Buttocks refers to the buttocks, on which grow many red bumps, common causes include: folliculitis, ringworm, contact dermatitis, etc.. 1. Folliculitis: mostly related to the lack of attention to skin cleaning, sweating, infection and other factors, resulting in an inflammatory reaction of the hair follicles, which in turn causes the local skin to appear red bumps performance. 2. ringworm: mainly caused by pathogenic fungal infections, can also be spread by ringworm, tinea pedis, its main manifestations of the buttocks appear a lot of red bumps, and often accompanied by erythema, small blisters and other symptoms. 3. contact dermatitis: because of the buttocks skin contact with some sensitizing or stimulating substances after the occurrence of allergic or stimulating reaction, thus causing the buttocks skin erythema, pimples, blisters, itching and other manifestations. In short, the buttocks grow a lot of red bumps, it is recommended that timely medical treatment, and follow the doctor’s instructions for treatment, in daily life, to keep the buttocks skin clean and dry, and change underwear diligently.