A foot infection typically shows some combination of redness, swelling, warmth, and pain, but the specific appearance varies widely depending on whether the cause is bacterial, fungal, or viral. Some infections look like a spreading patch of pink or red skin, others show up as peeling and cracking between the toes, and more serious ones can produce pus, open sores, or red streaks traveling up the leg. Knowing what to look for helps you figure out what you’re dealing with and how urgently you need to act.
Bacterial Skin Infections
The most common bacterial foot infection is cellulitis, which happens when bacteria enter through a crack, cut, or break in the skin. It appears as a poorly defined area of redness that feels warm and swollen to the touch. Unlike a clear-bordered rash, cellulitis tends to be pink or red with blurry, spreading edges that expand outward over hours or days. The skin is tender when you press on it, and the affected area can feel tight or stretched because of the underlying swelling.
As cellulitis progresses, the swelling can become severe enough to create small fluid-filled blisters on the surface, or give the skin a dimpled, orange-peel texture where it puckers around hair follicles. You might also notice the skin looking shiny or glazed. A related but more superficial infection called erysipelas looks similar but has sharper, more clearly defined borders and a brighter red color compared to the flatter pink of cellulitis.
Fungal Infections
Athlete’s foot is extremely common and comes in three distinct patterns, each with a different look.
Interdigital is the most frequent type. It shows up as peeling, white, soggy-looking skin in the web spaces between your toes, most often between the fourth and fifth toes. The surrounding skin may be red with silvery-white scaling. Cracks or fissures can develop in the creases, which burn or sting, especially when the area gets wet.
Moccasin-type covers the sole, heel, and sides of the foot in a pattern that matches the outline of a moccasin shoe. It looks like dry, thick, scaly skin with a border of peeling along the edges of the foot. This type is often mistaken for plain dry skin because it develops slowly and is usually not very itchy. It tends to be chronic and harder to get rid of than other forms.
Vesicular is the least common but most dramatic. It produces intensely itchy clusters of small blisters, typically on the arch or inner sole of the foot. The blisters are 1 to 3 millimeters across and sit on a base of red, inflamed skin. When they rupture, they leave behind a raw, oozing surface. This type develops much faster than the other two forms.
Infected Toenails
An infection of the skin fold around a toenail, called paronychia, is easy to spot. The skin right next to the nail becomes red, puffy, and painful to touch. It feels warm compared to the surrounding skin. As pus builds up underneath, you may see a white or yellowish pocket forming at the base or side of the nail. This can develop after an ingrown toenail, a torn cuticle, or a minor injury to the nail area. In some cases, the nail itself changes color or lifts slightly from the nail bed.
Plantar Warts
Plantar warts are caused by a virus and grow on the sole of the foot, often on pressure points like the ball or heel. They look like small, rough, grainy bumps that are typically skin-colored or slightly gray. The key feature that distinguishes them from calluses or corns is the presence of tiny black dots scattered across the surface. Those dots are small clotted blood vessels. Warts also interrupt the normal lines and ridges of your skin, while calluses preserve them. Pressing on a wart from the sides tends to cause a sharp pinching pain, whereas pressing directly down on a callus hurts more.
Diabetic Foot Infections
People with diabetes face a unique and serious risk because nerve damage can reduce sensation in the feet. A diabetic foot ulcer often starts as a painless sore on the bottom of the foot, particularly under the ball of the foot or on the heel. These ulcers have a characteristic “punched-out” appearance with clean, defined edges surrounded by a ring of thick callus. Because neuropathy dulls pain, the ulcer can worsen without the person realizing it.
Signs that a diabetic foot ulcer has become infected include drainage that is cloudy, yellowish, or foul-smelling, along with redness and swelling spreading beyond the wound edges. The drainage may be watery (serous), bloody, or thick and pus-like. Other warning signs to watch for include skin that looks blue, mottled, or unusually pale around the wound, cracked or fissured skin nearby, and darkened or blackened tissue at the edges. If a wound probes deep enough to touch bone or hasn’t healed after weeks of care, a deeper bone infection may be developing. Bone infection in the foot causes persistent, localized swelling and warmth over the affected area.
How to Tell Infection From Normal Inflammation
Any cut, scrape, or surgical wound on the foot will show some redness, swelling, and warmth as it heals. That’s normal inflammation. The line between healing and infection comes down to a few specific signs. Infection is typically diagnosed when you see thick, cloudy pus draining from the wound, or when at least two of the following are present: redness spreading beyond the wound’s edges, increasing swelling, the area feeling hot to the touch, or pain that is getting worse rather than improving over time.
The key word is “increasing.” A healing wound gradually improves day by day. An infected wound gets progressively redder, more swollen, and more painful. If you’re unsure, trace the edge of the redness with a pen and check again in a few hours. If it has expanded past the line, that suggests spreading infection rather than routine healing.
Signs the Infection Is Spreading
Red streaks traveling from the infected area up toward your ankle or leg are a hallmark sign that infection has entered the lymphatic system. These streaks follow the path of lymph vessels under the skin and indicate the infection is no longer contained locally. This requires prompt medical attention.
Signs that a foot infection has triggered a bodywide response include a fast heart rate, rapid breathing, fever or abnormally low body temperature, confusion, and extreme discomfort that seems out of proportion to the wound itself. Low blood pressure and shortness of breath are particularly concerning. These are signs of sepsis, especially in someone with an existing wound or a condition like diabetes that affects immune function.
What Improvement Looks Like
Once you start treatment for a bacterial foot infection, visible improvement generally takes 7 to 14 days. The signs that things are getting better include reduced redness, less swelling, the area no longer feeling hot, decreasing pain, and less or no pus draining from the wound. You won’t see dramatic changes overnight. A slow, steady reduction in all of these signs over the first week or two is what to expect. If the infection looks the same or worse after several days of treatment, that’s worth following up on, as it may indicate the treatment needs to be adjusted or the infection is deeper than initially thought.