What Is a Scab on a Wound?

Medically Reviewed on 11/2/2021
what is a scab on a wound
A scab is a dry, rusty brown crust formed over a wound, formed by the process of coagulation to protect your body against infection, blood loss, and debris

A scab is a dry, rusty brown crust formed over a wound, formed by the process of coagulation to protect your body against infection, blood loss, and debris.

Scabs form a layer over a superficially or partially thick wound surface within 24 hours of injury and prevent further progression of the wound. Most of them fall off within a few days to weeks with the regeneration of underlying normal tissue.

How are scabs formed?

Scabs are one of the main indicators of tissue healing. When your skin is injured due to any form of injury such as cut or abrasion, there is bleeding due to leakage of blood flowing from the damaged vessels. This blood activates platelets, fibrin, and clotting factors in the blood that soon form a clot over injured surfaces to prevent further blood loss. 

The body's main repair system gets activated, and fibrin threads begin to form a mesh-like network that traps the blood cells within it. The outer surface of this meshwork of blood cells hardens as it dries to form a rusty brown crust, forming a clot (scab) that covers the underlying healing tissues like a cap

Scabs can be easily seen on the skin in the form of black and brown marks. They serve as a barrier to prevent the skin underneath from getting dehydrated or infected by germs. They are generally held in place firmly until the tissue underneath becomes fully repaired and new skin cells have appeared, after which they naturally fall off.

What causes scabs?

Scabs may be caused by injuries such as:

Diseases that cause scabbing include:

Scabs can lead to scarring and secondary bacterial infections in some cases.

What are the signs and symptoms of scabs?

Scabs may present along with other symptoms that affect the skin:

  • Bleeding or bruising
  • Burning feeling
  • Crusting itchy skin
  • Pain or soreness
  • Pus or discharge
  • Redness, warmth or swelling
  • Thickening of the skin
  • Tingling sensation

How to treat a scab

  • Always keep the scab area clean to prevent the risk of infection from debris and germs that may slow down the wound-healing process.
  • Wounds must be moist because it helps the skin heal quickly and speeds recovery. Moistening scabs or wounds can stop further progression of the wound into a bigger size and prevent itchiness and scarring.
  • A warm compress increases the blood flow to the wound and triggers skin regeneration.
  • A cold compress can reduce swelling and inflammation and provide itch relief if the scar is throbbing or itching.
  • Cover the scab with a bandage to prevent further irritation and minimize the risk of scraping it.


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Medically Reviewed on 11/2/2021
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