An infected cut typically shows five telltale signs: increasing redness that spreads beyond the wound edges, swelling, warmth around the area, worsening pain, and thick discharge that looks white, yellow, green, or brown. If your cut has one or two of these, it may be in the early stages of infection. If it has several, or if you develop a fever, the infection needs medical attention.
Not every sign of irritation means infection, though. Cuts naturally produce some redness, mild swelling, and clear or slightly tinted fluid as part of normal healing. The key is knowing what’s normal and what’s crossed the line.
Normal Healing vs. Early Infection
Every cut triggers inflammation as part of the healing process, so some redness and puffiness in the first day or two is expected. A healing wound also produces serous drainage, a thin, watery fluid that’s clear or slightly yellowish. This is your body cleaning the area and delivering repair cells to the site. It’s not pus, and it’s not a reason to worry.
Infection symptoms typically begin one to three days after bacteria enter the wound. The distinction between normal healing and infection comes down to direction: normal inflammation improves a little each day, while infection gets steadily worse. If redness is shrinking, swelling is going down, and pain is fading, your cut is healing. If those things are intensifying after the first 48 hours, infection is likely setting in.
The Five Signs of a Localized Infection
These are the classic indicators that bacteria have taken hold in a wound:
- Spreading redness. A thin pink border right at the wound edge is normal. Redness that fans outward, grows wider over hours, or develops a hot, angry look is not. Watch whether the red zone is expanding by marking its edge with a pen and checking again a few hours later.
- Increasing swelling. Mild puffiness around a fresh cut is part of the inflammatory response. Swelling that gets worse after the first day or two, or that makes the skin feel tight and stretched, suggests infection.
- Heat. Place the back of your hand over the skin near the cut, then compare it to the same spot on the other side of your body. Infected tissue feels noticeably warmer.
- Worsening pain. Pain from a clean cut peaks in the first few hours and then gradually fades. If the area becomes more tender or throbs days later, that’s a warning sign.
- Pus or foul-smelling discharge. Thick, milky drainage that’s white, yellow, green, pink, or brown is pus. It usually smells bad. This is the most definitive visual sign of infection and distinguishes an infected wound from one that’s simply irritated.
You don’t need all five to have an infection. Pus alone is enough to confirm one. Redness plus increasing pain is enough to suspect one. Trust the overall trajectory: things should be getting better, not worse.
What the Wound Bed Looks Like
If your cut is deep enough to see the tissue inside, its color tells you a lot. Healthy healing tissue (called granulation tissue) is moist, bumpy, and pink or red, with a slightly shiny appearance. That bright redness means good blood flow and active repair.
Infected or poorly healing tissue looks different. Dark, dusky granulation that’s lost its red color can signal poor blood flow or infection. Slough, a stringy or slimy layer sitting on the wound surface, is another concern. Slough ranges from white (mild bacterial presence) to yellow or green (heavier bacterial counts) to brown. If you see a yellow-green film or stringy material in your wound that wasn’t there before, bacteria are gaining ground.
Signs the Infection Is Spreading
A localized infection sits at the wound site. A spreading infection moves into surrounding tissue or the bloodstream, and the warning signs shift from local to whole-body.
Red streaks extending away from the wound toward your torso are one of the most urgent signs. These streaks follow lymphatic channels and mean bacteria are traveling through your system. This requires same-day medical care.
Fever is the other major red flag. A temperature of 103°F (39.4°C) or higher warrants immediate medical attention regardless of the cause. But even a lower-grade fever combined with a worsening wound is significant. Other systemic signs include chills or shaking, rapid heart rate, fast breathing, unusual fatigue, confusion, and warm or clammy skin. These can indicate sepsis, a dangerous escalation where the body’s response to infection starts damaging its own organs. A high heart rate, confusion, or rapid breathing can be early signs that a simple wound infection has become something more serious.
Cuts That Carry Higher Risk
Some wounds are more likely to get infected than others. Puncture wounds (stepping on a nail, for example) push bacteria deep into tissue where oxygen is low and cleaning is difficult. Animal and human bites introduce bacteria from saliva directly into the wound. Cuts contaminated with soil, rust, or debris carry more organisms than a clean kitchen knife cut. And wounds on the hands and feet tend to get infected more often simply because those areas contact more surfaces throughout the day.
Your own health matters too. Diabetes, immune-suppressing medications, poor circulation, and chronic conditions that slow healing all raise your infection risk. If you fall into any of these categories, take even mild signs of infection seriously rather than waiting to see if they resolve.
Tetanus is a separate concern from a typical bacterial wound infection, but it’s worth checking your vaccination status after any dirty or deep cut. If you’ve completed your tetanus vaccine series and your last shot was less than five years ago, you’re covered regardless of wound type. For clean, minor wounds, a booster is recommended if your last shot was 10 or more years ago. For dirty or major wounds, that window tightens to five years. If you’re unsure of your vaccination history, a booster is recommended for any wound.
What to Do if You Suspect Infection
Mild, early signs (slight increase in redness, minor swelling without pus) can sometimes be managed at home for 24 hours while you monitor the trajectory. Clean the wound gently with running water, apply a thin layer of antibiotic ointment, and cover it with a clean bandage. Check it twice a day. If the redness is shrinking and the pain is easing, you’re likely in the clear.
If you see pus, if the redness is expanding, if the wound smells bad, or if the pain is getting worse rather than better, it’s time to see a healthcare provider. Most wound infections are treated with oral antibiotics and clear up within a week or two. Some deeper infections need the wound opened and drained, which sounds unpleasant but provides fast relief because it removes the pocket of bacteria causing the problem.
Red streaks, fever above 103°F, rapid heartbeat, confusion, or chills alongside a wound need urgent care. These symptoms can progress quickly, and early treatment makes a significant difference in outcomes.