Approximately 10 per cent of all leg ulcers are arterial ulcers. Feet and legs often feel cold and may have a whitish or bluish, shiny appearance. Arterial leg ulcers can be painful. Pain often increases when your legs are at rest and elevated.  You can reduce pain by sitting on the edge of the bed with your feet on the floor. Gravity will then cause more blood to flow into your legs. Ulcers are breaks in the layers of the skin that fail to heal. They may be accompanied by inflammation. Sometimes they don't heal and become chronic. Chronic foot and leg ulcers mainly affect the elderly. People with diabetes are at special risk of developing foot ulcers, and foot care is an important part of diabetes management.

 
People with arterial leg ulcers often suffer from intermittent claudication. The condition causes cramp-like pains in the legs when walking.  This is because the leg muscles don't receive enough oxygenated blood to function properly. Claudication pain usually goes away if you stand still for a few minutes. Not all people with intermittent claudication have leg ulcers.
 
What causes arterial leg ulcers?
 
Arteries are the tubes that carry blood from the heart to the body's tissues. The tissues receive oxygen and nutrients from the blood. The used blood, which now contains carbon dioxide and other by-products, is carried via the veins from the tissues back to the heart. Arterial leg ulcers are caused by poor blood circulation as a result of narrowed arteries. They are also caused by damage to the small blood vessels from long-standing diabetes.

Characteristics of arterial ulcers:

• Usually found on the feet, heels or toes.

• Frequently painful, particularly at night in bed or when the legs are at rest and elevated. This pain is relieved when the legs are lowered with feet on the floor as gravity causes more blood to flow into the legs.

• The borders of the ulcer appear as though they have been ‘punched out’

• Associated with cold white or bluish, shiny feet

• There may be cramp-like pains in the legs when walking, known as intermittent claudication, as the leg muscles do not receive enough oxygenated blood to function properly. Rest will relieve this pain.

Diabetes also increases the likelihood of atherosclerosis (narrowing of the arteries). This means people with diabetes have a much increased risk of developing arterial ulcers.

The long-term effect of diabetes on the nerves increases the likelihood of trauma to the feet. It causes a lack of sensation in the feet, which makes ulcers more likely to appear.  But these ulcers are often neglected because they don't cause pain. If ulcers aren't treated, they can lead to more serious problems. Diabetic ulcers have similar characteristics to arterial ulcers but are more notably located over pressure points such as heels, tips of toes, between toes or anywhere the bones may protrude and rub against bedsheets, socks or shoes. In response to pressure, the skin increases in thickness (callus) but with a minor injury breaks down and ulcerates.  Infected ulcers characteristically have yellow surface crust or green/yellow pus and they may smell unpleasant. There may be surrounding tender redness, warmth and swelling (cellulitis).

Why are people with diabetes prone to foot ulcers? A combination of the following complications develop in some people with diabetes.

Reduced sensation of the skin on the feet

Diabetic's nerves may not work as well as normal because even a slightly high blood sugar level can, over time, damage nerves. This is a complication of diabetes called 'peripheral neuropathy of diabetes'. The nerves that take messages of sensation and pain from the feet are commonly affected. If you lose sensation in parts of your feet, you may not know if you damage your feet. For example, if you tread on something sharp, or develop a blister due to a tight shoe. Therefore, you are more prone to problems such as minor cuts, bruises, blisters. Also, if you are not sensitive to pain from the foot, you will not protect these small wounds by not walking on them. Therefore, they can quickly worsen and develop into ulcers.

Narrowing of arteries (blood vessels) going to the feet

If you have diabetes you have an increased risk of developing 'furring' of the arteries. This is caused by fatty deposits called atheroma that build up on the inside lining of arteries. This can reduce the blood flow to various parts of the body. The arteries in the legs are quite commonly affected. This can cause a reduced blood supply ('poor circulation') to the feet. Skin with a poor blood supply does not heal as well as normal and is more likely to be damaged. Therefore, if you get a minor cut or injury, it may take longer to heal and is prone to worsen and develop into an ulcer. In particular, if you also have reduced sensation and cannot feel the wound.

What increases the risk of diabetics developing foot ulcers ?

If you have reduced sensation to your feet (see above). The risk of this occurring increases:

• the longer you have diabetes, and the older you are.
• if your diabetes is poorly controlled. This is one of the reasons why one aim of treating diabetes is to keep the blood sugar level as near normal as possible.

If you have narrowed arteries (see above). The risk of this occurring increases:

• the longer you have diabetes, the older you become, and if you are male.
• if you have any other 'risk factors' for developing 'furring of the arteries'. For example, if you smoke, do little physical activity, have a high cholesterol level, high blood pressure, or you are overweight.

 If you have had a foot ulcer in the past.

 If you have other complications of diabetes such as kidney or eye problems.

 If your feet are more prone to minor cuts, grazes, corns or calluses which can occur:

• if you have foot problems such as bunions which put pressure on points on the feet.
• if your shoes do not fit properly which can put pressure on your feet.
• if you have leg problems which affect the way that you walk, or prevent you from bending to care for your feet.

Diabetic ulcer assessment

There are four severity stages of diabetic foot ulcers.   Most diabetic foot ulcers are like "icebergs." Unlike a normal wound a diabetic foot ulcer can be largely hidden. It may appear small on the surface but extend very deep, even to the bone. More often, diabetic foot ulcers begin with pressure on the bottom of the foot.