Scabs are a normal part of the body's healing process, and they can sometimes turn yellow as a wound heals. In other cases, yellow scabs can be a characteristic symptom of certain skin infections, such as impetigo and cold sores.

Although scabs are usually dark red, they can go through many color and texture changes while the wound is healing.

In this article, we look at the possible causes of yellow scabs and their treatment options.

a yellow scab on the a persons cheek. Image credit: Niels Olson, 2008 Share on Pinterest
Yellowish crusting can appear on a scab over time.
Image credit: Niels Olson, 2008

The skin acts as a barrier, protecting the body from harmful agents in the environment. When something injures the skin, blood will clot around the wound to form a temporary dry crust called a scab.

The body naturally forms scabs to seal the wound, preventing bleeding and reducing the risk of germs entering the skin.

Scabs are usually a dark red or brown color initially, and they often get darker during the healing process. However, in some people, a scab may lose color and turn lighter over time instead.

Yellowish crusting can form on a scab when pus builds up. Pus is usually a sign of infection, and it can indicate either a bacterial infection, such as impetigo, or a viral infection, such as herpes.

Sometimes, the scab can crack, and a small amount of clear yellow or pink fluid can ooze out. Usually, this is normal and not a cause for concern. However, a person should be sure to keep the area clean and dry.

Sometimes, the immune system cannot fight off all the bacteria that gets into a wound, and this can lead to an infection.

Some of the signs of an infected wound are:

  • an expanding area of redness around the wound
  • pus or cloudy fluid coming from the wound
  • swelling, tenderness, or pain around the wound that gets worse rather than better with time
  • a fever
  • yellowish crusting on the wound

Impetigo is a skin infection that can develop following any skin injury. It happens when bacteria get into a wound, such as a cut, or an area of eczema where the skin has cracked or broken. A person with impetigo will experience yellowish crusting on the skin, which will typically ooze.

Children sometimes get impetigo when a persistent runny nose causes irritation of the skin that results in infection.

Impetigo is rarely serious, but it is contagious. If a person scratches or touches the infected area, they may spread the germs around the body or to other people.

The herpes simplex virus (HSV) causes cold sores, which usually appear around the lips.

A cold sore will often begin as a tingling, itching, or burning sensation in the affected area. This sensation can last for several hours to a day, after which a cluster of red, fluid filled blisters will appear. These blisters can appear more cloudy over time, and the fluid may resemble pus.

The blisters usually break open after several days and weep a clear or yellow liquid. Outbreaks can be painful and tend to last for about a week.

In the final stage, the blisters scab over. These scabs, which are sometimes yellow, tend to dry up and fall off within several days.

In otherwise healthy people, wounds such as cuts, scrapes, and grazes will get better on their own as long as a person keeps them clean.

If someone thinks that they have an infected wound, they should speak to a doctor. The doctor will usually prescribe a course of oral antibiotics or an antibiotic cream or ointment, depending on the severity and extent of the infection.

Treating impetigo

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A doctor may prescribe oral antibiotics to treat an infected wound.

Doctors also treat impetigo with oral or topical antibiotics. As impetigo is contagious, an infected child should not go to school for a few days after the treatment has started.

Impetigo usually clears on its own within a few weeks.

The American Academy of Dermatology advise people to manage the infection by:

  • cleaning the sores with soap and water as often as the doctor recommends
  • avoiding skin-to-skin contact until the blisters crust over or the person has taken antibiotics for 1 to 2 days
  • covering sores with gauze bandages and tape
  • avoiding touching or scratching the sores
  • using a new washcloth each time

Treating a cold sore

There is no cure for cold sores. Once someone has contracted HSV, they are likely to develop a cold sore every so often for the rest of their life. Factors including illness, stress, and skin injury can all trigger an outbreak.

Docosanol (Abreva) is an over-the-counter topical medication that people can use to treat an outbreak when there are signs that it is beginning. This medication works by fighting the virus.

Oral antiviral medications are also available by prescription to treat outbreaks and, if a doctor deems it necessary, prevent further outbreaks.

Scabs are a normal part of the skin's healing process. They stop bacteria from getting into the wound while the immune system repairs the tissue underneath.

Scabs are usually a dark red color, and they tend to get darker before drying up and falling off. When there is crusting around the scab, and it appears yellow, it is possible that the area has become infected and needs treatment with antibiotics. Anyone who thinks that they have an infected wound should speak to a doctor.

Impetigo and cold sores are two common conditions that can also cause yellow scabs. People may need antibiotics to treat impetigo, but it is often possible to manage cold sores at home.