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Skin Glossary · Appearance of the skin

Scab (Eschar)

Related terms · Scab · Yellow crust

A crust refers to a scab dried on the skin surface. Rather than just color and thickness, we examine what has dried and whether there is pain, heat, or spreading.

Reviewed by Korean Medicine Doctor Choi Yeon-seung · Last updated 2026-08-25
01

What does 'scab' (gapi) mean?

A scab is a crust formed when exudate, blood, or pus dries on the skin surface. Rather than just the color and thickness, we look at what has dried and whether there is pain, heat, or spreading.

02

How is it different from similar conditions?

Scaling is the shedding of dry keratin, whereas a scab is a change caused by liquid components drying on the skin.

03

Why is this important in skin care?

Scabs can occur after exudation from eczema and can also be a clue to an infection.

04

What should be checked based on my symptoms?

Do not force them off; if yellow scabs spread or if you experience pain and heat, seek prompt medical evaluation.

Related conditions and medical guidance

Check guides where this term is used

Condition GuidanceAtopic DermatitisAtopic dermatitis is not confirmed by a single blood test or allergy test. In dermatology, the process centers on observing the appearance and distribution of dryness, itching, and rashes, as well as inquiring about the onset, the course of improvement and worsening, sleep disturbance, response to previous treatments, and exposure to irritants such as soap, detergents, scented products, and smoke. Medical history of atopic dermatitis, asthma, or hay fever for yourself and your family is also reviewed. In many cases, a physical skin examination and medical history are sufficient; blood tests or skin biopsies are selected when other causes of rashes must be ruled out. Symptoms, distribution, and progression are interpreted together rather than relying on a single test result.Condition GuidanceEczemaCommon symptoms of eczema include dry, severely itchy skin and rashes. These can occur on the face, inside the elbows, behind the knees, and on the hands and feet; depending on skin tone, they may appear red, brown, purple, or gray, or present as prominent rough bumps. Scratching leads to more swelling and itching, and may cause scratch marks, scaling, cracking, blisters, oozing, or scabs. Prolonged scratching causes the skin to thicken and crack. If you experience unusual pain, heat, yellow scabs, or if clustered blisters are accompanied by fever and fatigue, promptly evaluate for the possibility of infection or herpetic eczema.Condition GuidanceFolliculitisFolliculitis typically appears as small red pimples or pus-filled pustules that suddenly form in clusters around the hair follicles. The area around the skin change may be red, itchy, or burning, and may be painful when pressed; scabs may form after pustules burst. Shallow folliculitis remains as small papules or pustules, but if it deepens, it may look like a large, hard, painful boil or a carbuncle where several boils are connected, increasing the risk of scarring and hair loss. If redness and pain spread suddenly or are accompanied by fever, chills, or body aches, the spreading infection must be promptly evaluated.Medical Evaluation GuideWhen oozing, pus, pain, and fever occur togetherIf there is rapidly spreading redness, pain that makes it difficult to touch, pus or yellow crusts, fever, or severe swelling around the eyes and mouth, we will first connect you to infection treatment or emergency evaluation. If you have difficulty breathing or if your lips or tongue swell, seek emergency help immediately. Once urgent issues are resolved, remaining itchiness and recurring symptoms will be managed through Korean medicine treatment.

Comparison of similar terms

Terms to know for easier distinction

Evidence and Update Information

The definitions and safety standards in the materials below were referenced.

  1. NCBI Clinical Methods: Principles of Skin Lesion ObservationClinical terms describing the shape, arrangement, and distribution of lesions have been verified.
Summary and review information for this page

Reviewing Medical Staff

Choi Yeon-seung, Doctor of Korean MedicineChief Director · Editor of Korean Medicine Atlas · BRC Researcher

Page Summary

A crust refers to a scab dried on the skin surface. Rather than just color and thickness, we examine what has dried and whether there is pain, heat, or spreading.

What this page covers

What is explained
In the sentence 'A scab refers to a crust dried on the skin surface. Rather than just the color and thickness, we look at what has dried and whether there is pain, heat, or spreading,' what should be checked first?
What situations are covered
A scab refers to a crust dried on the skin surface.
What distinctions are made
Meaning of scab: A crust formed when exudate, blood, or pus dries on the skin surface.
How should this be understood
Rather than just the color and thickness, we look at what has dried and whether there is pain, heat, or spreading.

Key Points

  • Meaning of scab: A crust formed when exudate, blood, or pus dries on the skin surface.
  • Difference from similar terms: Scaling is the shedding of dry keratin, whereas a scab is a change caused by liquid components drying on the skin.
  • Reason for checking during evaluation: Scabs can occur after exudation from eczema and can also be a clue to an infection.

References cited on this page

Skin Terminology Glossary

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