Does incorporation of a cold challenge provide additional diagnostic information in thermographic assessment of Raynaud's phenomenon?

Infrared thermography (IRT) provides a safe, non-invasive, indirect measure of vascular function. In addition to its many other clinical applications, IRT has developed an important place in the assessment of patients with Raynaud's phenomenon (RP), particularly those with underlying disease such as systemic sclerosis (SSc). Several studies have attempted to establish the best thermographic parameter by which to diagnose Raynaud's phenomenon. Many of these studies have incorporated a local cold challenge to allow dynamic assessment whilst attempting to recreate the conditions of an attack of Raynaud's phenomenon "in vivo". Recent studies suggest that baseline thermographic assessment alone may be sufficient to differentiate between healthy controls, primary RP and SSc. In this paper we shall explore the various thermographic parameters devised for the assessment of RP and question the contribution of the cold challenge.