Acne, folliculitis and other diseases may cause back acne. 1. Acne: The cause of the disease may be related to factors such as changes in androgen levels and large secretion of sebum, and the environment and diet may also trigger the disease. The main manifestations are pimples and pustules, which can be seen on the cheeks, back, chest and other locations. 2. Folliculitis: the cause of the disease is mainly related to pathogenic bacterial infection, immunity decline, skin damage and other factors may also induce the disease. It is mainly manifested as red papules centered on hair follicles, and it is easy to develop into pustules, which may be accompanied by itching, pain and other symptoms, and can be seen on the head and face, trunk, armpits and other parts. There are many causes of back acne, it is recommended to go to a regular hospital to clarify the cause of the disease.