Value of capillary microscopy in the diagnosis of hereditary hemorrhagic telangiectasia.

BACKGROUND Hereditary hemorrhagic telangiectasia (HHT) is a hereditary disorder, leading to easily bleeding telangiectases on the skin and mucosal surfaces. The disease is associated with arteriovenous malformations in multiple organs. Potentially serious complications warrant an early diagnosis. Telangiectases are the hallmark of the disease, but may be difficult to distinguish. OBJECTIVES To evaluate the value of capillary microscopy in the diagnosis of HHT and to compare the capillary pattern of the fingernail folds in patients with HHT and healthy persons. SETTING Outpatient department of a general hospital. PARTICIPANTS A random sample of 54 patients with HHT and a volunteer sample of 40 healthy persons. MAIN OUTCOME MEASURE The difference in the capillary pattern between patients with HHT and healthy volunteers. RESULTS Forty-five (83%) of 54 patients with HHT had giant loops between the normal capillaries in the nail fold. Two patients had only enlargement of the draining limb of the capillary. Seven patients (13%) had no vascular abnormalities in the nail fold. Seven of 9 patients with HHT but without cutaneous telangiectases had microvascular abnormalities. None of the volunteers had vascular abnormalities. The difference between both groups was significant (chi2, P<.001). CONCLUSION Capillary microscopy can be a valuable tool in diagnosing HHT.