A leg ulcer is a break in the skin that typically occurs between the ankle and the knee and fails to heal readily, usually persisting for more than two weeks despite care. These open sores are not merely surface cuts; they can extend deep into the dermal layers, signaling a serious underlying medical issue that requires professional evaluation. Leg ulcers are common, particularly in older adults, and their appearance provides important clues about their cause. Understanding the visual characteristics of these wounds is the first step toward seeking appropriate medical attention.
General Characteristics of Leg Ulcers
Most leg ulcers share several visual traits regardless of their specific origin, often presenting as a crater-like wound. The base, or wound bed, can vary in color, frequently appearing red, yellow, or a mix of colors, reflecting the condition of the tissue underneath. A red base indicates healthy, granulating tissue, while a yellow or gray color suggests the presence of dead tissue or a sticky, fibrous coating called slough.
Leg ulcers often produce an exudate, which is drainage that can range from clear and watery to thicker and purulent. The edges of the wound may be either well-defined and sharp or irregular and sloping, which is a key differentiator when determining the type of ulcer. Because these wounds involve full-thickness skin loss, they expose underlying tissues and are susceptible to infection, which can dramatically change their appearance.
Distinguishing the Major Types by Appearance
The three most common types of leg ulcers—venous, arterial, and neuropathic—each have distinct visual signatures that relate directly to their cause. Venous ulcers, which account for the majority of cases, typically form in the “gaiter area,” located on the inner side of the leg just above the ankle. These wounds are generally shallow and broad with irregular, ill-defined borders that may appear sloping.
The skin surrounding a venous ulcer often exhibits signs of long-standing pressure, including brownish discoloration (hyperpigmentation) and hardened, thickened skin. These ulcers are characteristically wet, producing a moderate to heavy amount of watery discharge due to fluid accumulation in the leg. While the ulcer itself may be painful, the discomfort is often described as a dull, aching sensation that is relieved when the leg is elevated.
Arterial ulcers tend to appear on the toes, heels, or the outer ankle, often at pressure points or sites of minor trauma. They have a distinct “punched-out” look: deep, round, and symmetrical with sharply defined edges. The wound base is frequently pale, yellow, or black due to tissue death from lack of blood flow. They produce minimal to no exudate, making them appear dry.
The skin around an arterial ulcer is often thin, shiny, and hairless, and the area may feel cool to the touch, reflecting poor circulation. These ulcers cause severe pain, which often worsens at night or when the leg is elevated, restricting the limited blood supply. The pain is temporarily relieved by hanging the leg down, which uses gravity to encourage blood flow.
Neuropathic ulcers, commonly associated with diabetes, usually develop on the soles of the feet, especially under the balls of the feet or the heels—areas subjected to high pressure during walking. These ulcers can be surprisingly deep but often appear shallow because they are surrounded by a thick, hardened ring of skin called a callus. Due to nerve damage, the patient may not experience significant pain, allowing the ulcer to become large before it is noticed.
Underlying Causes and Risk Factors
The distinct appearance of each ulcer type results directly from the underlying condition that impedes the body’s natural healing process. Venous ulcers, characterized by their irregular, shallow shape, are caused by chronic venous insufficiency. Faulty valves in the leg veins fail to efficiently return blood to the heart, causing blood to pool. This increases pressure inside the veins, forcing fluid and blood components to leak into the surrounding tissue.
Arterial ulcers, with their sharply defined, deep features, are a consequence of peripheral artery disease (PAD). PAD involves the narrowing or blockage of arteries due to the buildup of fatty deposits (atherosclerosis). This blockage starves the lower leg tissues of oxygen and nutrients, leading to tissue death, which is why the wound bed often appears pale or necrotic. Risk factors include smoking, high cholesterol, and high blood pressure.
Neuropathic ulcers, often found on the foot’s pressure points, arise from diabetic neuropathy, a form of nerve damage common in individuals with long-term diabetes. The loss of protective sensation means minor cuts, blisters, or repeated pressure go unnoticed, leading to progressive tissue breakdown. While neuropathy is the main cause, a lack of blood flow can also contribute to the severity and delayed healing of these wounds.
When to Seek Medical Attention
Any open sore on the leg that has not begun to heal within two weeks warrants a visit to a healthcare provider, as leg ulcers rarely resolve without specialized medical intervention. It is important to seek urgent care if you observe specific signs of a developing infection. These signs include a sudden increase in pain, spreading redness or warmth around the wound, or the presence of a foul odor or thick, discolored pus.
Individuals with underlying conditions like diabetes must be vigilant, as nerve damage can mask the pain associated with infection, allowing it to progress rapidly. A healthcare professional, such as a primary care physician, vascular specialist, or wound care clinic, can accurately diagnose the type of ulcer and address the root cause to facilitate proper healing and prevent severe complications.