Melanin deposits on the back of the neck can be both a symptom caused by physiological factors such as friction, and a symptom caused by diseases such as acanthosis nigricans and post-inflammatory hyperpigmentation. Patients can eliminate it through general treatment, medication and physical therapy. 1. Physiological factors: patients with melanin deposits on the back of the neck caused by friction generally do not need to take special treatment. Patients need to avoid long-term local friction and wear loose clothes in daily life. For patients with treatment needs, hydroquinone cream can be applied locally to remove localized melanin deposits. 2. Acanthosis nigricans: Acanthosis nigricans is a skin disease characterized by symmetrically distributed hyperpigmentation and velvety thickening. Patients can follow the doctor’s instructions to use topical Vitamin A drugs, such as Vitamin A acid gel, tazarotene gel and so on. Patients with ineffective drug treatment can use laser, electrocautery therapy and other physical treatment means. 3. Post-inflammatory hyperpigmentation: Melanin deposits on the skin of the neck may also be a symptom of post-inflammatory hyperpigmentation. Patients can use drugs that inhibit the proliferation of melanocytes, such as azelaic acid ointment, tranexamic acid, etc., or drugs that inhibit tyrosinase activity, such as hydroquinone cream, etc., under the guidance of a doctor. Patients can also use physical therapy such as laser. All of the above drugs should be used under the guidance of a doctor. Patients with melanin deposits on the back of the neck should consult a doctor in time to find out the cause of the disease and under the guidance of a physician.