Signs of Foot Infection: Symptoms & Red Flags

If your foot is red, swollen, or just “not right,” it’s easy to hope it will get better on its own. But foot infections can spread quickly, especially if you have diabetes, poor circulation, or fragile skin. Catching problems early can be the difference between a short course of antibiotics and serious complications.

This guide walks through the key signs of foot infection, what they look and feel like, and when they’re an emergency rather than a “wait and see” issue.

This article is for general education and can’t replace medical advice. If you think you might have a foot infection, especially with diabetes or circulation problems, seek care promptly.

1. What is a foot infection?

A foot infection happens when germs (usually bacteria, sometimes fungi) enter through a break in the skin—anything from a blister or cracked heel to a puncture wound or ulcer. Once inside, they trigger inflammation and can spread into deeper tissues, causing cellulitis, abscesses, or bone infection (osteomyelitis).

Foot infections often start from:

• Cuts, scrapes, or puncture wounds
• Blisters from tight shoes
• Ingrown toenails
• Cracks in dry heels or between the toes
• Diabetic foot ulcers or pressure sores

Any break in the skin is a potential entry point.

2. Early local signs of foot infection

Most infections begin with local symptoms around the wound or affected area. Classic signs include changes in colour, temperature, swelling, pain and drainage.

2.1 Redness that’s spreading

A small rim of pink right around a fresh wound can be part of normal healing. Infection is more likely when you see:

• Redness that spreads outward from the wound
• A more intense, “angry” red colour
• Irregular borders rather than a neat circle

In cellulitis (a common bacterial skin infection), the redness may expand over hours to days and feel warm or hot to the touch.

2.2 Warmth and swelling

Infected tissue often feels:

• Warmer than the surrounding skin
• Swollen or puffy, especially around the wound, toes, or ankle

This warmth and swelling come from increased blood flow and fluid as your immune system reacts to the bacteria.

2.3 Pain or tenderness that’s getting worse

A small wound may hurt a bit at first and then gradually improve. Infection is more likely when:

• Pain is increasing instead of decreasing
• The area feels tender even to light touch or pressure
• There’s a new throbbing or deep ache

In people with diabetic neuropathy, this sign can be blunted or absent—more on that below.

2.4 Drainage: pus, cloudy fluid, or bad smell

A bit of clear or slightly blood-tinged fluid can be normal early on. Signs more suggestive of infection include:

• Thick yellow, green or cloudy discharge
• Fluid that smells unpleasant
• New drainage soaking through dressings when there was little before

Drainage alone doesn’t always mean severe infection, but combined with other signs (pain, fever, spreading redness), it’s a red flag.

2.5 Skin changes around the wound

Look not just at the wound itself but the surrounding skin:

• Shiny, tight, or “stretched” skin over the top of the foot or around the ankle
• Skin that turns very pale, bluish, or dark (a late worrying sign)
• New blisters, breakdown, or blackened areas near a sore

These can indicate worsening inflammation, poor blood flow, or tissue damage.

3. Systemic (whole-body) signs of foot infection

When infection progresses, it can trigger whole-body symptoms, meaning the bacteria or inflammatory response is no longer “staying local.”

Common systemic warning signs include:

• Fever, chills, or night sweats
• Feeling very tired, weak, or “flu-like”
• Loss of appetite, nausea
• Fast heart rate

Systemic symptoms plus a suspicious foot wound mean you should seek urgent medical attention, especially in older adults or anyone with diabetes, immune compromise, or vascular disease.

4. Special situation: foot infection in people with diabetes

For people with diabetes, foot infections are particularly dangerous—and often harder to recognize. Neuropathy (nerve damage) and poor circulation can mask pain and slow healing, allowing an infection to progress quietly.

4.1 Signs can be subtle or painless

Instead of obvious pain, diabetes-related foot infections may show:

• A sore, blister, or ulcer that doesn’t heal within 1–2 weeks
• New or increasing drainage from a callus, corn, or ulcer
• Swelling of a toe or the whole foot without clear injury
• Skin that’s warmer on one toe or area compared to the other foot
• A foul odour from a dressing or wound
• An ulcer where bone can be felt with a cotton swab (possible osteomyelitis)

Because pain may be minimal or absent, any open sore on a diabetic foot should be treated as a big deal until a professional rules out infection.

4.2 When people with diabetes should call the doctor immediately

People with diabetes should seek prompt care if they notice:

• A blister, cut, or ulcer that doesn’t begin to heal in a few days
• New redness, warmth, or swelling around an existing sore
• Any drainage, especially if it’s thick or smelly
• A wound that exposes deeper tissue or bone
• Fever or feeling unwell along with a foot sore

Waiting “to see if it gets better” is risky in this group; infections can progress rapidly and increase the risk of hospitalization and amputation.

5. Types of foot infections and what they look like

Several different infections can affect the foot; many share overlapping signs.

5.1 Cellulitis

Cellulitis is a bacterial infection of the skin and the tissue just beneath it. On the foot, it often appears as:

• Spreading redness, warmth, and swelling
• Skin that may look shiny or tight
• Pain or tenderness
• Sometimes blisters or small areas of pus

It can develop from something as small as a cracked heel or a puncture wound.

For more detail on how cellulitis starts and how it’s treated, see the patient information from Mayo Clinic on cellulitis.

5.2 Infected wounds or ulcers

An existing wound, ulcer or surgical incision can become infected if bacteria get in. Typical signs include:

• Wound edges that look ragged, inflamed, or more red than before
• Increasing drainage or pus
• Tissue that looks grey, yellow, or dead (slough)
• Wound getting deeper or wider instead of smaller

In diabetes, infected ulcers often occur on pressure points—under the big toe, ball of the foot, or heel.

5.3 Toe and nail-bed infections

Around the toes and nails, infections might come from ingrown toenails or fungal nails that crack and let bacteria in. Signs include:

• Red, tender skin along the nail edge (paronychia)
• Swollen, painful toe
• Pus at the side of the nail
• Sometimes thick, discolored nail with secondary infection

5.4 Fungal infections that set the stage

While athlete’s foot itself is fungal and not a bacterial infection, the cracks and peeling skin between toes create perfect entry points for bacteria. Red, itchy, scaly skin should be treated promptly to prevent secondary infection.

6. When is a foot infection an emergency?

Some signs mean you should seek urgent or emergency care rather than waiting for a routine appointment:

• Rapidly spreading redness or swelling
• Severe pain, especially out of proportion to how the skin looks
• Red streaks moving up the foot or leg
• Black, blue, or very pale skin around a wound
• Large amounts of pus or foul-smelling drainage
• Fever, chills, or feeling very unwell
• Any sign of infection in a person with diabetes, poor circulation, or immune suppression

If you’re unsure, it’s safer to be checked and told “it’s okay” than to stay home while an infection worsens.

7. What you can (and shouldn’t) do at home

For minor, early infections in otherwise healthy people, home care may be part of the plan—but always in line with a clinician’s advice.

7.1 Good basic wound care

• Clean the area gently with clean water or saline; avoid harsh scrubbing.
• Dry the surrounding skin carefully, especially between toes.
• Apply a simple, appropriate dressing to protect the area and maintain a slightly moist healing environment (not soaking wet).
• Change dressings as recommended; watch for increased redness, pain, or drainage.

If you’re unsure why most modern guidelines prefer moist wound care over “airing it out,” we explain the pros and cons in our overview of dry versus moist wound healing.

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7.2 Things to avoid

• Do not start old or leftover antibiotics without medical guidance.
• Don’t use tight bandages that could cut off circulation—swelling can make this worse.
• Don’t repeatedly soak the foot in very hot water or strong antiseptics; this can damage healthy skin.
• Don’t ignore a wound that seems stalled or is getting slightly worse each day.

If home treatment doesn’t lead to clear improvement within 24–48 hours—or if you belong to a higher-risk group (diabetes, vascular disease, immune problems)—it’s time to see a professional.

8. How to lower your risk of foot infections

You can’t avoid every scratch or blister, but you can shrink the chances that a small problem turns into a big one.

8.1 Daily foot checks

Daily checks are especially important if you have diabetes or neuropathy:

• Look at the tops, sides, soles, and between toes every day.
• Use a mirror or ask for help if you can’t see the bottoms of your feet.
• Watch for new redness, swelling, blisters, cuts, or colour changes.

8.2 Foot hygiene and skin care

• Wash feet daily with lukewarm water and mild soap; dry carefully, especially between toes.
• Moisturize dry areas (but not between toes) to reduce cracking.
• Treat athlete’s foot or fungal toenails early.

For more everyday habits that support your body’s repair process, you can also read our guide to helping wounds heal faster naturally.

8.3 Shoes and nail care

• Choose well-fitting shoes with room for toes; avoid high heels and narrow toe boxes for long periods.
• Wear socks that wick moisture away.
• Cut nails straight across; don’t dig deep into the corners (this can cause ingrown nails).

8.4 Manage underlying conditions

Good blood sugar control, circulation health, and immune health all lower infection risk:

• Work with your healthcare team to manage diabetes, blood pressure, and cholesterol.
• Don’t smoke; smoking impairs circulation and healing.
• Keep regular check-ups with a podiatrist if you have diabetes or previous foot problems.

9. Key takeaways

• Common early signs of foot infection include spreading redness, warmth, swelling, increasing pain, and drainage (especially thick or foul-smelling).
• Whole-body signs like fever, chills, or feeling very unwell mean infection may be spreading and need urgent attention.
• People with diabetes may not feel pain, so any new sore, drainage, or colour change is important, even if it doesn’t hurt.
• Early evaluation and treatment can prevent serious complications, including hospitalization and amputation.
• When in doubt, especially if you have underlying health issues, it’s always safer to have a foot problem checked sooner rather than later.

Your feet carry you everywhere—checking them regularly and respecting the early signs of infection is one of the best investments you can make in your long-term health.