Raynaud's phenomenon (RP) is an exaggeration of the normal physiological response to cold. Typically the fingers turn white (ischaemia), then blue (deoxygenation) and then red (reperfusion). The toes (and nose and ears) may also be affected.

RP can present at any age. Primary (idiopathic) RP typically presents in the teens or twenties. However, children also may present with RP and in 12 to 15 year olds the prevalence of RP has been estimated to be 15%. When RP presents in older age groups, it is especially important to look for an underlying cause. Secondary causes of RP include not only connective tissue diseases but also hand-arm-vibration syndrome, atherosclerotic disease, haematological disorders, and certain drugs and chemicals. The pathogenesis of RP is complex and includes abnormalities of the vasculature, of neural control elements, and intravascular factors.

It is important to separate primary from secondary RP. In patients with primary RP, abnormalities in the digital vasculature are thought to be purely functional: structural vascular disease (as seen in systemic sclerosis) does not occur. As a result, patients with primary RP do not progress to irreversible tissue injury, whereas patients with secondary RP, for example systemic sclerosis-related RP, may develop digital ulcers, pitting scars, or gangrene. Early recognition of systemic sclerosis is possible through careful and early evaluation of the patient presenting with RP: this evaluation includes checking for antinuclear antibody (and if there is concern also for systemic sclerosis-specific autoantibodies) and examining the nailfold capillaries by capillaroscopy. For this reason, RP is the main clinical indication for nailfold capillaroscopy. In primary (idiopathic) RP the nailfold capillaries should be normal whereas abnormal capillaroscopy raises suspicion of an underlying systemic sclerosis-spectrum disorder. Raynaud's phenomenon and abnormal nailfold capillaries are two of the criteria in the American College of Rheumatology/European League Against Rheumatism 2013 classification criteria for SSc.

Treatment of RP depends on its severity and on whether or not there is an underlying cause which may be amenable to intervention. Treatment options include general measures, drug treatment and (in patients who have progressed to ulceration or gangene) surgery.

Disclosure of Interest None declared

DOI 10.1136/annrheumdis-2014-eular.6338