A rash on the buttocks is usually caused by friction, trapped moisture, or contact with an irritant, though infections and chronic skin conditions can also be responsible. The area is especially prone to rashes because it stays warm, sweaty, and covered by clothing for most of the day. Most causes are treatable at home, but knowing what you’re dealing with helps you choose the right approach.
Contact Dermatitis
One of the most common causes is contact dermatitis, an itchy, burning, or stinging rash that develops when your skin reacts to something it touched directly. On the buttocks, the usual culprits include fragranced laundry detergent, fabric softener, scented toilet paper, wet wipes, or new underwear fabric. Some people react to dyes in clothing or the chemicals in dryer sheets. The rash typically shows up as red, inflamed patches in the area that had the most contact with the irritant.
If you recently switched any product that touches your skin or clothing, that’s the first thing to rule out. Switching to fragrance-free detergent and skipping fabric softener for a few wash cycles often clears this type of rash within a week or two.
Intertrigo: Friction and Moisture
Intertrigo is an inflammatory rash that forms where skin rubs against skin, and the buttock crease is one of its favorite locations. Trapped sweat causes skin surfaces to stick together in the fold. That moisture increases friction, which damages the outer layer of skin and triggers inflammation. The result is a reddish or reddish-brown rash that can itch, sting, or feel raw.
What makes intertrigo tricky is that the damaged skin often becomes a breeding ground for bacteria or fungus that already live on your skin’s surface. The warmth and moisture create an ideal environment for these organisms to multiply. Candida, a type of yeast, is the most common secondary infection. When yeast takes hold, the rash typically intensifies, with spreading borders, satellite bumps, and more intense itching.
Several factors raise your risk: obesity (which creates deeper skin folds and more sweating), diabetes (which can change your skin’s pH to favor fungal growth), excessive sweating, living in a hot and humid climate, and incontinence. People with excess skin after significant weight loss are also more prone to intertrigo because of the additional skin folds.
Yeast Infections
Candida lives on everyone’s skin and usually causes no problems. But when the buttock area stays warm and damp for too long, yeast can overgrow and cause an infection. This looks different from a simple friction rash. Yeast rashes tend to be bright red with well-defined edges and small “satellite” bumps or pustules just beyond the border of the main rash. The itching is often intense.
Tight, non-breathable underwear, sitting for long periods in sweaty clothes, and antibiotic use (which disrupts the balance of organisms on your skin) all make yeast overgrowth more likely. Over-the-counter antifungal creams containing clotrimazole or miconazole are the standard first treatment. Keeping the area dry and wearing breathable cotton underwear speeds recovery.
Folliculitis
If the rash looks more like scattered pimples or small red bumps centered around hair follicles, you’re likely dealing with folliculitis. The buttocks are a common site because of the combination of friction, sweating, and clothing pressure. Staphylococcus aureus bacteria are the most frequent cause, though other bacteria can be responsible too.
Tight pants, sitting on non-breathable surfaces for hours, shaving, and wearing sweaty workout clothes too long all contribute. The bumps may contain visible pus and can be tender to the touch. Mild folliculitis often resolves on its own within a week or two if you reduce friction, wear looser clothing, and gently wash the area with antibacterial soap. Resist the urge to squeeze the bumps, as this can push bacteria deeper.
Heat Rash
Heat rash happens when sweat ducts get blocked or inflamed, trapping sweat beneath the skin instead of letting it evaporate. This causes small, irritated bumps that may itch or prickle. In adults, heat rash tends to develop where clothing rubs against the skin and in skin folds, making the buttocks a common location.
Sitting in a hot car, exercising in humid weather, or wearing tight synthetic fabrics can all trigger it. The fix is straightforward: cool down, let the area air out, and switch to loose, breathable clothing. Heat rash usually clears within a few days once the skin can breathe.
Inverse Psoriasis
Not every persistent buttock rash is caused by something external. Inverse psoriasis is an immune-mediated condition where the body’s immune system mistakenly attacks healthy skin cells in the skin folds. It produces smooth, shiny red patches (unlike the scaly plaques of regular psoriasis) in the buttock crease, groin, and other fold areas.
Inverse psoriasis can look a lot like intertrigo or a yeast infection, which is why it’s often misdiagnosed. The key difference is that it doesn’t respond to antifungal creams and tends to come and go over months or years. A dermatologist may need allergy tests, blood work, or a small skin biopsy to distinguish it from other conditions. If you’ve been treating a buttock rash for weeks without improvement, this is one possibility worth investigating.
Herpes Simplex
Herpes simplex virus can cause sores on the buttocks, not just the genitals. The rash appears as small blisters or bumps that may break open into painful sores. Some people experience tingling or shooting pain in the legs, hips, or buttocks in the hours or days before a new outbreak, known as prodromal symptoms. Outbreaks tend to recur in the same general area. If you notice clusters of blisters rather than a broad rash, it’s worth getting tested.
Incontinence-Related Rash
Adults who manage urinary or fecal incontinence frequently develop irritation and raw skin on the buttocks. This is essentially a form of contact dermatitis caused by prolonged exposure to urine or stool in absorbent undergarments. The warm, moist environment also raises the risk of secondary yeast or bacterial infection. Barrier creams containing zinc oxide can help by forming a protective layer over the skin, shielding it from moisture while allowing it to heal. Apply a generous layer to clean, dry skin.
How to Tell What Type of Rash You Have
The appearance of the rash offers the best clues. A flat, red, irritated patch in a skin fold points toward intertrigo or contact dermatitis. Bright red patches with satellite bumps and intense itching suggest yeast. Scattered pimple-like bumps around hair follicles are typical of folliculitis. Clusters of small blisters that break open may indicate herpes. Smooth, shiny, well-defined red patches that don’t respond to antifungal treatment suggest inverse psoriasis.
Location matters too. Rashes confined to the crease between the buttocks are more likely intertrigo or yeast-related. Rashes spread across the cheeks are more consistent with contact dermatitis, folliculitis, or heat rash.
Signs That Need Medical Attention
Most buttock rashes are uncomfortable but not dangerous. However, certain signs point to something that needs professional evaluation. The American Academy of Dermatology flags these warning signs for any rash: spreading rapidly, blistering or turning into open sores, causing fever, or covering a large area of the body. Signs of infection include pus, yellow or golden crusts, increasing pain, swelling, warmth, and a foul smell. If the skin around the rash turns increasingly red, purple, or brown, or if you develop swollen lymph nodes, these suggest the infection is worsening and needs treatment beyond what over-the-counter products can provide.