Sores vary widely in appearance depending on their cause, but most share a few common features: broken or damaged skin, a change in color from the surrounding area, and some combination of redness, swelling, or fluid. The specific shape, color, and texture of a sore can tell you a lot about what’s causing it and whether it needs attention. Here’s what different types of sores actually look like.
Canker Sores
Canker sores are the most common type of mouth sore. They’re round or oval with a white or yellow center surrounded by a red border. Minor canker sores are small, usually under a centimeter, and heal on their own within a week or two. Major canker sores are larger and deeper, with defined round borders that can become irregular as the sore grows. They appear on the inside of the lips, cheeks, tongue, or soft palate, never on the outer skin of the face.
Cold Sores
Cold sores caused by herpes simplex virus go through a distinct visual progression. They almost always appear on or around the lips rather than inside the mouth.
The first sign isn’t visible at all. You’ll feel tingling, burning, or itching in one spot. Within a day or two, one or more small blisters filled with clear fluid appear on a base of red skin. After a few days, those blisters break open into shallow, red, weeping sores. As they dry, a yellow or brown crust forms over them. The crust eventually flakes away over the course of a week or so, leaving healed skin underneath.
Syphilis Chancres vs. Herpes Lesions
Two sexually transmitted infections cause sores that look quite different from each other. A primary syphilis chancre is typically a single, firm, painless sore. It has clean, raised edges and appears at the site of infection, often on the genitals, anus, or mouth. Because it doesn’t hurt, people sometimes miss it entirely.
Genital herpes looks different: multiple small, painful blisters clustered together on red, inflamed skin. They break open into shallow ulcers, weep, and then crust over, similar to cold sores. The pain is a key distinguishing feature. A single painless sore points toward syphilis; a painful cluster points toward herpes.
Shingles Rash
Shingles produces one of the most visually distinctive sore patterns. The rash appears as clusters of small, fluid-filled blisters that follow a band-like path along one side of the body, typically wrapping around the torso or appearing on one side of the face. It almost never crosses the body’s midline, so it stops roughly at the center of the chest or back. New blisters continue forming over three to five days before the rash progressively dries and scabs over. The band-like, one-sided pattern is the hallmark that separates shingles from other blistering conditions.
Sores That Won’t Heal on the Skin
A sore that doesn’t heal within a few weeks deserves closer attention. Basal cell carcinoma, the most common form of skin cancer, often starts as a shiny, translucent bump with a pearly or pinkish appearance on lighter skin. Tiny blood vessels may be visible on or near the surface. On darker skin tones, it can appear as a brown, black, or blue lesion with dark spots and a slightly raised, translucent border. These sores may bleed, scab over, and then reopen repeatedly without ever fully healing.
Leg and Foot Ulcers
Sores on the lower legs and feet often relate to circulation problems or diabetes, and their appearance varies by cause.
Venous ulcers develop near the ankle, usually on the inner side. They have irregular but well-defined borders and a moist, reddish wound bed. The surrounding skin is often discolored, swollen, or thickened from long-standing fluid buildup.
Arterial ulcers look different. They tend to appear on the toes, forefoot, or heel. The wound bed is often pale yellow with dead tissue and no healthy pink tissue visible underneath. The surrounding skin may look thin, shiny, and cool to the touch because of reduced blood flow.
Diabetic foot ulcers can begin subtly. Early warning signs include a change in skin color or temperature on the foot, callus buildup in one area, or a small blister or irritated spot that isn’t healing. Because diabetes can reduce sensation in the feet, these sores sometimes go unnoticed until they’ve grown significantly.
Signs a Sore Is Infected
Any sore can become infected, and the visual clues are fairly consistent regardless of the original cause. Infection typically brings increased redness spreading outward from the sore’s edges, swelling, warmth, and drainage that changes color. Pus from an infected wound can be white, yellow, green, pink, or brown, and it usually has a noticeable foul smell. Red streaks extending away from the sore along the skin suggest the infection is spreading and needs prompt attention.
What Healing Looks Like
Knowing what a healthy healing sore looks like is just as useful as recognizing a problem. A sore that’s healing well develops granulation tissue: moist, bumpy, shiny red or pink tissue that fills in the wound from the bottom up. This is a good sign. It means blood flow is adequate and the body is rebuilding.
Unhealthy signs in a healing wound include slough, a stringy or filmy layer that ranges from white to yellow to green depending on bacterial activity. It may stick firmly to the wound bed or sit loosely on the surface. Eschar is another warning sign: dry, leathery, dark brown or black tissue that forms a hard covering over the wound. Stable eschar is firm and dry with no drainage or surrounding redness. Unstable eschar feels spongy or boggy, may produce drainage, and suggests dead tissue that’s trapping problems underneath.
Dark, dusky-colored granulation tissue that looks pale or grayish rather than bright pink or red can indicate poor blood flow or early infection, even if the sore isn’t obviously worsening yet.