Sores come in many forms, and their appearance depends entirely on what’s causing them. Some are small, fluid-filled blisters that crust over. Others are open wounds with distinct borders and colors. By knowing what different types of sores look like at each stage, you can get a much better sense of what you’re dealing with.
Cold Sores
Cold sores, caused by the herpes simplex virus, typically appear on or around the lips. They progress through a predictable sequence. First, you’ll feel tingling, burning, or itching in a spot before anything is visible. Within a day or two, one or more small blisters filled with clear fluid appear on the surface of the skin, with red skin surrounding and beneath them. These blisters can also show up inside the mouth or throat.
After a few days, the blisters break open into shallow, red, weeping sores. As they dry out, a yellow or brown crust forms over the top. That crust eventually becomes a scab, which flakes away as the skin heals underneath. The full cycle from tingling to healed skin usually takes 7 to 10 days.
Canker Sores
Canker sores look quite different from cold sores and are easy to distinguish once you know what to look for. They appear inside the mouth only, on the inner lips, cheeks, or tongue. A canker sore is a round, white or yellow sore surrounded by a red border. They’re typically single sores rather than clusters, and they’re not contagious. They tend to be painful, especially when eating or talking, and most heal on their own within one to two weeks.
Genital Herpes Sores
Genital herpes sores start as small, blister-like bumps that tend to appear in a cluster. You may notice itching or tingling in the area a day or two before the sores become visible. The blisters then take on an ulcer-like appearance, eventually opening and oozing before forming a scab as they heal. They can appear on the genitals, inner thighs, or buttocks. A first outbreak is usually more severe than recurrences.
Syphilis Chancres
A syphilis sore, called a chancre, looks and behaves very differently from herpes. It’s a small, firm, round sore that appears at the site of infection, often on the genitals, rectum, tongue, or lips. The key distinguishing feature is that a chancre is usually painless, which is why many people don’t notice it at all. It typically appears as a single sore rather than a cluster. Without treatment, the sore heals on its own within a few weeks, but the infection progresses silently.
Shingles Rash
Shingles produces one of the most visually distinctive rashes. It appears as a band or stripe of blisters that wraps around one side of the body, most commonly along the torso or across the face. This pattern follows the path of a single nerve. The rash almost never crosses the body’s midline, so if you see blisters on your left side only, that’s a strong visual clue. The blisters are painful, often intensely so, and they eventually crust over and heal in two to four weeks.
Impetigo
Impetigo is a bacterial skin infection most common in children, and it has a very recognizable look. The nonbullous form produces thick, honey-colored crusts on the skin, often around the nose and mouth. The bullous form looks different: it causes large blisters filled with clear fluid. Both types are highly contagious and spread easily through direct contact or shared items like towels.
Pressure Sores
Pressure sores develop when sustained pressure cuts off blood flow to the skin, usually over bony areas like the heels, tailbone, or hips. Their appearance changes dramatically depending on severity.
In the earliest stage, the skin is still intact but shows a patch of redness that doesn’t fade when you press on it. On darker skin tones, this may appear as a change in color rather than obvious redness. At stage two, the top layer of skin breaks down, revealing a shallow open sore or blister with a red or pink wound bed. Stage three sores extend deeper through the skin into the fat layer underneath and may look like a crater, sometimes with dead tissue visible. At stage four, the damage is severe enough to expose bone, tendon, or muscle, and tunneling beneath the skin is common.
Sores That Won’t Heal
A sore that refuses to heal over several weeks deserves attention, because it can be a sign of skin cancer. Basal cell carcinoma, the most common type, often appears as a sore that bleeds, scabs over, and then reopens. On lighter skin, it may look like a shiny, somewhat translucent bump with a pearly white or pink appearance, sometimes with tiny visible blood vessels. On darker skin, it often appears as a brown or glossy black bump with a rolled border.
Other forms of basal cell carcinoma can look like a flat, scaly patch that grows slowly over time, or a white, waxy, scar-like area without a clear edge. A brown, black, or blue lesion with dark spots and a slightly raised, translucent border is another possible presentation. Any sore that cycles through bleeding and scabbing without fully healing over four weeks or more warrants a closer look.
Signs a Sore Is Infected
Regardless of what caused a sore, certain visual changes signal infection. Thick drainage that is white, yellow, or brown, sometimes with an unpleasant smell, indicates bacteria have entered the wound. Redness that spreads outward from the sore’s edges, rather than staying contained, is another warning sign. Increasing swelling, worsening pain, and warmth around the area all point toward infection. Red streaks extending away from the sore suggest the infection may be spreading along the lymphatic system, which needs prompt medical attention.
Healthy healing sores may produce small amounts of thin, clear fluid. That’s normal. The shift to cloudy, thick, or colored drainage is the visual dividing line between a sore that’s healing and one that needs treatment.