Benign Growths & Cysts
Epidermal Inclusion Cysts
Epidermoid cyst; "sebaceous cyst"
Very common
No — you cannot catch it or spread it
Benign; removable, best when not inflamed
What Is It?
An epidermal inclusion cyst is a common, benign lump under the skin filled with keratin, a soft, cheese-like material. It usually has a tiny central pore and can appear on the face, neck, trunk, or back. It's harmless but can become swollen, tender, or infected if it ruptures.
Signs & Symptoms
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A smooth, round lump under the skin
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A small central pore or dark punctum
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Thick, cheesy material if it drains (often with odor)
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Usually painless unless inflamed or infected
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May become red, swollen, and tender if ruptured
Why Does It Happen?
These cysts form when surface skin cells become trapped under the skin and continue to produce keratin, which collects into a sac. They can arise on their own or after a minor injury to the skin or a follicle. They are NOT cancerous. Squeezing or trauma can cause them to rupture and become inflamed. They are NOT contagious.
Treatment Options
A quiet cyst needs no treatment. Removal is best done when the cyst is not inflamed; an infected or inflamed cyst is treated first, then removed later if desired.
OBSERVATION
Reasonable for a small, painless cyst that isn't bothersome.
COMPLETE EXCISION
Removing the whole cyst sac when it's calm gives the best cure.
INCISION & DRAINAGE
Drains an acutely inflamed or infected cyst for relief.
ANTIBIOTICS
Used when there's surrounding infection.
Tips for Managing It at Home
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Don't squeeze or pop it — this can cause rupture and infection
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Warm compresses may soothe a mildly inflamed cyst
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Know that draining alone often leads to recurrence
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Plan removal when the cyst is not inflamed for the best result
When to Call Your Provider
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The lump becomes red, swollen, painful, or warm
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Rapid growth or a lump that feels firm and fixed
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Drainage of pus or a foul-smelling fluid
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You'd like it removed
Sources & further reading
The information in this handout is based on general dermatology guidance from the reputable organizations below. These links are provided for patients who wish to read more from trusted sources.
DermNet. Epidermoid Cyst. https://dermnetnz.org/topics/epidermoid-cyst
MSD/Merck Manual. Cutaneous Cysts. https://www.msdmanuals.com/professional/dermatologic-disorders/benign-skin-tumors-growths-and-vascular-lesions/cutaneous-cysts
Cleveland Clinic. Epidermoid Cysts. https://my.clevelandclinic.org/health/diseases/14165-epidermoid-cysts
This handout is for general education and does not replace advice from your own provider. Always follow your provider’s specific instructions.
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