The role of capillaroscopy and thermography in the assessment and management of Raynaud's phenomenon.

Most patients with Raynaud's phenomenon (RP) have "benign" primary RP (PRP), but a minority have an underlying cause, for example a connective tissue disease such as systemic sclerosis (SSc). Secondary RP can be associated with structural as well as functional digital vascular changes and can be very severe, potentially progressing to digital ulceration or gangrene. The first step in management is to establish why the patient has RP. This short review discusses the role of nailfold capillaroscopy and thermography in the assessment of RP. Nailfold capillaroscopy examines microvascular structure, which is normal in PRP but abnormal in most patients with SSc: the inclusion of abnormal nailfold capillaries into the 2013 classification criteria for SSc behoves clinicians diagnosing connective tissue disease to be familiar with the technique. For those without access to the gold standard of high magnification videocapillaroscopy, a low magnification dermatoscope or USB microscope can be used. Thermography measures surface temperature and is therefore an indirect measure of blood blow, assessing digital vascular function (abnormal in both PRP and SSc). Until now, the use of thermography has been mainly confined to specialist centres and used mainly in research: this may change with development of mobile phone thermography.