• not organic in cause

• does not involve defects in the structure of the blood vessels

• causes short-term effects

For example: Raynaud's disease or phenomenon, a condition in which the smallest arteries that bring blood to the fingers or toes constrict (go into spasm) when exposed to cold or as the result of emotional upset. This disease happens most commonly in women between the ages of 18 and 30.

• caused by structural changes, such inflammation and tissue damage, in the blood vessels

For example: Buerger's disease (thromboangiitis obliterans), a chronic inflammatory disease found chiefly in the peripheral arteries and veins of the extremities. This disease most commonly happens to men between the ages of 20 and 40 who smoke cigarettes. Symptoms include pain in the legs or feet, clammy and cold skin, and a diminished sense of heat and cold.