A scab that oozes pus, has a foul smell, or is discolored may be infected. You should clean the area, avoid touching it, and protect it with a sterile bandage. If the symptoms worsen, you should see a doctor.

A scab is your body’s protective response to a cut, scrape, bite, or other skin injury. Special blood cells called platelets form a clot at the injury. These cells act like a bandage to stop bleeding and keep out germs and debris. As the clot dries, it forms a scab.

Your skin is healing its wound under the protection of the crusty scab.

Scabs usually heal on their own. But a scab can become infected if bacteria get under the scab and into the wound.

It’s normal to have a little pink or reddish skin around the edge of your scab.

It’s also normal to have a little swelling around the scab, especially if you had stitches for the injury.

There are several ways to tell whether a scab may be infected:

  • Redness and swelling around the scab increase 48 hours after your injury.
  • Scab feels hot or painful.
  • Pus is oozing from the wound.
  • Scab bleeds when touched.
  • Wound smells foul.
  • Red streaks on the skin are coming from the wound.
  • Scab isn’t healing after 10 days.
  • Skin near the scab becomes discolored.
  • Area around the wound is yellow and crusty.
  • Pimple forms on the wound.
  • New tissue around the wound is forming abnormally.
  • Lymph node near the wound is swollen.
  • You have a fever with no other infection present.

Your scab can become infected when bacteria or other microorganisms enter the wound. This can happen in several ways:

  • Your wound wasn’t completely cleaned, and dirt and debris were still present.
  • You scratch or pick the scab and introduce new bacteria into the wound.
  • Your wound isn’t protected with a bandage.
  • Your wound has gotten too wet, making it more susceptible to fungal infections.

The most common types of bacteria causing skin infections are Staphylococcus (staph infection) and Streptococcus (strep infection). These bacteria are normally found on your skin in small numbers. During an infection their numbers increase.

The first line of treatment for any cut, bite, or skin injury is to keep the area clean.

For a scab that you think is becoming infected, home treatments include:

  • Clean the area with warm, soapy water three times a day and pat it dry with a clean towel.
  • Cover the scab with a sterile bandage.
  • Avoid picking or squeezing the scab.

Watch for other signs that an infection is developing, such as increasing size, worsening pain, drainage, or bleeding.

A fever of more than 100.4°F can be a sign the infection is spreading. It’s important to see a doctor right away if this occurs.

If the scab infection seems to be getting worse after 48 hours, see a doctor. If you have a sudden fever and other symptoms, like spreading redness or significant swelling around the wound, see a doctor right away.

It’s also important to visit your doctor with any signs of infection if you have diabetes, cancer, or other medical conditions that affect your immune system.

Most wound infections are easily treatable, but some can become serious and possibly life-threatening depending on the scab’s severity and location, as well as your underlying health.

To prevent a scab from becoming infected, keep the scab area clean and consider the following tips:

  • Wash the area with mild soap and water every day.
  • Keep it moist with a thin layer of petroleum jelly for the first several days.
  • Cover the area with a sterile bandage, unless it’s a minor cut or scrape.
  • Change the bandage every day.
  • Don’t scratch or pick at the scab.
  • Follow your doctor’s instructions if you’ve had stitches for the injury.
  • Talk to your doctor about a tetanus shot if the wound is a result of a burn, bite, or other significant injury.

Scab formation is your body’s protective response to cuts, scrapes, bites, and other skin injuries.

If you keep the area clean, it’s not likely to become infected. Home treatments with good wound care can usually stop an infection in an early stage. If your wound isn’t getting better, see your doctor.