Diagnostic tests in patients with Raynaud phenomenon

Margaret J. Larché, MD, is a professor of medicine in the Division of Rheumatology at McMaster University and director of the Canadian Scleroderma Research Group (CSRG).

What to pay attention to in patients with Raynaud phenomenon? Which diagnostic tests should be routinely performed?

In terms of what to look out for, we call them red flags and that makes us concerned when you take a history. So, things like Raynaud that is very severe, Raynaud that can affect the thumb is most often caused by secondary rather than primary Raynaud. And other features such as ulcers on the fingertips or something we call dilated nailfold capillaries—and those are little swelling of the vessels at the fingertip, at the cuticle, where the skin joins the nail. And we look out for that using a magnifying glass. We can do that simply using something like an otoscope or ophthalmoscope, or you can do it with another form of magnification, like a DermLite [dermatoscope], or you can buy a device called a videocapillaroscope, which is much more expensive but gives much better magnification. So you can really have a good look there.

So, if you’ve got features on history and examination that might suggest an underlying secondary cause, then I would go on to do some bloodwork, and my bloodwork would be predominantly looking for a connective tissue disease or a hematological problem causing the secondary Raynaud. So, I would do an antinuclear antibody (ANA) as one of my first tests, and then moving on to other organs, such as a complete blood count, and looking at the kidneys, for example.