A sebaceous cyst is a common, usually harmless lump that forms under the skin when a hair follicle or oil gland gets blocked.
Today, doctors more accurately call most of these epidermoid cysts (even though “sebaceous cyst” is still widely used).
What is a sebaceous cyst?
Epidermoid cyst
It is:
- A slow-growing lump under the skin
- Filled with keratin (thick, cheesy material)
- Usually painless unless infected
- Often found on the face, neck, back, or scalp
Main causes
1. Blocked hair follicle
The most common cause:
- Skin cells get trapped instead of shedding normally
- A sac forms under the skin
2. Skin trauma or irritation
- Cuts
- Acne
- Scratching or friction
These can trigger blockage of skin cells.
3. Hormonal changes
- Can increase oil production
- May indirectly contribute to blocked pores
4. Genetic factors
Some people are simply more prone to developing cysts.
5. Acne-related conditions
People with oily skin or acne are more likely to develop them.
Symptoms
A sebaceous cyst usually looks like:
- Round, smooth lump under the skin
- Movable when touched
- Slow-growing
- May have a small central black dot (blocked pore)
If infected:
- Redness
- Pain
- Swelling
- Pus or foul-smelling discharge
Home care (safe management)
⚠️ Important: You cannot permanently remove a cyst at home. But you can manage symptoms.
1. Warm compress
- Apply warm cloth for 10–15 minutes
- Helps reduce swelling and may encourage drainage
2. Keep it clean
- Wash gently with mild soap and water
- Avoid harsh scrubbing
3. Do NOT squeeze or pop it
This can cause:
- Infection
- Scarring
- Cyst recurrence
- Spread of inflammation
4. Pain relief (if needed)
- Over-the-counter painkillers may help if inflamed
Medical treatment options
If the cyst is large, painful, or recurring:
1. Drainage
- Doctor makes a small cut and drains fluid
- Temporary relief (cyst may come back)
2. Surgical removal
- Entire cyst wall is removed
- Most effective permanent solution
3. Antibiotics
Only used if there is infection—not for all cysts.
When to see a doctor
Seek medical help if:
- Rapid growth
- Pain or redness
- Signs of infection
- Location causes discomfort (face, scalp, genitals)
- It keeps coming back
Bottom line
A sebaceous (epidermoid) cyst is a benign skin lump caused by blocked skin cells under the skin. It is usually harmless and slow-growing. Home remedies like warm compresses can help with discomfort, but they do not remove the cyst permanently. If it becomes painful, infected, or persistent, medical removal is the best option.
If you want, I can also show you how to tell the difference between a cyst, a boil, and a lipoma—they often get confused.
