What are Leg Ulcers?
Ulcers are crater-like open sores that are a result of erosion of tissue. On the leg, these ulcers are visible on the skin and extend deep into the underlying tissue. Ulceration may occur for a number of reasons and with proper treatment and care, it can heal fairly quickly (acute).
However, in most cases it does not heal easily and persists for prolonged periods of time (chronic). Most leg ulcers are chronic in nature and due to underlying vascular disorders, where the blood circulation to the leg is impaired. This disrupts the normal healing mechanisms and a simple cut can progress into a deep ulcer.
What are the causes of leg ulcers?
Acute ulcers tend to occur after serious injury (trauma) or surgery and will heal with proper treatment in less than 4 weeks. It can occur even in the case of a small wound if the area becomes infected. In a healthy person, where the blood circulation is not compromised and there are no other underlying conditions, the ulcer will heal completely with proper treatment although there may be some degree of scarring of the skin.
Chronic ulcers are recurrent or persistent ulceration often related to impaired blood circulation (artery or vein) and further complicated by other conditions like diabetes. These ulcers take longer than 4 weeks to heal and tend to recur, or may not heal completely at all (non-healing/persistent).
Skin diseases, different types of skin cancer and vasculitis are other causes of both acute and chronic ulcers. A bacterial infection of even a small cut on the limb can also result in an ulcer and this is often seen in impetigo, ecythema and cellulitis. Rheumatoid arthritis and sickle cell disease are some of the uncommon causes of leg ulcers.
Ulceration due to non-infectious causes always runs the risk of an infection, which can lead to serious complications or progress to the point where amputation of the limb may have to be considered if it does not respond to other forms of therapy. Chronic leg ulcers are of a greater concern as the persistent or recurrent nature of the ulceration is at a higher risk of infection.
Chronic Ulcers of the Legs
Most chronic leg ulcers are due to vascular disturbances.
Types of Vascular Leg Ulcers
There are broadly two types of vascular leg ulcers :
- Venous ulcers (stasis) due to chronic venous insufficiency – impaired drainage of blood from the leg.
- Arterial ulcers (ischemic) due to chronic arterial insufficiency – impaired blood supply to the leg.
Venous ulcers account for the majority of chronic leg ulcers with arterial ulcers being the second most common. In all types of chronic leg ulcers, circulation in the lower limb is affected. The blood pressure within the vessels (artery, vein, capillaries) increases significantly and forces fibrinogen out of the capillary wall. It is then activated and the fibrin then forms a cuff around the capillary (pericapillary cuff), which prevents growth and repair factors in the blood from reaching the damaged area. This hampers the healing process and the ulceration progresses further. Oxygen deprivation further accelerates the growth of the ulcer.
Venous ulcers are also known as statis ulcers. This is because the underlying cause of the impaired blood circulation is a result of blood pooling in the leg due to disrupted venous drainage. It is often as a result of conditions like deep venous thrombosis (DVT) and other causes of venous obstruction (like pelvic tumors), incompetent veins/valves (varicose veins), surgery or an infection.
Some of the common clinical features include :
- Irregular shaped ulcer
- Fairly painless unless infected
- Typically affects the gaiter area of the leg (between knee and ankle)
- Swelling of the limb usually present
- Limb is warm
- Pulses on the leg may be diminished but are present
Arterial ulcers are also known as ischemic ulcers. This is because the supply of oxygenated blood to the area is impaired due to a narrowing artery. It is often a result of conditions like a blood clot (thrombus or embolus), atherosclerotic plaques (atherosclerosis) or compression of the artery (like in a pelvic tumor). Refer to blood clot in leg for more information.
Some of the common clinical features include :
- Regular shaped ulcer with ‘punched out’ appearance
- Usually painful
- Typically affects the pressure areas like the foot
- Swelling of the limb not always present
- Limb is cold
- Pulses on the leg are usually absent
These arterial ulcers tend to occur on the weight bearing areas of the foot. In diabetic neuropathy, the diminished sensation in the lower limb often results in injuries which may go by unnoticed especially if it occurs in less obvious parts of the limb, like at the bottom of the foot. Peripheral arterial disease is also present in most of these cases and hamper repair of the area for the same reasons mentioned above.
- Leg Ulcers. DermNet