Peripheral arterial disease is an inadequate flow of the blood through arteries. The arteries are the channels leading blood to organs and muscles. If the arteries narrow or become blocked because of disease, they will not provide enough blood to muscles and organs to enable a smooth function.

Peripheral artery disease is also known as peripheral vascular disease. This topic focuses on peripheral arterial disease of the legs, which are the most commonly affected, as well as peripheral artery disease symptoms.

The most common cause of peripheral arterial disease is the appearance of a plaque inside the blood vessel. This plaque is made up of excess cholesterol, calcium and other substances in the stream of blood, which, in time, is deposited along the interior walls of all arteries, including those that supply the legs. Increased deposits of plaque results in narrowing the space through which oxygen and nutrients pass from the blood. Thus, there is an unsatisfactory blood flow to muscles and other tissues of the lower body.

This process of plaque formation - called atherosclerosis or arterial calcification - occurs usually in the body including the arteries of the legs, coronary arteries (coronary atherosclerosis) and carotid arteries. Atherosclerosis develops gradually throughout life. Cholesterol level, blood pressure and smoking contributed to increased atherosclerosis and peripheral arterial disease.

Very rarely, peripheral arterial disease can occur without contact with atherosclerosis, is caused by inflammation of blood vessels (vasculitis) and old injuries that have damaged blood vessels. The most common peripheral artery disease symptoms include intermittent claudication, an overwhelming feeling of tension or pain in the calf, thigh or lower buttock during an activity, like walking. Pain is usually triggered at the same level of effort and goes away when the effort ceases.

However, there are asymptomatic individuals. Recent research indicates that only one in three people with peripheral arterial disease present intermittent claudication. Some patients have pain in the lower limbs but not going far enough to trigger claudication. Other studies indicate that women with peripheral arterial disease are less likely to develop intermittent claudication than men.

Other symptoms of peripheral arterial disease with localization in the legs can be:
- Reduced muscle force, functionality and balance
- Sensation of coldness and numbness (paresthesia) in the foot and fingers
- Lesions (wounds) difficult to treat
- Limb pain while resting, indicating that the peripheral arterial disease gets worse
- Erectile dysfunction

Physical signs of advanced peripheral arterial disease can take the following forms:
- Fingers and feet become pale during activities or when they are raised
- Loss of hair on the legs and toes
- A red coloring in the legs when they are hanging
- Blue or red spots on legs, feet or fingers caused by reduced blood flow to tissues
- Ulcers in the foot or fingers
- Infected gangrene (dead tissue), the appearance of black skin on the limbs and feet.

The severity of peripheral arterial disease may be indicated by the appearance of more severe symptoms. However, symptoms may be influenced or confused with other illnesses that the patient might have, such as arthritis. Peripheral arterial disease may also be confused with other diseases that have similar symptoms. Claims of painful lower limbs caused by peripheral arterial disease are rarely mentioned by some patients who have higher tolerance to pain.