Acne on the body may be caused by acne, sebaceous cysts, folliculitis and other diseases. 1. Acne: It may be related to androgen levels, exuberant sebaceous gland secretion, Propionibacterium acnes infection, abnormal keratinization of cells around hair follicles and other causes. It can be manifested as pimples, inflammatory papules, pustules, etc. It is most common on the trunk such as the chest and back, and facial areas such as the jaw and forehead. 2. Sebaceous cysts: mainly due to the severe blockage of the sebaceous glands of the hair follicles, the accumulation of sebum accumulates into cysts. Since the sebaceous glands are distributed all over the body, sebaceous cysts, which are round like grains of rice, may appear on the back and buttocks, and may be manifested as inflammatory papules. 3. Folliculitis: mainly caused by bacterial and fungal infections. Common triggering factors are hair follicle injury, decreased immunity, obesity and so on. The manifestation of red papules, single hair follicles of infection fusion can form larger inflammatory papules or pustules. Patients with acne on the body need to go to the hospital, to clarify the cause of the disease, under the guidance of the doctor for treatment.