Raynaud's phenomenon-an update on diagnosis, classification and management.

Raynaud's phenomenon (RP) is used to describe a symptom complex caused by digital vascular compromise. RP is a clinical diagnosis. The typically episodic nature of RP has resulted in a reliance upon patient self-report for diagnosis. The term 'primary RP' is generally applied when no underlying pathology can be demonstrated. Whilst 'primary RP' is currently considered a distinct disorder, there is evidence that the term may comprise several entities that include a functional vasospastic disorder, a physiologically appropriate thermoregulatory response, subclinical atherosclerosis and 'cold intolerance'. Optimal management may differ depending on cause. The term 'secondary RP' encompasses a broad range of rheumatological, haematological, endocrinological and vascular pathology. RP can range from relatively benign but intrusive vasospasm, to the progressive obliterative microangiopathy of systemic sclerosis (SSc), in which severe digital ischaemia can threaten tissue viability. SSc has formed the focus of much of the research into RP but, consistent with most medical symptom complexes, the aetiopathogenesis of RP varies greatly dependent on cause. Vasospasm within the digital macro- and microvasculature occurs in SSc, but digital ischaemia is further compounded by a progressive obliterative microangiopathy. Recent work exploring the patient experience of SSc-RP is challenging the 'episodic' paradigm of 'Raynaud's', with important implications for clinical trials utilising diary-based patient-reported outcome instruments for assessing Raynaud's symptoms. This review shall examine the causes, pathogenesis, clinical features, classification and management of RP. A practical approach to the evaluation and management of RP is outlined, highlighting important knowledge gaps and unmet research needs where applicable. Key Points • Raynaud's phenomenon is a symptom complex related to digital vascular compromise secondary to broad-ranging pathology. • Raynaud's phenomenon, as currently classified, likely encompasses a number of aetiopathogenic processes. • Raynaud's phenomenon causes significant disease-related morbidity in autoimmune rheumatic diseases such as systemic sclerosis.