Clinical relevance of combining Thermography with Nailfold Capillaroscopy to improve differentiation between primary and secondary Raynaud’s Phenomenon

Objectives: Early microvascular damage and dysfunction are clinically mirrored in Raynaud’s phenomenon (RP). Currently, nailfold capillaroscopy (NC) is applied to differentiate between primary RP (PRP) and secondary RP (PRP), associated with connective tissue disease. However, abnormal morphology can also be caused due to age-related changes and cardiovascular disease. Thermography (TG) is a non-invasive technique which enables quantification of cutaneous vascular function. An approach using both NC and TG could improve the differentiation between PRP and SRP. Methods: Thirty RP patients (PRP, n = 21; SRP, n = 9) underwent nailfold capillaroscopy and thermography. Morphologic features were scored and patients were categorized according to the guidelines of EULAR Study group on Microcirculation in Rheumatic Diseases. TG of the hand was performed before, directly and ten minutes after a cold challenge test. Baseline images and rewarming curves were analyzed. Results: Capillary abnormalities with NC were found in all SRP patients (9/9) and in 48% (10/21) of PRP patients. Out of 10 PRP patients with altered capillary morphology, 9 (90%) had a cardiovascular disease. For all patients mean temperature was significantly higher 10 minutes after cold induction than before (p < 0,01). The gradient of the rewarming curve was significantly lower in patients with SRP compared to PRP patients (p = 0.015). Conclusions: Nailfold capillaroscopy and thermography can reliably be used to measure microvascular damage and dysfunction. Additional thermography can assist in differentiating between PRP and SRP, especially in elderly patients or in presence of a cardiovascular disease. Keywords: Raynaud’s phenomenon; Nailfold capillaroscopy; Thermography