M Toronto Myositis Centreat St. Michael's Hospital
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Nailfold capillaroscopy.

Nailfold capillaroscopy is a painless, close-up look at the tiny blood vessels at the base of your fingernails. It helps your team spot patterns linked to dermatomyositis, overlap conditions, and Raynaud’s.

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Painless and quick, about 15 minutes.

Nothing breaks the skin, no needles are used, and you can do everything as normal afterward.

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What it is

A close look at tiny blood vessels.

Nailfold capillaroscopy uses a special magnifier or a camera-microscope to look at the small blood vessels (capillaries) at the base of your fingernails, an area called the nailfold. A drop of clear oil is placed on the skin so the vessels show up clearly. Nothing breaks the skin, and you feel nothing. In a healthy nailfold, these vessels form neat, regular loops.

What it tells us

Why the test is done.

When the capillaries are tidy and evenly spaced, that is reassuring. In dermatomyositis, antisynthetase syndrome, and overlap conditions, and in some people with Raynaud’s, they can look different: enlarged or giant loops, gaps where vessels have dropped out, tiny areas of bleeding, and a disorganised pattern. Seeing these changes helps your team support a diagnosis of dermatomyositis or a related connective-tissue disease, tell apart harmless Raynaud’s from Raynaud’s linked to an autoimmune condition, and sometimes follow how things change over time.

What to expect

During the test.

The test itself
  • You sit comfortably with your hands resting on a table.
  • A drop of oil is placed at the base of a few fingernails.
  • The clinician looks through a magnifier or a camera, and may take pictures to compare at future visits.
  • It takes about 10 to 20 minutes.
Good to know
  • Your hands need to be warm, since cold changes the vessels, so you may be asked to warm them first.
  • There are no needles and nothing to recover from.
  • You can drive and return to normal activities right away.

Is it safe?

Capillaroscopy is completely safe and painless. Nothing is injected, nothing breaks the skin, and there is no recovery time.

Getting ready

How to prepare.

Your results

The clinician notes the pattern and shares it with your Centre team, who will explain what it means alongside your other results. The test is often repeated over time to watch for any change.

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This guide is for learning, not medical advice. Your team will explain your own test, and every person’s situation is a little different. Always follow the instructions you are given.

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