by EBSCO Medical Review Board
(Epidermoid Cyst; Epidermal Inclusion Cyst; Epithelial Cyst; Keratin Cyst)


An epidermal cyst is a lump under the skin. It has soft, yellow matter inside. They often happen on the face, neck, chest, upper back, genitals, or behind the ears.


It may be caused by:

  • Blockage of a hair follicle by skin cells due to a skin injury
  • Damage to a hair follicle due to acne
Normal Skin Anatomy
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Risk Factors

Acne and skin injuries raise the risk of this type of cyst.


Problems may be:

  • Small, dome-shaped lump beneath the skin
  • Foul-smelling, cheese-like material that may drain from the cyst
  • Redness or pain on or around the cyst


You will be asked about your symptoms and health history. A physical exam will be done. This is often enough to make the diagnosis. You may be sent to a doctor who treats skin problems.


The cyst may go away on its own. It may need to be treated when it causes problems. This can be done with:

  • Surgery to remove the entire cyst, including its contents and cyst wall
  • Incision and drainage to remove the cyst contents, though it may return in time

Antibiotics may be given to treat infection.


There is no way to prevent an epidermal cyst.


American Academy of Dermatology 

Family Doctor–American Academy of Family Physicians 


Canadian Dermatology Association 

Health Canada 


Common benign skin lesions. EBSCO DynaMed website. Available at: . Updated February 5, 2018. Accessed November 25, 2019.

Cysts. DermNet NZ website. Available at: Updated February 2016. Accessed November 25, 2019.

Moreno-Ramírez D, Ruiz-Villaverde R, et al. A. process of care for patients with benign cysts and tumors: Consensus document of the Andalusian Regional Section of the Spanish Academy of Dermatology and Venereology (AEDV). Actas Dermosifiliogr. 2016 Jun;107(5):391-399.

Revision Information

  • Reviewer: EBSCO Medical Review Board James P. Cornell, MD
  • Review Date: 09/2019
  • Update Date: 07/28/2020