The study objectives were twofold: 1. To develop a method of direct nailfold capillaroscopy (NFC) applicable to a wide range of paediatric patients. 2. To analyze capillaroscopy images in a representative group of healthy children and rheumatology patients using this method. We examined 157 healthy children aged 7 months to 17 years and 46 children with various diseases: juvenile idiopathic arthritis (JIA: 18), diffuse connective tissue diseases (CTD: 10), systemic lupus erythematosus (SLE: 5), primary vasculitis (Henoch-Schönlein purpura, HSP: 9, other types of vasculitis, VAS: 6) and Raynaud’s disease (RS: 3). A stereomicroscope with fibreoptic illumination was used. The following parameters were analysed in the end capillary row: linear density, tortuosity, abnormal loops, avascularity and disarrangement. The mean linear density in healthy children ranged from 7.3 – 8.7 cap/mm, the tortuosity was 20 – 60 % (grade 0.8 – 1.4). In healthy children abnormal capillaries as well as avascularity were present extremely rarely, the degree of disarrangement was also low ranging from 0.7 – 1.4 in a 4-point scale. Children under 4 years of age had lower capillary counts and a higher tortuosity as well as disarrangement degree (p < 0.01). In the whole group tortuosity decreased significantly with age (p < 0.01). Patients with CTD had lower linear density (6.0 cap/mm), higher number of abnormal loops, higher avascularity as well as degree of disarrangement while children in JIA, HSP, VAS and RS groups had normal capillaroscopic findings. The NFC method presented is technically feasible in children of the widest age range. Despite a relatively high interindividual variability of capillaroscopic parameters our NFC modification provides valuable information on the presence and degree of microangiopathy, characteristic for certain rheumatic diseases in childhood. NFC should be performed routinely when diffuse connective tissue disease is suspected even in the presence of isolated Raynaud’s phenomenon.

        Key words: nailfold capillaroscopy, children, microangiopathy