Raynaud's phenomenon: a review.

Raynaud's phenomenon is a final result of many disease processes and is rarely a primary dysfunction and more an autoimmune phenomenon. It seems to be the result of a failure of vasodilatation than a sympathetic overactivity. Digital arteries are affected in only 40%, more often the fault is at the arteriolar and capillary level. The controlling mechanism of small vessels seems intact but the role of central versus peripheral factors is unresolved. The method of thermal entrainment has shown the action of sex hormones on vascular control especially at the time of ovulation. Heredity is a major factor in aetiology, myxoedema is common (16%). The role of prostaglandin metabolism is not clear. Platelets are hyperactive, blood viscosity is raised and red cells more rigid than normal. Sympathectomy fails in 81% of cases.