The dark brown color of the skin at the junction of the back of the neck and the roots of the hair is considered to be post-inflammatory hyperpigmentation, acanthosis nigricans, Rielle’s melanosis, etc. The main treatment methods are medication, etc., and the appropriate medication should be chosen according to the cause of the disease. 1. Post-inflammatory hyperpigmentation: if you work outdoors for a long time, the back of your neck is often exposed to ultraviolet radiation, which can cause solar dermatitis, and after the inflammation subsides, it can lead to hyperpigmentation, which makes the local color dark brown, and this situation doesn’t need any special treatment, and you should pay attention to good sun protection. 2. Acanthosis nigricans: Acanthosis nigricans may be related to heredity, metabolism, etc., which is manifested as deepening of local skin color, thickening, roughness and wart-like small protrusions. You can follow the doctor’s instructions to find the cause of the disease and correct the cause of the disease in time, but also under the guidance of the doctor can be applied locally Vitamin A acid gel, hydroquinone cream, cod liver oil ointment and other treatments. 3. Rielle’s melanosis: the cause of the disease is unknown, can appear in the face of gray-purple network pigmentation spots. Patients can apply hydroquinone cream, compound arbutin cream, etc. under the guidance of the doctor; those with severe inflammation can apply glucocorticosteroids, such as hydrocortisone cream, etc., and can take oral tranexamic acid tablets, etc.; or follow the doctor’s instructions to use laser treatment to alleviate the symptoms. It is recommended that the back of the neck and the junction of the hair roots of the skin color dark brown symptoms of patients go to the hospital in a timely manner to clarify the cause of the disease, standardized treatment, the above drugs should be used in accordance with the doctor’s instructions.