Pathogenesis and treatment of Raynaud's phenomenon.

The pathogenetic theories and treatment of Raynaud's phenomenon are reviewed. In primary Raynaud's disease, most evidence supports a local defect at the digital artery level, with vasoconstriction or vasospasm of the digital arteries inducing the color changes. Normal sympathetic activity, low transmural arterial distending forces, and serotonin may be associated factors in the production of vasospastic attacks. In Raynaud's phenomenon, persistent vasoconstriction, thickened vessel walls, increased blood viscosity, and low digital artery blood pressure distal to obstructions may lead to vasospastic attacks with normal sympathetic nerve stimuli. Since the underlying cause of primary Raynaud's disease is unknown, treatment involves the use of agents to reduce sympathetic nerve activity or to prevent vascular smooth muscle contraction. Most patients will respond to conservative measures, but if they fail nifedipine is the drug of choice and alleviates the syndrome in about two thirds of patients. Reserpine and guanethidine may be as effective, but well-controlled studies have not been performed. The beneficial response to prazosin is moderate and dissipates with time. Side effects with these drugs prevent their use in many patients. Diltiazem and nitroglycerin ointments are of questionable value. Ketanserin, a serotonergic S2-receptor antagonist, which has been shown to decrease the frequency of vasospastic attacks, and parenteral prostacyclin are among the new promising therapies.