Leg ulcers: Clinical practice

An ulcer is an unhealed sore or open wound that may appear on the skin or mucosal surfaces due to destruction of the epidermis that extends into the dermis and may reach subcutaneous fat or deeper tissues.

Skin ulcers may take a very long time to heal. For optimal wound healing, the wound bed needs to be well vascularized, free of devitalized tissue, clear of infection, and moist.

The general approach to treating any ulcer starts from wound debridement to remove the accumulation of devitalized tissue, as well as decreasing the bacterial load to prevent infections.

This is usually done through irrigation, typically warm isotonic saline solution; while surgical debridement with a scalpel or other sharp instruments is done for removing large areas of necrotic tissue, for chronic non healing ulcers, or when there are signs of infection.

In addition, individuals with infected ulcers should have wound cultures sent and should get started on antibiotic therapy.

Then, a dressing is applied to the ulcer to help the wound heal more quickly by providing a sterile, breathable and moist environment, as well as reducing the risk of infection. Dressings are typically changed daily or every other day.

Nonhealing ulcers may progress to gangrene, which is a hard, dry texture, usually in the distal toes and fingers, often with a clear demarcation between viable and black, necrotic tissue.

When gangrene has set in, aggressive debridement or amputation of the affected area may be required.

Skin ulcers most often appear on the legs, and can result from multiple causes.

Biopsies are not usually necessary for most ulcers, but can be helpful when the diagnosis is uncertain.

The most common causes are venous insufficiency, arterial insufficiency, and neuropathy. So they’re often classified as venous, arterial, or neuropathic.

Venous ulcers are associated with venous insufficiency due to valve dysfunction, which causes stasis of blood in the legs, and that leads to an increase in venous pressure. This in turn allows blood proteins and fluid to leak into the interstitial space.

Over time this increases the pressure in the tissues and can cause tiny capillaries to get pinched shut, ultimately leading to tissue ischemia and subsequent breakdown of the tissues - including the skin.

Some risk factors are being older, female, obese, pregnant, and standing for a prolonged period of time.

Venous ulcers are usually shallow with irregular borders and overlying yellow, fibrinous exudate.

They’re usually on the lower leg, on the "gaiter" area of the leg, which extends from the mid-calf to ankle, on the medial side of the leg, around the medial malleolus. And they can cause mild to moderate pain.

There may be associated signs like edema, varicose veins, and brown discoloration of the lower legs and feet due to hemosiderin deposition.

There may also be stasis dermatitis or lipodermatosclerosis, which is erythematous induration and fibrosis of the lower medial leg, which can also be painful.

If the diagnosis is unclear or if surgical intervention is being considered, then noninvasive venous imaging with duplex ultrasonography can be done to assess reflux and obstruction in the superficial, deep, and perforating veins.

Treatment options involve manual compression to help increase blood flow, as well as compressive bandages and stockings, and frequent periods of elevating the legs above the heart.

Surgical treatments are used in severe disease, and they include vein transplant, vein repair, or vein removal.

Arterial ulcers, also known as ischemic ulcers, are typically associated with peripheral artery disease, in which the ischemia is due to occlusion of an artery leading to reduced blood flow to the tissue, leading to tissue necrosis and ulceration.

Risk factors include diabetes, smoking, hypertension, and hyperlipidemia - all things that damage the arteries in general.

Arterial ulcers often begin as minor wounds that fail to heal because the blood supply doesn’t meet the increased demands of the healing tissue. The lesions are often dry and painful, but with little bleeding.

Arterial ulcers tend to occur on the tips of the toes, or between toes, lateral side of the leg and over bony prominences, such as on 1st or 5th metatarsal head, or pressure areas like the heel, malleoli, and shin.

Often there’s a shiny appearance to the skin, local hair loss, diminished pulses, brittle or ridged nails, and the ulcers sometimes get infected.

Nonhealing ulcers may progress to dry gangrene.

Peripheral arterial disease can be diagnosed with ankle-brachial index or ABI testing, which measures the ratio of systolic blood pressure in the ankle to the systolic blood pressure in the upper arm.

ABI range of 1 to 1.40 is what’s considered healthy or normal; values of 0.91 to 0.99 are borderline; and values lower than 0.90 are considered to be due to peripheral vascular disease.

For treatment, arterial blood flow must be reestablished with revascularization; options include percutaneous intervention, surgical bypass, or a combination of these, followed by closure of the ulcer by primary healing or secondary reconstructive surgery.

Neuropathic ulcers occur when individuals have damage to peripheral nerves involved in sensation, causing a peripheral sensory neuropathy.

There’s often reduced sensitivity to touch, temperature, and pain, and it most often involves the longest nerves, which are in the lower legs and feet.

Feet often get damaged by thermal or mechanical trauma, and the tissue breaks down and can get infected.

Neuropathic ulcers have a punched-out appearance usually occurring over pressure points on the foot or heel, but unlike arterial ulcers, they are painless with decreased sensation in the area.

The most common cause of neuropathic ulcers is diabetes mellitus, which also impairs the wound healing process.

Steps to prevent diabetic foot ulcers include tight glycemic control, good foot hygiene, diabetic socks and shoes, as well as daily foot inspections.

Other causes of peripheral neuropathy include spinal cord disorders like injury or spina bifida, alcohol abuse, nutritional deficiencies, and autoimmune diseases.

Neuropathic ulcers often go unnoticed until they’re pretty advanced, so they often need debridement of nonviable and infected tissue, revisional surgery on the bony architecture, vascular reconstruction, and graft options for soft tissue coverage. Often, amputation of the limb is required.

Now, in addition to venous, arterial, and neuropathic ulcers there are also some less common causes of leg ulcers, such as pressure, infections, pyoderma gangrenosum, skin cancer, and certain medications.

Pressure ulcers, also known as bedsores or decubitus, and they usually occur over a bony prominence on the lower extremity, often at the heel, as a result of pressure applied to soft tissue which causes either a complete or partial obstruction to blood flow.