Buttocks refers to the buttocks, on which small bumps grow itchy, consider folliculitis, ringworm, contact dermatitis and so on. 1. Folliculitis: folliculitis is an inflammatory skin disease mainly involving hair follicles, most of them are related to Staphylococcus aureus infection, mainly manifested as red pimples centered on hair follicles, and usually have symptoms such as itching and pain. 2. ringworm: due to fungal infection of the groin, perineum, buttocks skin caused by infectious skin diseases, can be manifested in these parts of the skin with erythema, pimples, scales, flaking, itching and other symptoms, so ringworm can also cause itchy bumps on the buttocks. 3. contact dermatitis: due to the buttocks skin contact with certain sensitizing or irritating substances caused by allergic or irritating reaction, can be manifested as erythema, papules, papules, blisters, etc., accompanied by itching, so the contact dermatitis can also cause small bumps on the buttocks itchy. Itchy bumps on the buttocks may also have other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, give targeted treatment or standardized treatment.