Acne on the back can be caused by mites, but also by Malassezia folliculitis, allergies and other causes. 1. Mites: When the skin on the back is bitten by mites, the local skin will show inflammatory reactions, such as pimples and blisters, accompanied by itching symptoms. 2. Malassezia folliculitis: occurs on the back, chest, shoulders and neck and other parts of the sebaceous glands, mainly manifested as follicular papules on the surface of the skin, surrounded by a red halo, interspersed with small pustules, accompanied by varying degrees of itching. 3. Allergy-prone people: allergy-prone people back in contact with certain clothing, mattresses, shower gels, etc., may trigger allergies, manifested as red papules, papules on the skin surface, accompanied by intense itching symptoms. In summary, back acne may be due to mites, but also may be caused by Malassezia folliculitis, allergies, etc. It is recommended to go to the hospital in a timely manner to improve the examination, to clarify the cause of the disease and then give targeted treatment. During the treatment period, the diet should be light, do not eat spicy stimulating food, and pay attention to not scratch the affected area, so as not to cause ulceration, secondary infection.