Epidermoid Cyst
Also known as: Sebaceous Cyst (misnomer), Infundibular Cyst
Slow-growing, round, skin-colored lump filled with keratin. Benign but can become painfully infected.
What to look for
Side-by-side comparison
Normal skin
No bumps with pore
Epidermoid cyst
Round lump, central punctum
Epidermoid cysts are the most common type of skin cyst. They are slow-growing, round, firm, mobile nodules located in the dermis or subcutaneous tissue, filled with keratin (not sebum, despite the common misnomer "sebaceous cyst").
They typically have a visible central punctum (a small dark dot representing the blocked pore from which the cyst originated). They range from pea-sized to several centimeters and are most common on the face, neck, trunk, and behind the ears.
Epidermoid cysts are completely benign and do not require treatment unless they become symptomatic. However, they can become inflamed or infected, causing sudden painful swelling, redness, and sometimes rupture with discharge of foul-smelling, cheese-like keratin material.
Treatment of an inflamed cyst involves incision and drainage, sometimes with antibiotics. For definitive treatment, the entire cyst wall must be excised - otherwise the cyst will recur. Elective excision when the cyst is non-inflamed results in the lowest recurrence rate.
Quick self-check
Does this look like epidermoid cyst? Answer 2 questions.
Is it a round, firm, mobile lump with a visible central pore or dot?
Has it become red, painful, or started draining?
Risk factors
- Young to middle-aged adults (most common age group)
- Male sex (slightly more common)
- Acne history
- Minor trauma or blocked hair follicles
When to see a dermatologist
- ⚠A cyst that becomes red, painful, swollen, or warm (infection)
- ⚠A rapidly growing cyst
- ⚠Any cyst you want removed for cosmetic reasons
- ⚠Recurrence after previous drainage
Often confused with
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Full ABCDE check →Frequently asked questions
Is an epidermoid cyst the same as a sebaceous cyst?
The term 'sebaceous cyst' is a common misnomer. True sebaceous cysts (steatocystomas) are rare. Most cysts called 'sebaceous cysts' are actually epidermoid cysts filled with keratin, not sebum.
Can I squeeze it myself?
Squeezing or attempting to pop a cyst at home is not recommended. It can cause infection, push contents deeper into tissue, and lead to scarring. If a cyst bothers you, see a dermatologist for proper excision.