What is this lump on one side of my buttocks? Causes, Symptoms, and Treatment

September 27, 2025 •

4 min read

According to the American Academy of Family Physicians, lipomas—a common cause of lumps—are benign fatty tumors that affect approximately 1 in 1,000 people. Encountering a lump on one side of your buttocks can be alarming, but most are benign. This authoritative guide provides information on common causes, helping you understand your symptoms and decide when to see a doctor.

Quick Summary

A lump on one side of the buttocks can stem from various sources, including a harmless fatty growth (lipoma), an infected hair follicle (folliculitis or abscess), or a fluid-filled sac (cyst). The lump's texture, tenderness, and associated symptoms are key to distinguishing the possible cause.

Key Points

Lipomas vs. Abscesses: Lipomas are soft, painless fatty lumps that move easily, while abscesses are painful, red, and swollen pockets of infection that develop rapidly.
Pilonidal Cysts Can Move: Though they start in the buttock crease, an infected pilonidal cyst can present as an abscess on one side, sometimes with draining pus or a foul smell.
Hygiene and Friction are Key: Folliculitis, or "butt acne," is a common cause of small bumps, often resulting from sweat and friction from tight clothing or prolonged sitting.
Rapid Growth Is a Red Flag: A lump that grows quickly, is very painful, or accompanied by fever should be evaluated by a doctor to rule out an active infection.
Do Not Self-Treat: Attempting to drain a deep-seated lump at home can lead to a more severe infection or scarring; professional medical care is often necessary for abscesses and recurring cysts.
Diagnosis Guides Treatment: A doctor can diagnose the lump based on physical examination and may use imaging or a biopsy if needed, leading to targeted treatment from observation to surgery.

Common Causes of a Buttock Lump

Finding a lump on your body, particularly in an area like the buttocks, can be unsettling. While your first thought might be a serious condition, most lumps in this region are benign and can be managed effectively. Understanding the key characteristics of different types of lumps is the first step toward finding relief.

Lipoma

A lipoma is a benign, slow-growing tumor made of fatty tissue. It is one of the most common causes of soft-tissue lumps and typically presents with the following characteristics:

Location: Can occur anywhere on the body where fat is present, including the buttocks.
Texture: Soft, doughy, or rubbery to the touch.
Movability: Moves easily under the skin with slight finger pressure.
Pain: Generally painless, unless it grows large enough to press on nearby nerves or blood vessels.
Growth: Grows very slowly over months or years.

Skin Abscess or Boil

A skin abscess is a painful, pus-filled pocket of infection under the skin, often caused by bacteria like Staphylococcus aureus entering a hair follicle or minor skin wound. A boil is a type of abscess specifically localized to an infected hair follicle. Characteristics of an abscess include:

Symptoms: Pain, swelling, and redness around the lump.
Appearance: The lump feels hard at first but can soften and develop a pus-filled head as the infection progresses.
Progression: Can develop and grow rapidly.
Other signs: May leak pus or blood and be accompanied by fever if the infection spreads.

Pilonidal Cyst

While pilonidal cysts most commonly form in the midline buttock crease, they can sometimes present with a sinus tract or abscess that moves to one side. A pilonidal cyst is a small sac that forms at the top of the buttock crease, often containing hair and skin debris. If it becomes infected, it can lead to a painful abscess. Key signs include:

Initial Signs: A small dimple or pit at the top of the buttock crease.
Infection Symptoms: When infected, it causes pain, swelling, and redness, and may drain pus.
Recurrence: They are known to recur if the underlying sinus tracts are not removed.

Folliculitis and "Butt Acne"

Often mistaken for acne, folliculitis is a condition where hair follicles become inflamed or infected. On the buttocks, this can present as small, red, pimple-like bumps. Causes include friction from tight clothing, sweat, and improper hygiene. This is a common and usually harmless condition.

A Comparison of Common Buttock Lumps

To help differentiate the potential causes, the table below compares the typical characteristics of the most common types of buttock lumps.


Feature	Lipoma	Abscess / Boil	Pilonidal Cyst (Infected)	Folliculitis
Texture	Soft, doughy	Hard, then soft with pus	Firm, then soft with pus	Small, pimple-like bumps
Pain	Usually painless	Painful, tender	Painful, especially when sitting	Can be itchy or mildly tender
Movability	Easily movable	Fixed or difficult to move	Fixed to deeper tissue	N/A (small bumps)
Speed of Growth	Very slow (months/years)	Fast (days/weeks)	Can develop quickly	Can appear suddenly
Associated Symptoms	None	Redness, swelling, fever	Drainage, foul odor, fever	Redness, irritation

When to See a Healthcare Provider

While many buttock lumps are not serious, it is important to know when to seek medical attention to rule out more complex issues or manage a painful infection. You should see a doctor if you experience any of the following:

The lump is painful, warm, or red, and the pain is worsening.
The lump is growing rapidly.
You develop a fever or feel unwell.
The lump drains pus or blood.
The lump is hard and fixed in place.
You have changes in bowel movements or persistent anal bleeding.

Diagnosis and Treatment

Your doctor will likely perform a physical examination to feel the lump's size, consistency, and tenderness. For some cases, further diagnostic tools may be used:

Biopsy: A small tissue sample is taken to be examined in a lab, particularly if a malignancy is suspected.
Ultrasound: This imaging can help determine if the lump is solid (like a lipoma) or fluid-filled (like a cyst or abscess).

Treatment depends on the diagnosis:

Lipomas: Often, no treatment is necessary. If it's large, painful, or for cosmetic reasons, it can be surgically removed.
Abscesses: Require drainage to release the pus, often a simple in-office procedure. Antibiotics may also be prescribed.
Pilonidal Cysts: Initial treatment involves draining an infected cyst. For recurring issues, surgery to remove the sinus tract is often required.
Folliculitis: Improved hygiene, topical treatments, and avoiding friction can help.

Prevention Tips

For many common skin lumps, simple preventative measures can reduce the risk of recurrence:

Maintain good hygiene: Keep the area clean and dry, especially after sweating or exercise.
Exfoliate regularly: Gentle exfoliation can prevent hair follicles from becoming clogged.
Wear loose-fitting, breathable clothing: This reduces friction and sweat buildup, especially when sitting for long periods.
Manage body hair: If you are prone to pilonidal cysts or folliculitis, hair removal may help.

Conclusion

While a lump on one side of the buttocks can indicate various conditions, most are non-cancerous and treatable. The key to determining the cause lies in observing its characteristics and any associated symptoms. Paying attention to factors like pain, speed of growth, and texture is crucial. If the lump causes significant pain, grows rapidly, or shows signs of infection like fever or pus, consulting a healthcare professional is essential for a proper diagnosis and treatment plan. Never attempt to pop or drain a deep-seated lump at home, as this can worsen the infection. For reliable, authoritative health information, consider visiting the Cleveland Clinic website.

Frequently Asked Questions

A lipoma on the buttocks typically feels soft, doughy, or rubbery to the touch. It is often movable, meaning it can be gently shifted under the skin, and is generally not painful.

While most buttock lumps are benign, a hard, immovable, or rapidly growing lump should be evaluated by a doctor to rule out more serious conditions. A biopsy may be performed to confirm a diagnosis.

An abscess or boil is a deep, painful infection, often with significant swelling, redness, and pus. A pimple (folliculitis) is generally smaller, more superficial, and less painful, though it can become inflamed.

It depends on the cause. Small folliculitis bumps may clear up with improved hygiene. A pilonidal cyst might drain on its own but often recurs. Abscesses and larger cysts usually require medical drainage and intervention.

You should see a doctor if the lump is painful, rapidly growing, red, warm, or accompanied by fever. Any drainage of pus or blood is also a reason to seek medical attention.

Yes. Although pilonidal cysts start in the midline crease, an infection can lead to an abscess and drainage tract that extends out to one side of the buttocks.

To prevent many common skin lumps, maintain good hygiene, wear loose-fitting and breathable clothing, and avoid prolonged sitting. Managing body hair in the area can also help, especially for pilonidal cysts.

Treatment varies. Lipomas often need no treatment. Abscesses require medical drainage. Recurring pilonidal cysts may need surgical removal. Folliculitis can be managed with topical treatments and lifestyle changes.