Sebaceous cystDefinition: A sebaceous cyst is a closed sac under the skin filled with a cheese-like or oily material.
See also:
Alternative Names: Epidermal cyst; Keratin cyst; Epidermoid cyst
Causes, incidence, and risk factors: Sebaceous cysts most often arise from swollen hair follicles. Skin trauma can also induce a cyst to form. A sac of cells is created into which a protein called keratin is secreted.
These cysts are usually found on the face, neck, and trunk. They are usually slow- growing, painless, freely movable lumps beneath the skin. Occasionally, however, a cyst will become inflamed and tender.
Symptoms: The main symptom is usually a small, non-painful lump beneath the skin.
If the lump becomes infected or inflammed, other symptoms may include:
- Skin redness
- Tender or sore skin
- Warm skin in the affected area
Grayish-white, cheesy, foul-smelling material may drain from the cyst.
Signs and tests: In most cases, your doctor can diagnose this type of cyst by simply examining your skin. Occasionally, a biopsy may be needed to rule out other conditions.
Treatment: Sebaceous cysts are not dangerous and can usually be ignored. Placing a warm moist cloth (compress) over the area may help the cyst drain and heal.
If you have a small inflamed cyst, your doctor may inject it with a steroid medicine that reduces swelling.
If the cyst becomes swollen, tender, or large, your doctor may drain it or perform surgery to remove it.
Expectations (prognosis): Large, painful cysts may interfere with day-to-day life.
Complications: These cysts may occasionally become infected and form painful abscesses .
The cysts may return after they are surgically removed.
Calling your health care provider: Call your health care provider if you notice any new growths on your body. Although cysts are not dangerous, your doctor should examine you for signs of skin cancer.
References: Habif TP, ed. Clinical Dermatology. 5th ed. Philadelphia, Pa: Mosby Elsevier; 2009.
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