Why Is There a Painful Bump on My Buttcheek?

A painful bump on your buttcheek is most often a skin infection, specifically a boil or abscess caused by bacteria entering a hair follicle or a small break in the skin. The buttocks are warm, prone to friction, and spend a lot of time pressed against surfaces, making them a hospitable environment for infection and inflammation. But “painful bump” is a broad description, and the actual cause ranges from something that will resolve on its own in a few days to something that warrants a same-week trip to a doctor.

Boils and Skin Abscesses

The single most common explanation is a boil, also called a furuncle. A boil starts when bacteria infect the root of a hair follicle or a blocked oil gland, causing a red, swollen, tender lump that fills with pus over several days. The organism behind most of these is Staphylococcus aureus, the leading cause of skin and soft tissue infections in the United States.¹ When community-acquired strains of staph cause skin infections, they tend to show up as single abscesses, and the perineal and buttock area is one of the most frequently affected sites.²

A small boil will often come to a head and drain on its own within a week or two. Warm compresses several times a day can speed this along by drawing the pus closer to the surface. You should not squeeze or lance the bump yourself, because pushing bacteria deeper into surrounding tissue can turn a simple boil into a larger abscess or trigger cellulitis, a spreading skin infection that requires antibiotics. If the bump grows larger than roughly the size of a golf ball, if it sits deep in the tissue without coming to a head, or if you develop a fever, a doctor will likely need to drain it with a sterile incision and may prescribe antibiotics.

Epidermoid Cysts

If the bump has been there for weeks or months and only recently became painful, you may be dealing with an epidermoid cyst. These are sac-like structures that form in the skin and gradually fill with a thick, cheese-like material made of keratin, the same protein in your hair and nails. They are usually painless and slow-growing, but they become a problem if they rupture or get infected. When the cyst wall breaks, its contents leak into the surrounding tissue and trigger an intense inflammatory reaction, sometimes forming a hard, painful lump that looks and feels a lot like an abscess.³

The key difference between an infected cyst and a boil is that cysts tend to recur. If a doctor drains the infection but leaves the cyst wall behind, the sac will refill and eventually flare up again. Complete surgical removal of the cyst, typically done once the acute infection has cooled down, is the definitive fix. If you have had the same painful bump in the same spot more than once, an epidermoid cyst is a strong possibility.

Pilonidal Cysts

When the bump sits at or near the crease between your buttocks rather than on the fleshy part of the cheek, a pilonidal cyst is a common suspect. These form when loose hairs get pushed beneath the skin of the natal cleft, sparking a chronic inflammatory reaction. There is strong consensus that pilonidal disease is acquired rather than something you are born with, with hair being the agent that drives the condition.⁴ People with thick or coarse body hair, those who sit for long stretches, and individuals who experience a lot of friction in that area are more prone.

A pilonidal cyst can simmer quietly for a long time and then flare into an acute abscess, producing sudden pain, swelling, and sometimes drainage of foul-smelling fluid or blood. Initial treatment is drainage and antibiotics, but many people with pilonidal disease need surgical excision of the sinus tract to prevent repeated flares.

Hidradenitis Suppurativa

If you keep getting painful bumps in the buttock region and they seem to come in clusters or leave scars and tunneling tracks under the skin, a chronic condition called hidradenitis suppurativa (HS) may be involved. HS starts when hair follicles become blocked, leading to deep inflammation, secondary infection, and eventual destruction of the surrounding tissue. In men, the peri-anal and buttock areas are among the most commonly affected sites.⁵

HS is chronically underdiagnosed, partly because early-stage disease looks just like ordinary boils. The average patient sees multiple doctors over several years before getting a correct diagnosis. Two clues that set HS apart from simple boils: the bumps tend to recur in the same general zones (groin, buttocks, underarms), and over time they leave rope-like scars or draining sinus tracts. Treatment ranges from antibiotics and anti-inflammatory medications in mild cases to biologic drugs or surgery in severe ones. If your “boils” keep coming back in the same areas, bring up HS with your doctor specifically, because a general practitioner may not think of it unprompted.

Ischiogluteal Bursitis

Not all painful bumps on the buttock involve the skin. If the lump feels deep, sits right over the bony part you sit on, and hurts most when you are seated, the problem may be an inflamed bursa. The ischial tuberosity, the “sit bone” at the base of your pelvis, is cushioned by a fluid-filled sac called the ischiogluteal bursa, and repeated pressure or friction can cause that sac to swell and become painful. Patients typically describe a gradually increasing, painful mass in the buttock.⁶

This condition is classically associated with people who sit for long hours, especially on hard surfaces or while exposed to vibration, such as long-distance truck drivers, heavy-equipment operators, and industrial sewing-machine workers. Athletes who fall directly onto their backside can develop an acute version from a single shearing force on the sit bone, which can become chronic and disabling enough to keep them out of their sport.⁷ Treatment usually involves rest, anti-inflammatory medications, and cushioning modifications. A corticosteroid injection may be offered for stubborn cases.

Bumps After an Injury or a Fall

If the painful lump appeared shortly after you fell, took a hard hit, or even sat down too hard on a sharp surface, post-traumatic fat necrosis is a possibility. The buttock contains a thick layer of subcutaneous fat, and blunt force can damage that fat tissue, causing it to die and harden into a firm, tender mass. All patients in one case series recalled blunt trauma to the posterior pelvis just before symptoms started, including falls down stairs and falls from a bed.⁸ The resulting mass can mimic a tumor on imaging and sometimes causes chronic pain. Most cases settle on their own, but surgical excision is occasionally needed if the lump persists or causes ongoing discomfort.

Injection Site Complications

The buttock is one of the most common sites for intramuscular injections, and a painful lump following a shot there is not always just routine soreness. If injection technique is off, a needle can injure a blood vessel, and bleeding from the superior gluteal artery can form a deep hematoma. Left untreated, that hematoma can become a deep abscess and progress toward a pre-septic state.⁹ A lump that appears at an injection site and keeps growing, becomes increasingly warm and red, or is accompanied by fever should be evaluated promptly rather than dismissed as a normal reaction to the shot.

Cyclist’s Nodule and Other Activity-Specific Lumps

Spending long hours on a bicycle or horseback saddle can produce a distinctive condition called perineal nodular induration, better known as cyclist’s nodule. This benign growth forms in response to repetitive pressure and microtrauma from the saddle, and it typically appears in the perineum or near the sit bones on the lower buttock.¹⁰ Because it presents as a firm, sometimes painful mass in a soft tissue area, it can initially raise concern for a more serious tumor. Imaging and biopsy usually clarify the diagnosis, and treatment involves addressing the saddle fit, taking breaks from riding, or, in persistent cases, surgical removal.

Herpes Zoster in the Sacral Area

A painful bump that turns out to be a cluster of small blisters, usually on just one side of the buttock, could be shingles. Herpes zoster can affect the sacral nerves that supply the buttock skin, producing burning pain and grouped vesicles along a nerve pathway, typically a band or strip on one side of the body.¹¹ The pain often precedes the visible rash by a day or two, which means you may feel a localized burning or stabbing sensation under the skin before any lesion appears. Antiviral medication works best when started within 72 hours of the rash, so prompt evaluation matters.

Deep Abscesses From the Anorectal Region

Occasionally, what feels like a painful bump on the buttcheek is actually the outward manifestation of an infection that originated deeper inside, near the anus. Anal fistulas and perianal abscesses can track through tissue planes and present as a swollen, painful lump on the surface of the buttock, sometimes far from the anus itself. Case reports describe infections that spread from the anal gland through the intersphincteric space and ischiorectal fossae all the way into the gluteal compartment.¹² Anal fistulas can extend beyond the perianal space into the subcutaneous tissue of the buttocks, leading to severe infection.¹³

A clue that points toward this deeper origin is the presence of drainage (especially foul-smelling), a history of perianal symptoms, or a bump that keeps recurring despite surface-level treatment. Inflammatory bowel disease, particularly Crohn’s disease, increases the risk of perianal fistulas and can even cause isolated skin lesions on the buttocks as a rare complication called metastatic cutaneous Crohn’s disease.¹⁴ This is extremely uncommon, but if you have known Crohn’s and develop persistent buttock nodules, your gastroenterologist should know about them.

Nerve Sheath Tumors

Among the rarer possibilities, a schwannoma, a benign tumor of the nerve sheath, can grow along the sciatic nerve or its branches in the deep gluteal area and produce a gradually increasing painful lump. One reported case involved a woman with a year of progressive buttock discomfort traced to a roughly 3-centimeter cystic mass attached to the sciatic nerve; hip arthroscopy and microsurgery removed the growth, and her symptoms resolved completely.¹⁵ Larger schwannomas can grow to substantial sizes before diagnosis. In another case, a patient presented with a large buttock mass that biopsy confirmed as a schwannoma of the sciatic nerve.¹⁶

If a deep buttock lump comes with shooting pain down the leg or unusual tingling and numbness, the involvement of a major nerve is more likely, and imaging with MRI becomes important to distinguish a nerve tumor from a cyst or other soft tissue mass.

Soft Tissue Sarcomas

This is the possibility nobody wants to hear about, but it is worth mentioning because early recognition matters. Soft tissue sarcomas can arise in the buttock, and a systematic review of buttock sarcomas found that the most common types were liposarcoma, rhabdomyosarcoma, and undifferentiated pleomorphic sarcoma.¹⁷ These tumors are rare, but their deep location in the buttock means they can grow for months before anyone pays attention. In one study of primary high-grade buttock sarcomas, the average time from symptom onset to diagnosis was about four and a half months.¹⁸

Red flags for a sarcoma include a mass that is deep, firm, painless or only mildly painful, steadily growing over weeks, and larger than about five centimeters. Most painful buttock bumps are not sarcomas, but any lump that keeps getting bigger without signs of infection deserves imaging rather than a wait-and-see approach.

When to Seek Urgent Care

Most painful bumps on the buttcheek are self-limiting or easily treatable with drainage and antibiotics. But certain signs suggest something more dangerous is happening. Necrotizing fasciitis, sometimes called flesh-eating infection, can start in the buttock or perineal area. It spreads quickly and can be fatal without emergency surgical treatment. Standard laboratory scoring tools miss a meaningful number of cases, with one emergency-department study finding that a commonly used screening score had an overall sensitivity of only about 77%, meaning roughly one in four cases scored below the threshold that would raise alarm.¹⁹ That means clinical suspicion matters more than lab numbers alone.

Go to an emergency department if you experience any of the following alongside a buttock bump:

• Rapidly spreading redness: skin discoloration that expands visibly over hours, not days.
• Severe pain out of proportion: pain that seems far worse than the visible skin changes would suggest, or pain that suddenly worsens.
• Crepitus: a crackling or popping sensation under the skin, which can indicate gas-producing bacteria in the tissue.
• High fever with chills: systemic signs of infection, especially if accompanied by rapid heart rate or confusion.
• Skin blistering or darkening: dusky, gray, or blackened skin overlying the area.

Outside of emergencies, a good rule of thumb is to see a doctor if the bump has not improved within two weeks of home care, if it is deeper than the skin surface and you cannot feel a clear boundary, if it keeps coming back in the same area, or if you notice drainage from a spot near the anus that you did not previously connect to the buttock lump. Most of these conditions are straightforward to diagnose with a physical exam and, when needed, ultrasound or MRI, and the earlier you address the cause, the simpler the treatment tends to be.