Sebaceous Cyst

What a sebaceous cyst is

Sebaceous glands sit beside hair follicles and make sebum, the skin's oil. The term "sebaceous cyst" has been used for decades for any small skin cyst, but under the microscope most turn out to be one of two types:

The old word wen refers to a cyst on the scalp. Because the treatment is the same, many doctors still say sebaceous cyst for all of them.

Symptoms

• A smooth, dome-shaped lump from a few millimeters to several centimeters
• Firm or rubbery and moves slightly when pushed
• Skin-colored, white or yellowish
• Often a tiny dark opening on top (a punctum), which is the blocked pore
• Usually painless and very slow growing
• May leak thick, white, smelly material if squeezed

Inflamed or infected sebaceous cyst

A cyst wall can leak or rupture, often after squeezing. The keratin irritates the surrounding skin, causing:

• redness, warmth and swelling within a day or two
• throbbing pain and tenderness
• pus or foul discharge

Most "infected" cysts are actually inflamed from rupture rather than bacterial infection, but true infection with an abscess can occur.

Sebaceous cyst on the upper eyelid: symptoms

Small cysts on the eyelid are common. Typical features:

• A painless, smooth, pale or yellow bump on the eyelid skin or margin
• No redness or pain unless it becomes inflamed
• Slow growth over weeks to months
• A larger one can press on the eye and blur vision slightly, or feel heavy

Several other eyelid lumps look similar:

A persistent or recurrent eyelid lump in an older adult should be checked by an eye doctor, because rare cancers such as sebaceous gland carcinoma can mimic a chalazion. See eyelid cysts for more.

Causes and risk factors

A cyst forms when skin cells that should shed from the surface get trapped beneath it and keep producing keratin into a closed sac. Triggers include:

• a blocked or damaged hair follicle
• acne and sun-damaged skin
• injuries, piercings or surgical scars that bury skin cells
• family history (especially pilar cysts)
• rare genetic conditions such as Gardner syndrome, when many cysts appear in childhood

They are most common in adults aged 20 to 60 and slightly more common in men.

How it is diagnosed

A doctor can usually tell from looking at and feeling the lump. Ultrasound may help if it is deep or unusual. Removed cysts are sometimes sent for microscopic examination, particularly from the eyelid or if they look atypical.

Sebaceous cyst vs lipoma

Treatment

Leaving it alone

Small cysts that cause no problems can safely be left. Do not squeeze them: this forces keratin into the skin and is the most common reason they become inflamed.

Treating an inflamed cyst

• Warm compresses for 10 to 15 minutes several times a day
• An injection of steroid into the cyst to settle inflammation quickly
• Cutting and draining (incision and drainage) for a large, painful, fluctuant cyst or abscess. This relieves pain, but the cyst often returns because the wall is left behind
• Antibiotics only if there is spreading infection (cellulitis)

Permanent removal

Surgical excision under local anesthetic removes the whole cyst including its wall. It is best done when the cyst is calm, usually 4 to 6 weeks after any inflammation has settled. Options are a small elliptical excision or a minimal-incision technique through a small punch. Recurrence is uncommon after complete removal. Eyelid cysts are removed by an eye surgeon to protect the lid margin and lashes.

Outlook

Sebaceous-type cysts are benign. Cancer arising in an epidermoid cyst is extremely rare. They may stay the same size for years, slowly grow or occasionally disappear after rupturing, but usually refill if the wall remains.

Frequently asked questions

What are the symptoms of a sebaceous cyst on the upper eyelid?

It is usually a small, smooth, painless bump on or under the eyelid skin that grows slowly. It may be white or yellow and can make the lid feel heavy. Redness, pain or swelling suggests inflammation, and a lump that keeps returning should be checked by an eye doctor.

Can I pop a sebaceous cyst?

It is best not to. Squeezing rarely empties the sac and often ruptures it under the skin, causing painful inflammation and scarring, and the cyst usually refills. A doctor can drain it if needed or remove it completely.

How can I tell if a sebaceous cyst is infected?

An infected or inflamed cyst becomes red, warm, swollen and painful, and may discharge pus. Fever or spreading redness means you should see a doctor promptly. Warm compresses help mild inflammation in the meantime.

Will a sebaceous cyst go away on its own?

Occasionally a cyst shrinks after draining spontaneously, but most persist or come back because the sac remains. They are harmless, so many people leave them. Surgical removal of the whole wall is the only reliable cure.

Is a sebaceous cyst cancerous?

Almost never. These cysts are benign. A lump that grows quickly, is hard and fixed, bleeds or ulcerates is not typical of a cyst and should be examined. On the eyelid, a persistent lump in an older adult deserves review to rule out a rare gland cancer.