Introduction

In 1862 Maurice Raynaud described an episodic digital ischaemia due to vasospasm of the small arteries and arterioles of the extremities, precipitated by cold or emotion. It consists of intense pallor (vasoconstriction), cyanosis (spasm relaxation with a trickle of blood flow causing rapid desaturation) and rubor (increased blood flow into dilated capillaries), with full recovery in 15–45 minutes. The fingers remain normal in between the episodes.

The term ‘Raynaud's phenomenon’ is used when the cause is unknown, and if underlying cause is identifiable, it is known as Raynaud's disease. However, the syndrome is better classified into spastic and obstructive type depending on the causative factor.

Incidence

The prevalence varies with climate and probably ethnic origin. In cooler countries (UK, Scandinavian) the prevalence varies from 20 to 25%. It affects all age groups but mainly young women. Around 40–80% of Raynaud's patients have associated disease, scleroderma being the most common.

Pathogenesis

Two types: obstructive and spastic.

Obstructive arterial disease causes a decrease in resting digital arterial pressure and, in these patients, even normal vasoconstrictive response to cold or emotion is sufficient to cause symptoms. Spastic type has normal resting digital pressure and symptoms are caused due to an increased intensity of cold-induced arterial spasm. Both α2 adrenoceptors and presynaptic βreceptors are implicated in its causation.

Raynaud's disease can be associated with autoimmune diseases (SLE, RA, Sjögren's syndrome, mixed connective-tissue disorders, scleroderma), haematological diseases (mixed cryoglobulinaemia, monoclonal gammopathies, leukaemia, cold agglutinins, thrombocytosis), trauma, vibrating tools, arteriosclerosis, frostbite, Buerger's disease, hypothyroidism, thoracic outlet obstruction, and drugs.