Abscesses on the buttocks are almost always caused by bacterial infections, most commonly a type of bacteria called Staphylococcus aureus. The infection takes hold when bacteria enter the skin through a hair follicle, a small cut, or a clogged gland, then multiply in the tissue and trigger an immune response that produces a painful, pus-filled pocket. But the specific reason an abscess forms in this area depends on exactly where it shows up and what’s going on beneath the skin.
Infected Hair Follicles
The buttocks are covered in hair follicles, and these follicles are the most common entry point for bacteria. The process usually starts with folliculitis, a shallow infection right at the surface of a follicle. If the infection pushes deeper into the skin, it becomes a boil (also called a furuncle), which is essentially a small abscess. When several neighboring follicles become infected and merge, the result is a larger, deeper mass called a carbuncle.
Friction plays a major role. Sitting for long stretches, wearing tight clothing, and sweating create the perfect conditions for bacteria to work their way into follicles. Shaving or waxing the area can also nick follicles and open the door to infection. Once bacteria are inside, the body walls off the infection with inflammatory tissue, and pus accumulates as white blood cells fight the invading organisms.
Pilonidal Cysts Near the Tailbone
Abscesses that form right along the crease between the buttocks, near the tailbone, are often pilonidal cysts that have become infected. These start when loose hairs puncture the skin and get embedded beneath the surface. The body recognizes the hair as foreign and forms a cyst around it in an attempt to push it out. When bacteria colonize that cyst, it swells into a painful abscess.
Friction and pressure drive hairs into the skin in this area. Cycling, sitting at a desk for hours, and wearing tight pants all increase the risk. People who are overweight, have thick or coarse body hair, or lead a sedentary lifestyle are more likely to develop pilonidal abscesses. The condition is especially common in young men and tends to recur.
Perianal Abscesses
An abscess that appears close to the anus has a different origin than one on the outer buttock. The anal canal contains small glands, and when one of these glands gets clogged, bacteria or stool can become trapped inside, leading to infection. The resulting perianal abscess tends to be intensely painful, especially during bowel movements, and can cause fever.
Other triggers for perianal abscesses include an infected anal fissure (a small tear in the lining of the anus), trauma to the area, sexually transmitted infections, and inflammatory bowel conditions like Crohn’s disease. These abscesses almost always require professional drainage and can develop into an abnormal tunnel between the anal canal and the skin surface if left untreated.
Hidradenitis Suppurativa
When abscesses keep coming back in the same spots on the buttocks, groin, or underarms, the underlying cause may be hidradenitis suppurativa, a chronic skin condition that’s often mistaken for acne or recurring boils. It involves repeated inflammation and infection of hair follicles and sweat glands, leading to painful lumps, abscesses, and sometimes tunnels beneath the skin that drain fluid.
The pattern is the key clue. A one-time abscess from an infected follicle is common and usually straightforward. But if you’re getting abscesses in the same locations over months or years, especially in skin folds where skin rubs together, that recurring pattern points toward hidradenitis suppurativa rather than simple boils. No lab test confirms it. Diagnosis is based on the appearance of the skin, the location of the lumps, and whether they keep returning.
The Role of Staph Bacteria and MRSA
Staphylococcus aureus is responsible for the majority of skin abscesses. This bacterium lives harmlessly on the skin and inside the nose of about a third of the population. It only causes problems when it gets beneath the skin’s surface through a break, cut, or follicle opening.
A growing concern is MRSA, a strain of staph that resists many common antibiotics. Between 2009 and 2011, roughly 46% of staph-related skin infections in the United States were caused by MRSA, up from 36% just a few years earlier. MRSA abscesses look and feel identical to regular staph abscesses, but they’re harder to treat with standard antibiotics. Community-acquired MRSA, meaning infections picked up outside hospitals, has become increasingly common and is a frequent cause of buttock abscesses in otherwise healthy people.
Risk Factors That Make Abscesses More Likely
Some people are simply more prone to buttock abscesses because of underlying health conditions or lifestyle factors:
- Diabetes: Skin infections occur in 20% to 50% of people with diabetes. High blood sugar impairs circulation, reduces the immune response, and damages small blood vessels, all of which make it harder for the body to fight off bacteria that enter the skin. Boils, carbuncles, and folliculitis tend to be more severe and widespread in people with poorly controlled blood sugar.
- Obesity: Excess weight increases friction and moisture in skin folds, creating warm, damp environments where bacteria thrive.
- Weakened immune system: Conditions or medications that suppress the immune system reduce your body’s ability to contain infections before they form abscesses.
- Prolonged sitting: Pressure on the buttocks compresses hair follicles and traps sweat against the skin, increasing the chance of infection.
- Poor hygiene or shared personal items: Bacteria like MRSA spread easily through shared towels, razors, or athletic equipment.
What Happens if an Abscess Goes Untreated
Small abscesses under 2 centimeters that are already draining on their own can sometimes be managed with close observation. But most abscesses need to be professionally drained. Antibiotics alone typically can’t clear an abscess because the drug has difficulty penetrating the walled-off pocket of pus.
Left untreated, a buttock abscess can grow, deepen, or spread the infection into surrounding tissue. Systemic signs like fever above 100.5°F, rapid heart rate, or red streaks spreading outward from the abscess indicate the infection may be moving into the bloodstream. At that point, the situation becomes more serious and may require intravenous antibiotics in addition to drainage.
Reducing the Risk of Recurrence
If you’ve had one buttock abscess, your chances of getting another are higher, particularly if you carry staph bacteria on your skin. Keeping the area clean and dry is the most basic preventive step. Wearing loose, breathable clothing reduces friction. Avoid sitting on hard surfaces for extended periods without breaks, and change out of sweaty workout clothes promptly.
For people with recurrent staph infections, a decolonization routine can help. This involves using an antiseptic body wash (chlorhexidine is the most studied option) and applying an antibiotic ointment inside the nostrils for five days, since the nose is the primary reservoir where staph bacteria live. This combination reduces the bacterial load on the skin and lowers the odds of reinfection. Your doctor can walk you through the specific protocol if abscesses keep returning.