Raynaud's phenomenon. The French tricolor.

Recent epidemiologic surveys indicate that episodic vasospasm of arterioles (Raynaud's phenomenon) is a common finding in the general population. In a small minority of these individuals, an underlying, often reversible cause or systemic disease associated with vasospasm can be identified. The range of these so-called secondary forms of vasospasm is broad and includes systemic rheumatic syndromes, vibration-induced vascular injury, drug-induced vasospasm, and infectious disorders. Several different physiologic mechanisms may be responsible for vasospasm; hyperactivity of the sympathetic nervous system and abnormal adrenergic receptor function appear to be most important.