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Microscopic examination of nailfold capillaries is accepted as an investigational tool for adults with connective tissue diseases. Abnormalities are found in more than 80% of adult patients with scleroderma or related disorders. There are fewer data about children but workers in Birmingham (
) have described their findings in healthy adults and children and in children with rheumatic diseases.
They performed nailfold capillary microscopy (nailfold capillaroscopy, NFC) using a stereomicroscope with fibre optic illumination. Images were enlarged 66 times (3 mm section of nailfold magnified to 19.8 cm on screen) and photographed using a colour digital video camera. Six parameters were assessed: capillary density, loop width, tortuosity, avascularity, disarrangement, and number of abnormal vessels. They examined 18 healthy children aged 2–18 years (mean 7 years), 20 healthy adults, 15 children with juvenile idiopathic arthritis, 18 with connective tissue diseases (juvenile dermatomyositis, systemic sclerosis, mixed connective tissue disease, or overlap syndromes), eight with systemic lupus erythematosus, nine with primary Raynaud’s syndrome, and three with vasculitis.
Healthy children had fewer and wider capillary loops than healthy adults, linear capillary density increasing gradually with age. Median capillary density was 6.7 capillaries per mm in children and 8.9 capillaries per mm in adults. Median capillary loop width was 47 μm (children) versus 41 μm (adults). Children with connective tissue diseases had fewer (4.9/mm) and broader (162 μm) capillary loops. Morphologically abnormal capillaries (at least two abnormal capillaries on at least two of eight fingers (not thumbs) examined) were found in 11 of the 18 children with connective tissues diseases but in no other children. These changes were most marked in children with dermatomyositis. Children with connective tissue diseases also had a greater degree of avascularity and general disarrangement of capillary pattern. Findings were, on the whole, normal in children with juvenile idiopathic arthritis, systemic lupus erythematosis, or Raynaud’s syndrome.
Nailfold capillary microscopy may provide useful information to aid the diagnosis of connective tissue diseases in children.