parallel fashion and their number ranges between 6 to 14 per mm with a mean of 9. The morphological pattern of nailfold capillaries is remarkably constant in normal individuals. However, across the population there exists a wide variation in the ranges of the normal morphology. Andrade et al. reported capillaroscopic findings on the largest described healthy persons study population (800 healthy persons). In this study, also morphological anomalies were seen in 34% of the whole healthy person population but few in each individual. However, certain features, such as giant capillaries or extensive avascularity seem not to be present in a normal population and should be considered as pathological. On the contrary, patients with a secondary Raynaud’s phenomenon due to SSc show pathognomonic abnormal (pathological patterns) patterns on capillaroscopy. The majority of patients with clinically recognizable SSc show, very characteristic combination of capillary abnormalities (giant capillaries, loss of capillaries in the nailfold, hemorrhages and abnormal shapes [= neoangiogenesis], such as ramifications), the “scleroderma-type” changes, which can easily be assessed through pattern recognition. Recently, Cutolo et al. qualitatively assessed the nailfolds of an SSc cohort with patients fulfilling the American College of Rheumatology (ACR) criteria for SSc with the nailfold videocapillaroscopy (NVC) technique (magnification X200). According to the relative prevalences of those abnormalities he classified the patterns found in SSc into the “early”, the “active” and the “late” pattern. Besides this, the detection of pathognomonic abnormal capillaroscopic patterns on capillaroscopy also allows us to diagnose SSc “early”, before skin involvement has occurred. In this way LeRoy and Mesdger proposed in 2001 criteria for the “early” diagnosis of SSc, with RP as single criterion. These criteria incorporate SSc-specific autoimmune antibodies and microvascular techniques, more specifically the “scleroderma-type” changes on capillaroscopy. These criteria have been recently validated in a large prospective study. Of note, also in more recently proposed criteria for very early diagnosis of SSc (VEDOSS) these pathological patterns on capillaroscopy play an important role.
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Disclosure of Interest None Declared