Acne on the back should be eliminated with appropriate treatments according to the cause: folliculitis can be treated with topical mupirocin ointment, ketoconazole cream, etc.; acne can be treated with topical adapalene gel, retinoic acid ointment, etc. 1. Folliculitis: Most of them are due to bacterial infections such as Staphylococcus aureus, or Malassezia infection, which causes inflammatory reaction of hair follicles, and will lead to the symptom of acne on the back. Bacterial infections can be treated with antibiotic drugs such as topical mupirocin ointment; Malassezia infections can be treated with topical ketoconazole cream, ketoconazole lotion and other drugs. 2. Acne: Excessive secretion of androgens and increased oily secretions from hair follicles can cause acne, leading to back acne. Adapalene gel, retinoid ointment and other drugs can be used externally. Oral medication such as minocycline is needed when the inflammatory reaction is significant. If you have acne on your back, it is recommended that you go to the hospital first to get a clear examination of the cause of the problem, and all medications need to be used under the guidance of a professional doctor, so you can’t abuse the medication on your own.