How to Treat an Infected Cut: Signs, Steps, and When to See a Doctor

A cut that should be healing is suddenly redder, warmer, and more tender than it was yesterday. Maybe there's a little pus, or the skin around it is starting to swell. It's unsettling, and you're not sure whether to keep watching it or pick up the phone.

Here's the reassuring part: most cuts heal cleanly with simple care, and even an early infection often settles down quickly once you treat it right. The key is knowing what an infected cut actually looks like, what to do at home, and the specific warning signs that mean it's time to get medical help.

How to tell if a cut is infected

A healing cut is usually a little pink and mildly tender for a day or two, then steadily improves. An infected cut moves in the opposite direction: it gets worse instead of better. Watch the area over a day or two rather than a single moment, since the trend matters more than a snapshot.

According to the American Academy of Dermatology, the main signs that a cut is infected are pus, or increasing redness, swelling, or pain around the wound. If those are growing instead of fading, treat it as an infection.

• Pus or cloudy drainage coming from the cut
• Redness that is spreading or deepening
• Swelling and warmth around the wound
• Pain that is increasing rather than easing
• A wound that simply won't heal as expected

How to treat a cut at home and prevent infection

The best treatment for an infected cut starts with the same careful wound care that prevents infection in the first place. The American Academy of Dermatology and Mayo Clinic both recommend a simple, consistent routine.

One detail surprises a lot of people: dermatologists advise against routinely reaching for an antibiotic cream. The AAD specifically recommends NOT using topical antibiotics on a minor cut, because antibiotic ointments can irritate the skin. Instead, apply plain petroleum jelly to keep the wound moist, since moist wounds heal faster than those that form a dry scab.

• Wash your hands first with soap and water
• Gently clean the cut with cool or lukewarm water and mild soap
• Stop any bleeding with gentle pressure using a clean cloth
• Apply petroleum jelly to keep the surface moist (skip antibiotic creams)
• Cover with a clean, sterile bandage and change it daily

How long does an infected cut take to heal?

Most minor cuts heal within about one week with good care. If yours is staying red, painful, or draining well beyond that window, the infection likely needs more than home care.

When a cut becomes infected, the timeline depends on how far the infection has spread. A mild, surface-level infection often improves within days of cleaning it up and keeping it covered. But if bacteria spread into the deeper skin, you may develop cellulitis, which usually requires a prescription. Mayo Clinic notes that cellulitis is typically treated with an oral antibiotic for 5 to 10 days, and the full course should be finished even after the skin looks better.

When to see a doctor about an infected cut

Some cuts need professional care from the start, and some infections need urgent attention. The American Academy of Dermatology recommends seeing a doctor or dermatologist if a cut is longer than 3/4 inch, deeper than 1/4 inch, won't stop bleeding, or shows signs of infection such as pus or growing redness, swelling, or pain.

Certain symptoms are red flags that an infection may be spreading through the body and need same-day or emergency care. Cellulitis can become serious quickly, so don't wait it out if you notice the following.

• A fever above 100.4°F (38°C), chills, sweats, body aches, or fatigue
• A red streak spreading outward from the wound
• Skin that is increasingly red, hot, swollen, and painful
• An infection that keeps getting worse despite home care
• A cut from a dirty or rusty object if your tetanus shot isn't current

Why doctors lean on antiseptics, not antibiotics

It can feel counterintuitive to skip the antibiotic ointment, but there's a strong reason behind it. Overusing antibiotics, including topical ones, has helped drive antibiotic resistance. The share of Staphylococcus aureus infections that were resistant (MRSA) rose from about 2% in 1974 to 22% in 1995, and roughly 63% by 2004.

Because of this, dermatology guidance now favors meticulous wound care and antiseptics over routine topical antibiotics for minor wounds, reserving prescription antibiotics for infections that genuinely need them. The CDC adds that the simplest protection is also the most effective: keep cuts clean and covered with a clean, dry bandage until fully healed, wash your hands after changing bandages, and never pick at or pop sores, because the pus can contain MRSA.