A lot of red bumps on the buttocks may eczema, ringworm, contact dermatitis and other causes. 1. eczema: is caused by a variety of internal and external factors of a kind of skin inflammatory reaction, mainly manifested as skin papules, papules, redness, swelling, itching, vesicles, oozing and other symptoms, if the hair in the femoral part, can cause a lot of red bumps on the buttocks. 2. ringworm: refers to occur in the thigh roots, perineum, perianal and buttocks dermatophyte infection, mainly manifested as scaly red patches in the femur, and accompanied by itching and other discomforts, which can also cause a lot of red bumps on the buttocks. 3. contact dermatitis: such as patients allergic to underwear material or young children allergic to diapers, etc., can cause acute or chronic inflammatory reaction at the contact site, which can lead to contact with the site of erythema, papules, or even redness, blisters, etc., which can be accompanied by itching, burning sensation, etc., which can also cause a lot of red bumps on the buttocks. There are many other causes of red bumps on the buttocks, should be taken seriously, timely consultation, identify the cause of the disease, and follow the doctor’s instructions for further treatment or therapy.