The back is always itchy may be too exuberant secretion of sebum lead to folliculitis, but also may be the alternation of seasons caused by dry skin, at the same time to exclude the risk of organic diseases such as chronic liver disease. 1. Folliculitis: adolescents in puberty due to hormonal changes in the body, the body oil secretion is more exuberant, and the distribution of sebaceous glands in the back is more dense, so it is easy to be infected by pathogenic bacteria and folliculitis, manifested by itching, erythema papules, and other symptoms, the patient should be treated in a timely manner. 2. Dry skin: because patients do not do a good job of skin moisturizing measures during the alternation of autumn and winter seasons, the skin lacks moisture, dry, so there will be itchy skin symptoms, patients can usually apply body lotion to improve this symptom. 3. Chronic diseases: if the patient suffers from certain endocrine diseases such as chronic liver disease, diabetes, etc., there will also be itchy skin symptoms, need to treat the original disease. Itchy back skin alone can not accurately determine the cause, but also need to be combined with other test results to make an accurate judgment, it is recommended that the cause of the disease under the guidance of a doctor.