Functional peripheral arterial disease is much less common than occlusive peripheral arterial disease Occlusive Peripheral Arterial Disease Occlusive peripheral arterial disease is blockage or narrowing of an artery in the legs (or rarely the arms), usually due to atherosclerosis and resulting in decreased blood flow. Symptoms depend... read more 
. Normally, the arteries of the arms and legs widen (dilate) and narrow (constrict) in response to changes in the environment, such as a change in temperature, changes in blood flow, or signals from the brain. Functional peripheral arterial disease usually occurs when the normal mechanisms that dilate and constrict these arteries are exaggerated. The affected arteries constrict more tightly and more often. These changes in constriction can be caused by
An inherited defect in the blood vessels
Disturbances of the nerves that control the dilation and constriction of arteries (sympathetic nervous system Autonomic nervous system The peripheral nervous system consists of more than 100 billion nerve cells (neurons) that run throughout the body like strings, making connections with the brain, other parts of the body, and... read more )
Injuries
Drugs
Functional peripheral arterial disorders include acrocyanosis Acrocyanosis Acrocyanosis, a functional peripheral arterial disease, is a persistent, painless bluish discoloration of both hands and, less commonly, of both feet, caused by spasm of the small blood vessels... read more 
, erythromelalgia Erythromelalgia Erythromelalgia is a rare syndrome in which small arteries (arterioles) of the skin dilate periodically, causing a burning pain, making the skin feel hot, and making the feet and, less often... read more , and Raynaud syndrome Raynaud Syndrome Raynaud syndrome, a functional peripheral arterial disease, is a condition in which small arteries (arterioles), usually in the fingers or toes, narrow (constrict) more tightly than normal in... read more 
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