A lesion on the buttock is most often a bacterial infection such as a boil or an inflamed hair follicle, but the buttocks are a surprisingly diverse landscape for skin problems. The area’s warmth, moisture, friction, and proximity to bacteria make it vulnerable to conditions ranging from simple pimples to chronic inflammatory disease. Because the location discourages people from seeking timely help, many buttock lesions go undiagnosed longer than similar problems elsewhere on the body, which can complicate treatment.
Folliculitis, Boils, and Abscesses
The single most common reason for a painful lump on the buttock is a bacterial skin infection. Folliculitis, where one or more hair follicles become inflamed and infected, produces small red bumps that look like acne. When bacteria push deeper, the result is a boil (furuncle), a swollen, tender nodule filled with pus. Multiple boils that merge beneath the skin form a carbuncle. These infections characteristically develop in areas where skin rubs, causing discomfort and pain, with the buttocks being one of the most frequently affected sites.1Cochrane Database of Systematic Reviews. Interventions for bacterial folliculitis and boils (furuncles and carbuncles)
Most isolated boils resolve on their own or with warm compresses. A single boil that has been present for a few days, is smaller than a golf ball, and is not accompanied by fever generally does not need emergency care. Larger or deeper abscesses, however, usually require incision and drainage by a clinician. Antibiotics alone rarely clear an abscess that has already walled off pus, because the drug cannot penetrate the cavity effectively. The organism responsible is usually Staphylococcus aureus, including methicillin-resistant strains (MRSA), which has made recurrent buttock boils a familiar complaint in emergency departments.
Hidradenitis Suppurativa
When painful bumps on the buttocks or groin keep coming back, a condition called hidradenitis suppurativa (HS) is a strong possibility. HS is a chronic inflammatory disease defined by recurrent, inflamed nodules in skin-fold areas such as the armpits, groin, and perianal region. In severe stages it can lead to the formation of sinus tracts, tunnels beneath the skin, and extensive scarring.2PubMed Central. Hidradenitis Suppurativa: Causes, Features, and Current Treatments Multiple pathogenic mechanisms have been proposed, including immune dysregulation, genetics, smoking, and obesity, but the exact cause has not been pinned down.
HS is frequently mistaken for ordinary boils, and the average patient sees several doctors over years before getting the correct diagnosis. The distinction matters because HS is not simply an infection. Standard antibiotics and drainage may temporarily help flares, but they do not address the underlying inflammatory cycle. Treatments aimed at controlling inflammation, from specific antibiotic regimens to biologic medications, are more effective long-term. One practical clue: if you keep getting “boils” in the same general area and they leave scars or connect under the skin, bring up HS specifically with your doctor.
Beyond the physical symptoms, HS carries a heavy psychosocial burden. Even though clothing can conceal the affected areas, the active condition is associated with malodorous discharge that stains clothing, leading to embarrassment, social stigma, low self-worth, and strain on relationships.3Postgraduate Medical Journal. Hidradenitis suppurativa: a common and burdensome, yet under-recognised, inflammatory skin disease People with severe HS sometimes avoid work and social situations entirely during flare-ups.
Pilonidal Cysts and Sinuses
A pilonidal cyst is a pocket in the skin at the top of the buttock crease, near the tailbone, that fills with hair and debris. When it becomes infected it turns into a painful, swollen abscess that may drain foul-smelling pus. The condition is most common in young men, especially those with coarse or abundant body hair, though anyone can develop one.
The prevailing explanation for how pilonidal disease forms centers on loose hairs being driven into the skin by friction and pressure. Karydakis’s model attributes the process to three factors: the loose hair itself, the force that pushes it into the skin, and the vulnerability of the deep natal cleft to hair insertion.4PubMed. Sacrococcygeal pilonidal sinus: historical review, pathological insight and surgical options Research supports this idea: patients with pilonidal sinus disease tend to have a deeper natal cleft than those without it, with one study measuring a mean cleft depth about 6 millimeters greater in affected patients.5Diseases of the Colon & Rectum. Natal Cleft Deeper in Patients with Pilonidal Sinus: Implications for Choice of Surgical Procedure
Pilonidal cysts can be confused with ordinary boils because they present similarly at first, but the location at the midline of the upper buttock crease is the giveaway. A single abscess can be drained, but recurrence is common and many people end up needing surgery to remove the sinus tract. Surgeons sometimes reshape the cleft to make it shallower, reducing the conditions that allowed the cyst to form in the first place.
Pressure Injuries
Pressure injuries, historically called bedsores or pressure ulcers, develop from sustained pressure and shearing forces on skin that is trapped between a bony prominence and a hard surface. They are most common in people who are bedridden, wheelchair-bound, or otherwise unable to shift their weight regularly.6PubMed Central. Pressure ulcers: Current understanding and newer modalities of treatment The sacrum (the flat bone at the base of the spine, right above the buttock crease) and the ischial tuberosities (the “sit bones”) are among the most vulnerable spots, making the buttocks the most frequent location for these wounds.
The underlying problem is straightforward: prolonged pressure collapses the tiny blood vessels that supply the skin. Without blood flow, the tissue dies. Loss of sensation, as occurs in spinal cord injury or severe neuropathy, compounds the issue because the person cannot feel the discomfort that would normally prompt them to shift position. Early-stage pressure injuries may look like a persistent red or darkened patch on the skin. Left untreated, they can progress to open wounds that expose muscle or bone. Advanced-stage pressure sores in the sacrococcygeal region are notoriously difficult to treat, sometimes requiring negative-pressure wound therapy, surgical debridement, and prolonged care.7PubMed. Effect of modified double negative-pressure wound therapy combined with debridement and tension-reduced suture in treatment of patients with stage 4 pressure sores and infection in sacrococcygeal region and its surrounding area
For caregivers, the practical takeaway is that repositioning a person in bed or a chair every couple of hours is the single most important preventive measure. Specialty mattresses and cushions help distribute weight more evenly, and keeping the skin clean and dry reduces breakdown. Once a pressure injury has started, it will not heal if the pressure that caused it continues.
Fungal and Parasitic Infections
Fungal infections on the buttocks are less common than people expect. In a cross-sectional study of residents in long-term care facilities, only about 5 percent had tinea (ringworm) on the buttocks and roughly 2 percent had candidiasis (yeast infection) in that area, far lower than the rates of fungal infections on the feet.8PubMed. The prevalence of skin eruptions and mycoses of the buttocks and feet in aged care facility residents: a cross-sectional study That said, candidiasis of the buttock crease does occur, particularly in people who are incontinent, obese, or on prolonged antibiotics. It typically presents as a bright red rash with smaller “satellite” patches at the margins, and it responds to topical antifungal creams.
Parasitic causes are less frequent in temperate climates but worth knowing about. The most commonly encountered parasites in the skin include the scabies mite, the jigger flea (Tunga penetrans), and fly larvae that cause myiasis.9Advances in Anatomic Pathology. Parasitic Infections of the Skin and Subcutaneous Tissues Scabies can affect the buttocks and produces intensely itchy burrows that are worse at night. Myiasis, where a fly larva grows under the skin and creates a boil-like nodule, is seen primarily in travelers returning from tropical regions. The key clue is a sensation of movement inside the lump.
Viral Infections and Herpes
Herpes simplex virus can cause lesions on the buttocks, and this is a more common location than many people realize. Initial episodes often present as a cluster of painful blisters that break open into shallow ulcers. In immunocompromised individuals, herpes can behave atypically, burrowing into deeper tissue and mimicking other conditions. A study of deep herpes infections found that the buttocks and perianal region was the most common site involved, and ulceration was a frequent finding. Notably, pyoderma gangrenosum, a completely different inflammatory ulcer, was the initial clinical suspicion in half of the specimens studied.10The American Journal of Surgical Pathology. Deep Herpes That overlap underscores how tricky diagnosis can be when herpes does not follow its usual pattern.
Shingles (herpes zoster) can also appear on the buttocks when the reactivated virus affects the sacral nerve roots. The rash follows a band-like pattern on one side only, which distinguishes it from other causes. Pain often precedes the rash by a day or two, so someone may feel a burning or aching sensation on one buttock before anything is visible.
Crohn’s Disease and Other Systemic Conditions
Not every buttock lesion originates in the skin. Crohn’s disease, a chronic inflammatory bowel condition, frequently produces perianal and buttock problems. Perianal disease is a common manifestation, sometimes even the presenting symptom before any gut-related complaints arise.11PubMed. Perianal Crohn’s disease In a review of 138 Crohn’s patients, about 44 percent had skin complications including abscess formation and ulceration in the perianal regions and groin.12British Journal of Dermatology. DERMATOLOGICAL MANIFESTATIONS OF CROHN’S DISEASE
There is also a rarer phenomenon called metastatic Crohn’s disease, where granulomatous inflammation appears in locations completely separate from the digestive tract. This can produce nodules, ulcers, or plaques on the buttocks, thighs, or elsewhere. In children, metastatic Crohn’s disease can actually precede gastrointestinal symptoms by months or even years.13PubMed. Cutaneous manifestations of metastatic Crohn’s disease A persistent, unexplained ulcer or granulomatous nodule on a child’s buttock, especially when standard treatments fail, should prompt consideration of underlying bowel disease.
Cutaneous tuberculosis is another systemic condition that can present as a skin lesion nearly anywhere on the body, including the buttocks. It is rare even in regions where tuberculosis is prevalent, and its many clinical appearances make it easy to mistake for other dermatological conditions.14PubMed Central. Cutaneous tuberculosis: a practical case report and review for the dermatologist
When to Worry About Cancer
Most buttock lumps are benign. Lipomas (soft fatty masses), epidermoid cysts, and fibromas are common and harmless, though they can be annoying. However, soft-tissue sarcomas and other malignancies can occasionally present as a mass in the buttock. A case report described a 23-year-old woman who found a slightly painful subcutaneous mass in her left buttock. After local excision, the wound refused to heal, did not respond to antibiotics, and the tumor progressed rapidly; the mass turned out to be a synovial sarcoma.15PubMed Central. Synovial sarcoma of the buttocks presenting with a non-healing wound and rapid progression after local resection: a case report
Red flags for a buttock mass that warrants urgent evaluation include rapid growth over weeks, a firm or hard consistency that is fixed to deeper tissue, a wound that does not heal despite appropriate care, and any mass larger than about 5 centimeters. Skin cancers such as squamous cell carcinoma can also develop on the buttocks, particularly at the edges of chronic non-healing wounds like longstanding pressure injuries or burn scars. These are sometimes called Marjolin’s ulcers.
Necrotizing Fasciitis and Other Emergencies
The most dangerous scenario involving a buttock lesion is necrotizing fasciitis, a rapidly spreading infection that destroys the soft tissue beneath the skin. Early symptoms overlap with those of ordinary cellulitis or an abscess, making it difficult to recognize in time. Patients typically experience pain out of proportion to what the skin surface looks like, swelling that extends rapidly, and systemic signs like fever and fast heart rate. Ultrasound can sometimes aid early diagnosis by detecting subcutaneous gas and fluid tracking along the fascial planes.16PubMed Central. A necrotising fasciitis: case report Necrotizing fasciitis requires emergency surgery and intravenous antibiotics. Delays of even hours can be fatal. If a buttock infection is accompanied by rapidly expanding redness, severe pain, skin discoloration that looks dusky or purplish, or crepitus (a crackling sensation under the skin), go to an emergency room immediately.
Cosmetic Injection Complications
Gluteal augmentation with injectable fillers has surged in popularity, and with it has come a rising number of complications that present as lesions on the buttocks. Silicone injections, especially those performed outside regulated clinical settings, can cause painful erythema, progressive fibrosis, and swelling that may not appear until years after the initial procedure. One reported case involved a 31-year-old woman who developed symptoms 11 years after receiving a gluteal silicone injection, ultimately diagnosed with a post-filler autoimmune syndrome.17PubMed Central. Complications of Silicone Fillers in Gluteal Augmentation: An Unusual Case of Filler Migration and Granuloma Formation
Newer fillers marketed as biocompatible have their own problems. Aquafilling filler, once promoted as safe for soft-tissue augmentation, has been associated with a growing number of long-term complications in the gluteal region.18PubMed Central. Long-term Complications of Gluteal Augmentation Using Aquafilling Filler: A Case Report Granulomas, which are hard nodules the body forms around foreign material, can develop months or years after injection and are difficult to treat. Filler migration from the buttocks into surrounding tissue adds another layer of complexity. If you have a history of any kind of buttock injection and develop new lumps, pain, or skin changes in the area, mention the injection history to your doctor even if the procedure was a long time ago.
Buttock Lesions in Infants and Children
The buttock region is one of the most common sites for skin problems in infants, and the differential diagnosis is broader than “diaper rash.” Rashes in the anogenital and buttock region are among the most frequent dermatological complaints in infancy. The most common causes are ulcerating hemangiomas, bullous impetigo, and severe irritant contact dermatitis. Less common possibilities include nutritional deficiencies, bullous diseases, Langerhans cell histiocytosis, and inflammatory disorders such as pyoderma gangrenosum.19PubMed. Anogenital and buttock ulceration in infancy Parents should seek medical attention for any infant buttock lesion that ulcerates, blisters, does not respond to standard diaper rash treatments within a few days, or is accompanied by fever or poor feeding.
Hemangiomas in the diaper area deserve special mention because they carry a risk of ulceration, and an ulcerated hemangioma on an infant’s buttock can be intensely painful, disrupting sleep and feeding. Early referral to a pediatric dermatologist can help, as treatments exist to shrink hemangiomas before they ulcerate.
Saddle Sores and Activity-Related Lesions
Cyclists, horseback riders, and others who spend long periods seated on hard or narrow surfaces are prone to saddle sores, friction-induced skin lesions on the buttocks, perineum, and inner thighs. Among female competitive cyclists, saddle sores are reportedly frequent, with prevention strategies including topical creams, maintaining good hygiene, wearing appropriate padded shorts, elevating the legs after rides, and taking time off the bike when sores develop.20PubMed. Saddle sores among female competitive cyclists: A systematic scoping review Saddle sores can progress from mild chafing to deep abscesses if ignored, so early intervention pays off. A properly fitted saddle, clean chamois, and post-ride showering reduce the risk considerably.
Contact sports can also produce buttock lesions through a different mechanism. “Mat herpes” or herpes gladiatorum, transmitted through skin-to-skin contact during wrestling, can appear on any body surface that made contact with an infected opponent, including the buttocks. Turf burns from artificial playing surfaces sometimes lead to secondary bacterial infections that look worse than the original abrasion.
Getting the Right Diagnosis
The challenge with a buttock lesion is that many different conditions look similar at first glance. A painful red lump could be a boil, an HS nodule, a pilonidal abscess, an infected cyst, or, rarely, something more serious. A few questions help narrow the field quickly:
- Where exactly is it? Midline at the top of the crease points toward pilonidal disease. Skin folds suggest HS or candidiasis. Over a bony prominence in someone with limited mobility suggests a pressure injury.
- Is this the first time, or does it keep coming back? Recurrence in the same general area is the hallmark of HS and pilonidal disease, both of which need different management than a one-off boil.
- How fast is it changing? A lump that doubles in size over hours with spreading redness and severe pain needs same-day medical evaluation to rule out necrotizing fasciitis or a rapidly enlarging abscess.
- Are there other symptoms? Fever, weight loss, night sweats, or gut symptoms accompanying a buttock lesion raise the possibility of a systemic cause like Crohn’s disease or tuberculosis.
Clinicians often rely on clinical appearance and history alone for straightforward cases. When a lesion does not behave as expected, imaging and biopsy become important. Ultrasound can distinguish a fluid-filled abscess from a solid mass and detect gas in the tissue that suggests necrotizing infection. Biopsy is reserved for atypical, non-healing, or suspicious lesions, and can reveal diagnoses like granulomatous inflammation, viral inclusion bodies, or malignancy that clinical examination alone cannot confirm.
Embarrassment about the location delays many people from seeking care. It is worth remembering that clinicians evaluate buttock lesions routinely, and early assessment almost always leads to simpler treatment. A boil caught early might need only warm soaks; the same infection left to expand for a week could require surgical drainage and leave a scar.