Skin ulcers are open sores or lesions that develop on the skin when tissue breaks down, exposing underlying layers. These wounds often result from factors like poor blood circulation, prolonged pressure, or underlying medical conditions. Unlike minor cuts or scrapes, skin ulcers often do not heal easily and can become chronic.
Basic Visual Characteristics
A skin ulcer presents as an open lesion, with its appearance varying by severity and cause. The wound bed, the deepest part of the ulcer, can display a range of colors. A red or pink wound bed indicates healthy, new tissue. Yellow tissue, known as slough, suggests dead or dying cells. Black tissue, called eschar, signifies necrotic tissue.
The edges of a skin ulcer can provide clues about its nature. Some ulcers have irregular borders, while others may be well-defined or have a “punched-out” appearance. The depth of an ulcer can vary from shallow, affecting only superficial skin layers, to deep, potentially exposing muscle, tendon, or bone. Drainage, or exudate, from the ulcer can range from clear fluid to cloudy, yellow, or green pus, which often signals an infection.
How Different Ulcers Appear
Different types of skin ulcers exhibit distinct visual features, often linked to their underlying causes and common locations. Understanding these differences can help recognize the specific type of ulcer.
Pressure ulcers, also known as bedsores, form over bony prominences where sustained pressure reduces blood flow. Common sites include:
The sacrum
Heels
Hips
Elbows
Shoulders
In their earliest stage (Stage 1), they appear as intact skin with non-blanchable redness. As they progress (Stage 2), a shallow open wound or blister may form. More advanced stages (Stage 3 and 4) involve full-thickness tissue loss, extending into fat, muscle, or even bone, and may show slough or eschar.
Venous ulcers frequently occur on the lower legs, especially above the ankle, and are caused by poor blood circulation in the leg veins. These ulcers often have an irregular shape and are typically shallow. The surrounding skin may appear discolored, often brown or reddish-brown, due to blood pooling, and can be swollen, shiny, or scaly. Venous ulcers commonly produce moderate to heavy drainage, giving them a “wet” appearance.
Arterial ulcers, which result from inadequate blood flow due to narrowed or blocked arteries, are most often found on the feet, toes, heels, or outer ankle. They are characterized by a “punched-out” or round shape with well-defined borders. These ulcers are often deep, with a pale, yellow, brown, or black wound bed, and typically have minimal drainage. The skin around an arterial ulcer may be cool to the touch, thin, shiny, dry, and may show hair loss.
Diabetic ulcers commonly develop on the feet, particularly on pressure points like the sole, ball of the foot, or tips of the toes. These ulcers often arise from nerve damage (neuropathy), which can reduce sensation. They can vary in appearance but frequently have an irregular shape and may be surrounded by a thick callus. The wound bed can be pale, granular, or covered with yellow slough or black tissue, and some may show signs of inflammation or drainage.
Visual Indicators of Worsening
Changes in the visual characteristics of a skin ulcer can indicate worsening, such as infection or further tissue damage. One common sign is increased redness or warmth extending beyond the ulcer’s edge, suggesting spreading inflammation or infection. Swelling around the wound is another indicator that the ulcer may be deteriorating or infected.
The presence of pus, particularly if it is yellow, green, or has a foul odor, suggests a bacterial infection. An increase in the amount of drainage, or a change in its consistency, can also be a warning sign. If the ulcer appears to be growing larger or becoming deeper, it signals that the tissue breakdown is progressing. The development of new black or dark tissue within or around the wound bed indicates tissue death. Additionally, any noticeable changes in the color of the surrounding skin, such as purple or dark red discoloration, can point to deep tissue injury or compromised blood flow.