Melanosis on the back of the neck may be caused by physiological factors such as long-term exposure to the sun, or it may be caused by diseases such as acanthosis nigricans, post-inflammatory hyperpigmentation, etc., which can be improved by general treatment, medication and other means. 1. Physiological factors: If melanin deposits on the back of the neck are caused by long-term exposure to the sun, you need to pay attention to sun protection and avoid being exposed to ultraviolet rays. You can also use hydroquinone cream externally to inhibit melanin deposition. 2. Acanthosis nigricans: If acanthosis nigricans is the cause of melanin deposits on the back of the neck, the patient needs to pay attention to local cleanliness, dietary control, regular work and rest. Patients can follow the doctor’s instructions to use topical salicylic acid, which has the effect of dissolving keratin. You can also use topical retinoic acid ointment to inhibit melanin formation, but the drug has local irritation. 3. Post-inflammatory hyperpigmentation: melanin deposits on the back of the neck may be caused by post-inflammatory hyperpigmentation, and most of the patients with mild symptoms will subside on their own. Patients can follow the doctor’s instructions to use hydroquinone, tretinoin and other creams, which can inhibit tyrosinase activity. You can also use glycopyrrolate, tranexamic acid and other drugs to inhibit melanin production. There are many causes of melanin precipitation on the back of the neck, and it is recommended that the patient go to the hospital, and standardize the treatment after clarifying the cause of the disease.