La capillaroscopies is an examination that consists of examining under a microscope the small blood vessels (capillaries) at the level of cuticles, around the fingernails. The goal is to assess the quality of the microcirculation, that is to say of the blood circulation at the level of the smallest vessels.

We speak more precisely of “periungual” capillaroscopy, which means “around the nail”. It is an old and simple technique, first described in 1912.

Used initially in dermatology to assess the skin microcirculation, capillaroscopy is mainly used today in people with Raynaud’s phenomenon, a blood circulation disorder that manifests itself by the constriction of the small vessels at the extremities, especially in case of cold or stress (the fingers become white or blue).

Capillaroscopy is also useful in the diagnosis of certain systemic diseases (connectivitis and vasculitis), including systemic sclerosis, systemic lupus erythematosus, dermatomyositis and mixed connectivitis (Sharp’s syndrome).

Capillaroscopy is a quick and painless examination.

The principle is simple: the patient places his hands under the lamp of a microscope (capillaroscope) which allows a magnification ranging from 20 to 200 times.

This allows the doctor to visualize the capillaries by transparency at the level of the nail cuticle where the skin is thin, after the simple application of a drop of microscope oil. A camera or camera can take pictures. In general, one examines 8 fingers (not the thumbs because they are less easy to handle).

A healthy capillary looks like a red curl in the shape of a hairpin, regular and unbroken. Several abnormalities can be seen by the doctor, including widening or narrowing of capillaries, irregularities, groups of fused capillaries, microhemorrhages, etc.

In case of Raynaud’s syndrome, periungual capillaroscopy is most often normal. However, there is a so-called “secondary” form, which is more serious, in which abnormalities such as dilation of capillaries, microhemorrhages or areas devoid of capillaries (called desert areas) are found.