capillaroscopy

Capillaroscopy is a non-invasive imaging technique used to visualize the microcirculation by examining capillaries, most commonly in the nailfold. It provides information on capillary density, architecture, and flow, helping to detect microvascular abnormalities in systemic diseases and in Raynaud phenomenon.

The most widely used form is in vivo nailfold capillaroscopy (NVC), performed with a stereomicroscope or a videocapillaroscope. Modern systems often use digital imaging with magnification ranging from roughly 20x to 200x and may employ immersion oil or optical methods to enhance visualization of capillary loops.

Examination procedure involves acclimatization of the patient to room temperature, warming of the hands, and cleaning of the nailfolds. A small amount of immersion oil or gel is placed on the nailfold, and images are obtained from multiple digits on both hands. Capillary loops are evaluated for density, loop morphology, diameter, presence of microhemorrhages, and areas where capillaries are absent.

Clinical use includes evaluation of Raynaud phenomenon to distinguish primary from secondary forms and assessment of microvascular involvement in connective tissue diseases such as systemic sclerosis, dermatomyositis, and lupus. Normal capillaroscopy shows evenly spaced, uniform, hairpin-shaped capillaries. Abnormal findings may include dilated and tortuous loops, microhemorrhages, architectural disorganization, and avascular areas. A characteristic scleroderma pattern may be observed, with enlarged capillaries, hemorrhages, capillary loss, and disorganization; early, active, and late variants describe progressive changes.

Limitations and interpretation: capillaroscopy is operator-dependent and relies on standardized protocols and normative references that vary by age, sex, and technique. It should be interpreted alongside clinical data and laboratory findings, as it is not a standalone diagnostic test. The procedure is generally safe with minimal risk.