A boil on the buttocks is a pus-filled skin infection that starts in a hair follicle or oil gland. The most common cause of boils on the buttocks is a bacterial infection, usually by Staphylococcus aureus (S. aureus) . Scratches, small nicks in the skin, popping a pimple, or even bug bites create openings for bacteria to enter a follicle, which starts an infection and causes the boil to grow as pus forms. Other factors that can make some people more likely to experience boils on their butt include a weakened immune system from other health conditions such as diabetes or cancer, conjunctivitis, eczema, or allergic asthma, and skin folds due to being overweight.

Boils on the buttocks usually look like red bumps or lumps on the skin, and over time they fill with pus. They can be painful, tender, swollen, warm, and filled with pus. Boils often occur on the buttocks because areas of the body that have hair, sweat, and friction are more likely to have boils.

Home remedies and certain medications may help heal the boil, but larger boils may require a visit to a healthcare professional. It is important not to pick or pop a boil due to the increased risk of spreading the infection. If a boil on the buttocks does not improve with warm compresses after a few days, it may be helpful to consult a doctor. A person should see their doctor sooner if the boil becomes larger, becomes streaked, or makes sitting too painful.