Avascular areas on nailfold capillary microscopy of patients with Wegener's granulomatosis

Over the past 25 years, nailfold capillary microscopy (NCM) has gained diagnostic value in the field of rheumatology based on descriptive data from patients with distinct connective tissue diseases (CTD). We prospectively analysed NCM findings from 116 patients selected for NCM by one of the following indications: (1) suspected diffuse or limited scleroderma or dermatomyositis, (2) evaluation of Raynaud's phenomenon (RP) or (3) suspected small-vessel vasculitis. Nailfold haemorrhages, and enlarged and tortuous nailfold capillaries ('lupus pattern') were found to comparable degrees in patients with CTD and primary RP. Only giant loops, bushy capillaries and avascular areas indicated CTD; 92% of patients with Wegener's granulomatosis (WG) had avascular areas. From all nailfold capillary abnormalities, only bushy capillaries, giant loops and avascular areas support a suspected CTD. A lupus-like pattern is not diagnostic. Avascular areas are a typical abnormality in patients with WG, for which NCM findings have not been described previously.