Carl R. Darnall Army Medical Center - Health Library

Epidermal Cyst

(Epidermoid Cyst; Epidermal Inclusion Cyst; Epithelial Cyst; Keratin Cyst)

Definition

An epidermal cyst is a type of slow-growing lump underneath the skin. This cyst contains soft, cheese-like skin contents. These usually appear on the face, neck, chest, upper back, genitals, or behind the ears. Similar cysts called pilar cysts often occur on the scalp.

Causes ^

Causes include:

  • Blockage of a hair follicle by skin cells—When an injury to the skin occurs, cells from the surface may block hair follicles located deeper within the skin.
  • Damage to a hair follicle due to acne
  • Blockage or defect of the sebaceous gland—This gland is near the hair follicle. It secretes oily material used to lubricate the skin and hair.

Normal Skin Anatomy
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Risk Factors ^

Acne and skin injuries increase the risk of developing an epidermal cyst.

Symptoms ^

An epidermal cyst may cause:

  • Small, dome-shaped lump beneath the skin
  • Foul-smelling, cheese-like material draining from the cyst
  • Redness or tenderness on or around the cyst if it becomes inflamed or infected

Diagnosis ^

You will be asked about your symptoms and medical history. A physical exam will be done. In most cases, the diagnosis can be made by looking at it. You may be referred to a dermatologist. This is a doctor who specializes in skin disorders.

Treatment ^

Some epidermal cysts do not need treatment. If needed, treatment options may include the following:

  • Surgical excision—The doctor removes the entire cyst, including its contents and cyst wall.
  • Surgical drainage—This involves cutting open the cyst, and draining the contents. The cyst might come back, though.
  • Antibiotics—These may be prescribed if the cyst has become infected.

Prevention ^

There is no way to prevent an epidermal cyst. If any of the cyst wall is left behind after drainage, the cyst may come back. If this happens, the doctor may decide to remove the cyst using surgery.

RESOURCES:

American Academy of Dermatology
http://www.aad.org

Family Doctor–American Academy of Family Physicians
http://familydoctor.org

CANADIAN RESOURCES:

Canadian Dermatology Association
http://www.dermatology.ca

Health Canada
http://www.hc-sc.gc.ca

REFERENCES:

Common benign skin lesions. EBSCO DynaMed Plus website. Available at:http://www.dynamed.com/topics/dmp~AN~T908545/Common-benign-skin-lesions. Updated July 24, 2017. Accessed September 1, 2017.

Cysts. DermNet NZ website. Available at: http://dermnetnz.org/lesions/cysts.html. Updated February 2016. Accessed September 1, 2017.

Cysts—epidermoid and pilar. The British Association of Dermatologists website. Available at: http://www.bad.org.uk/for-the-public/patient-information-leaflets/cysts---epidermoid-and-pilar?q=Cysts - epidermoid and pilar. Accessed September 1, 2017.

Luba MC, Bangs SA, Mohler AM, Stulberg DL. Common benign skin tumors. Am Fam Physician. 2003;67(4):729-738.

Zuber TJ. Minimal excision technique for epidermal (sebaceous) cysts. Am Fam Physician. 2002;65(7):1409-1412.

Last reviewed September 2017 by EBSCO Medical Review Board James P. Cornell, MD  Last Updated: 9/2/2015