Sebaceous cyst
Epidermal cyst; Keratin cyst; Epidermoid cyst; Epidermal inclusion cyst
A sebaceous cyst is a closed sac under the skin filled with a cheese-like or oily material.
Causes
Sebaceous cysts most often arise from swollen hair follicles. Skin injury can also cause a cyst to form. A sac of cells is created into which a protein called keratin is secreted. People with these cysts may have family members who also have them.
Symptoms
The main symptom is usually a small, non-painful lump beneath the skin. The lump is usually found on the face, neck, and trunk. It usually grows slowly and is not painful.
If the lump becomes infected or inflamed, other symptoms may include:
- Skin redness
- Tender or sore skin
- Warm skin in the affected area
- Grayish-white, cheesy, foul-smelling material that drains from the cyst
Exams and Tests
In most cases, the health care provider can make a diagnosis by examining your skin. Sometimes, a biopsy may be needed to rule out other conditions. If infection is suspected, you may need to have a skin culture .
Biopsy
A skin lesion biopsy is when a small amount of skin is removed so it can be examined. The skin is tested to look for skin conditions or diseases. A...
Skin culture
A skin or nail culture is a laboratory test to look for and identify germs that cause problems with the skin or nails. It is called a mucosal culture...
Treatment
Sebaceous cysts are not dangerous. Your provider may suggest home care by placing a warm moist cloth (compress) over the area to help the cyst drain and heal.
A cyst may need further treatment if it becomes:
- Inflamed and swollen – the provider may inject the cyst with steroid medicine
- Swollen, tender, or large – the provider may drain the cyst or do surgery to remove it
- Infected – you may be prescribed antibiotics to take by mouth
Possible Complications
Cysts may become infected and form painful abscesses .
Abscesses
An abscess is a collection of pus in any part of the body. In most cases, the area around an abscess is swollen and inflamed.
Cysts may return if they are not completely removed by surgery.
When to Contact a Medical Professional
Call your provider if you notice any new growths on your body. Although cysts are not dangerous, your provider should examine you for signs of skin cancer. Some skin cancers look like cystic nodules, so have any new lump examined by your provider.
References
Patterson JW. Cysts, sinuses, and pits. In: Patterson JW. Weedon's Skin Pathology. 4th ed. Philadelphia, PA: Elsevier; 2015:chap 16.
Stone MS. Cysts. In: Bolognia JL, Jorizzo JL, Schaffer JV, eds.
Dermatology
. 3rd ed. Philadelphia, PA: Elsevier Saunders; 2012:chap 110.
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Hair follicle anatomy - illustration
At the base of the hair follicle are sensory nerve fibers that wrap around each hair bulb. Bending the hair stimulates the nerve endings allowing a person to feel that the hair has been moved. One of the main functions of hair is to act as a sensitive touch receptor. Sebaceous glands are also associated with each hair follicle that produce an oily secretion to help condition the hair and surrounding skin.
Hair follicle anatomy
illustration
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Hair follicle anatomy - illustration
At the base of the hair follicle are sensory nerve fibers that wrap around each hair bulb. Bending the hair stimulates the nerve endings allowing a person to feel that the hair has been moved. One of the main functions of hair is to act as a sensitive touch receptor. Sebaceous glands are also associated with each hair follicle that produce an oily secretion to help condition the hair and surrounding skin.
Hair follicle anatomy
illustration
Review Date: 4/14/2015
Reviewed By: Kevin Berman, MD, PhD, Atlanta Center for Dermatologic Disease, Atlanta, GA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.