Sebaceous Cyst

What is sebaceous cyst?

A sebaceous cyst is a common, usually harmless lump that forms just under the skin. It is a closed sac, or pocket, filled with a thick, yellowish or white material made mostly of keratin, the protein that skin and hair are made of. The lump is typically round, moves slightly when you press on it, and grows slowly over months or years. In medical coding, this condition is listed under ICD-10 code L72.3.

The term “sebaceous cyst” is widely used by patients and even by many clinicians, but it is worth knowing that most of these lumps are technically epidermoid cysts (arising from the top layer of skin) or pilar cysts (arising from the lining of a hair follicle, most often on the scalp). True cysts of the sebaceous glands, which are the small glands that produce skin oil, are less common. Because the everyday name is so familiar, this article uses “sebaceous cyst” to cover the group of related lumps that doctors manage in a similar way.

Understanding what is sebaceous cyst in practical terms helps reduce worry: it is a benign (non-cancerous) skin lump in the vast majority of cases. These cysts can appear at almost any age but are most often noticed in adults between young adulthood and middle age. They occur in both men and women, and they can develop almost anywhere on the body. Common locations include the face, neck, scalp, back, chest, behind the ears, and the genital area. They rarely appear on the palms of the hands or soles of the feet.

Most sebaceous cysts cause no health problems and many never need treatment. However, they can become inflamed, infected, or bothersome because of their size or location, and in those situations medical care is helpful. At hospital groups such as Acibadem, sebaceous cysts are usually evaluated and managed by the dermatology department, with general surgery or plastic surgery involved when a cyst needs to be removed.

Symptoms of sebaceous cyst

Many people discover a sebaceous cyst by chance, while washing, shaving, or dressing, because in its quiet state it often causes no discomfort at all. Recognizing typical sebaceous cyst symptoms can help you describe the lump accurately to your doctor.

Common features of an uncomplicated sebaceous cyst include:

• A round, dome-shaped lump under the skin, usually ranging from a few millimeters to several centimeters across.
• Slow growth over months or years, or a stable size for a long time.
• A smooth surface that moves slightly when pushed, because the sac sits under the skin rather than being fixed to deeper tissue.
• A small central dark dot or opening, called a punctum, visible on the skin over some cysts. This is the blocked opening of the original hair follicle or pore.
• Little or no pain when the cyst is not inflamed.
• Occasional discharge of thick, cheese-like material with an unpleasant odor if the cyst leaks or is squeezed (squeezing is not recommended, as explained below).

Symptoms change noticeably if a cyst becomes inflamed or infected. This can happen if the sac ruptures under the skin, releasing its contents into the surrounding tissue, or if bacteria enter the cyst. An inflamed or infected sebaceous cyst may show:

• Redness of the overlying skin (or a darker, purplish tone on deeper skin colors).
• Warmth and tenderness, so the lump hurts when touched or when clothing rubs against it.
• Rapid swelling, sometimes over a few days.
• Pus or foul-smelling fluid draining from the cyst.
• Fever or feeling unwell in more significant infections, which is a sign that prompt medical attention is needed.

Symptoms can also vary by type and location. Pilar cysts on the scalp often feel firmer and may be noticed while combing hair; they frequently occur in multiples and can run in families. Cysts on the face or neck may be mainly a cosmetic concern. Cysts in areas of friction, such as the back, the waistline, or the genital region, are more likely to become irritated. A cyst that has been present quietly for years and then suddenly becomes painful has usually become inflamed or infected rather than turned into anything more serious, but any rapid change deserves a medical review.

Causes and risk factors

Sebaceous cyst causes come down to a simple mechanical problem: skin cells or gland openings become trapped or blocked, and material that would normally be shed from the skin surface collects under it instead. Over time, this trapped material forms the sac and its contents.

Situations and factors that can lead to a cyst forming include:

• Blocked hair follicles or pores. A follicle is the tiny tunnel in the skin from which a hair grows. If its opening becomes plugged, cells and keratin can build up beneath it.
• Skin injury. A cut, scrape, surgical wound, or piercing can push surface skin cells deeper into the skin, where they continue to multiply and form a cyst wall. This may happen weeks or months after the injury.
• Acne and oily skin. People with a history of acne, a condition in which pores frequently become blocked, appear more prone to developing these cysts.
• Damaged or swollen hair follicles, for example from repeated shaving irritation or inflammation.
• Genetic factors. Pilar cysts of the scalp often run in families. In addition, certain rare inherited conditions, such as Gardner syndrome (a genetic disorder that also affects the bowel) and steatocystoma multiplex (a condition causing many small oil-gland cysts), are associated with multiple cysts. These conditions are uncommon, and having one or two ordinary cysts does not suggest you have them.

Risk factors that make sebaceous cysts more likely include being past puberty (they are rare in young children), a personal or family history of cysts, a history of acne, and previous skin trauma in the affected area. Importantly, sebaceous cysts are not caused by poor hygiene, and they are not contagious — you cannot catch one from another person or spread it on your own body by touch.

Diagnosis

Sebaceous cyst diagnosis is usually straightforward and, in many cases, requires no tests at all. A doctor — often a family physician or a dermatologist, which is a skin specialist — typically identifies the cyst by looking at it and gently feeling it. The classic combination of a slow-growing, movable, dome-shaped lump under the skin, sometimes with a visible central punctum, is often enough to make a confident clinical diagnosis.

Your doctor will usually ask questions such as how long the lump has been present, whether it has changed in size, whether it has ever been painful, red, or draining, and whether you have had similar lumps before or any previous injury to the area.

Additional tests are reserved for situations where something about the lump is unusual. These may include:

• Ultrasound. A painless scan using sound waves that can show whether the lump is a fluid- or keratin-filled sac (consistent with a cyst) or a solid growth, and how deep it extends. Ultrasound is often used when a lump sits in a sensitive location or does not feel typical.
• CT or MRI scans. These detailed imaging studies are rarely needed but may be used for very large lumps, lumps in unusual locations (for example near the spine or on the midline of the head in a child), or when the doctor needs to plan surgery around important structures.
• Biopsy or histopathology. A biopsy means taking a small sample of tissue for examination under a microscope. More commonly, when a cyst is surgically removed, the entire sac is sent to a laboratory for routine examination. This confirms the diagnosis and rules out rare look-alike conditions.

Part of the diagnostic process is distinguishing a sebaceous cyst from other lumps, such as a lipoma (a soft, benign fatty lump that sits deeper and has no punctum), an abscess (a collection of pus from infection), an enlarged lymph node, or, rarely, a skin tumor. A lump that is fixed to deep tissue, grows quickly, feels hard and irregular, or ulcerates through the skin does not fit the usual picture of a cyst and will prompt further investigation.

Treatment options

Sebaceous cyst treatment depends on whether the cyst is causing problems. There is no cream, tablet, or home remedy that reliably makes the cyst sac disappear, because the sac wall remains under the skin even if the contents drain. Treatment choices generally fall into the following categories.

Watchful waiting

If a cyst is small, painless, and not bothering you, your doctor may recommend simply leaving it alone and keeping an eye on it. Many cysts remain stable for years, and some occasionally shrink on their own. Watchful waiting means monitoring the lump for changes in size, tenderness, or the overlying skin and returning for review if anything changes.

Care for an inflamed cyst

When a cyst becomes inflamed but is not clearly infected, doctors often suggest warm compresses — a clean cloth soaked in warm water held against the area several times a day — to ease discomfort and encourage the inflammation to settle. In some cases, a doctor may inject a small amount of corticosteroid (an anti-inflammatory medication) into the area to reduce swelling. It is important not to squeeze or pierce the cyst yourself; doing so can push the contents deeper, worsen inflammation, introduce infection, and cause scarring, and the cyst usually refills anyway because the sac is still there.

Treatment of an infected cyst

If the cyst is infected, your doctor may prescribe antibiotics, which are medications that fight bacterial infection. If pus has collected, the doctor may perform an incision and drainage: a small cut is made under local anesthesia (numbing medication injected into the skin) to release the pus. This relieves pain quickly, but it is not a cure, because the sac wall is usually left in place and the cyst can come back later. Definitive removal is generally postponed until the infection and inflammation have settled, since surgery on inflamed tissue is more difficult and more likely to leave the sac incomplete.

Surgical removal

The only treatment that can permanently remove a sebaceous cyst is surgery to take out the entire sac. This is usually a minor procedure done under local anesthesia in a clinic or outpatient operating room, meaning you go home the same day. Common techniques include:

• Conventional excision. The surgeon makes a small cut over the cyst, removes the sac whole, and closes the wound with stitches. Removing the sac intact gives the lowest chance of recurrence.
• Minimal excision. A smaller opening is made, the contents are expressed, and the sac wall is then drawn out through the small opening. This leaves a smaller scar but may carry a somewhat higher chance of the cyst returning if part of the wall stays behind.
• Punch excision. A small round instrument removes a core of skin including the punctum, allowing the sac to be removed through the opening.

Recovery from cyst removal is usually quick. The area may be mildly sore for a few days, stitches (if not dissolvable) are typically removed after about one to two weeks depending on the site, and most people return to normal activities promptly, avoiding heavy strain on the wound while it heals. All surgery leaves some scar, though surgeons place incisions to keep scarring as discreet as possible. The removed tissue is normally sent for laboratory examination as a routine safeguard. In multidisciplinary centers, including Acibadem facilities, straightforward removals are performed by dermatologists or general surgeons, while plastic surgery may be preferred for cysts on the face or other cosmetically sensitive areas.

Living with sebaceous cyst and outlook

The outlook for people with a sebaceous cyst is very good. These cysts are benign, and having one does not raise your risk of skin cancer in any meaningful way; cancerous change within a cyst is considered very rare. Many cysts never cause trouble and can safely be left alone for a lifetime.

Day to day, sensible measures include keeping the area clean, avoiding squeezing or picking at the lump, and reducing friction where possible — for example, choosing clothing that does not rub against a cyst on the back or waistline. If a cyst sits where you shave, take care to avoid nicking it, as small injuries can trigger inflammation.

If a cyst is removed with the sac intact, it does not usually come back in the same spot, although no procedure can guarantee this, and a small recurrence risk remains if any part of the wall was left behind. People who are prone to cysts may develop new ones elsewhere over time; this reflects their skin’s tendency rather than a failure of treatment. If you notice new lumps, changes in an existing lump, or repeated episodes of inflammation, a review with your doctor is reasonable. In most cases, living with a sebaceous cyst means little more than occasional self-checks and knowing which changes should prompt a medical visit.

Frequently asked questions

What is a sebaceous cyst and is it dangerous?

A sebaceous cyst is a benign sac under the skin filled with keratin, a natural skin protein. In the great majority of cases it is not dangerous. The main risks are discomfort, infection, and cosmetic concern rather than serious disease. That said, only a doctor can confirm that a lump is truly a cyst, so any new or changing lump should be checked rather than assumed to be harmless.

Can a sebaceous cyst go away on its own?

Sometimes. Small cysts may shrink or stop being noticeable, and an inflamed cyst can settle down with warm compresses and time. However, because the sac wall remains under the skin, many cysts persist indefinitely or return after draining. The only way to remove a cyst permanently is surgical removal of the entire sac.

Should I squeeze or pop a sebaceous cyst at home?

No. Squeezing or piercing a cyst can push its contents into the surrounding tissue, causing painful inflammation, and can introduce bacteria, leading to infection. It also often causes scarring, and the cyst usually refills because the sac is still in place. If a cyst is bothering you, it is safer to have a doctor assess it and, if appropriate, remove or drain it under sterile conditions.

How do doctors diagnose a sebaceous cyst?

Sebaceous cyst diagnosis is usually made by physical examination alone, based on the lump’s typical look and feel. If anything is unusual — rapid growth, a fixed or hard lump, or an atypical location — the doctor may order an ultrasound scan or, rarely, other imaging. When a cyst is removed, the tissue is generally examined in a laboratory to confirm the diagnosis.

What is the best treatment for a sebaceous cyst?

There is no single best sebaceous cyst treatment for everyone. A quiet, small cyst often needs no treatment at all. An inflamed cyst may respond to warm compresses or a steroid injection, and an infected cyst may need antibiotics or drainage. If a cyst is painful, recurrent, enlarging, or cosmetically bothersome, surgical removal of the whole sac is the standard definitive option. Your doctor can help you weigh these choices based on the cyst’s size, location, and history.

What is recovery like after cyst removal?

Removal is usually a short outpatient procedure under local anesthesia. Afterward, mild soreness for a few days is common, and you will be advised to keep the wound clean and dry initially and to avoid heavy strain on the area while it heals. Non-dissolvable stitches are typically removed after about one to two weeks, depending on the body site. Some scarring is expected, and it generally fades over months.

Can a sebaceous cyst come back after removal?

If the entire sac is removed intact, recurrence at the same site is uncommon, though it cannot be entirely ruled out. If only the contents were drained, or a fragment of the wall was left behind, the cyst can refill over time. People who are prone to cysts may also develop new, separate cysts elsewhere on the body, which is not a recurrence of the treated one.

When to see a doctor

Most sebaceous cysts are not urgent, but a medical review is sensible for any new lump so that the diagnosis can be confirmed. See a doctor promptly if any of the following occurs:

• The lump becomes red, warm, swollen, or increasingly painful, which may indicate infection.
• Pus or foul-smelling fluid drains from the cyst.
• You develop a fever or feel generally unwell alongside a painful cyst.
• Spreading redness or streaks extend from the lump into the surrounding skin, a possible sign of a spreading skin infection.
• The lump grows quickly, changes character, feels hard or fixed to deeper tissue, or the skin over it breaks down.
• The cyst returns repeatedly after drainage or previous treatment.
• The cyst is in a sensitive location — such as the face, genital area, or near the eye — where inflammation or scarring could cause particular problems.

If you have diabetes, a weakened immune system, or take medications that suppress immunity, seek medical advice earlier for any signs of infection, as infections can progress more quickly in these situations. A doctor can confirm whether the lump is a sebaceous cyst, treat any infection, and discuss whether removal is appropriate for you.