Melanosis of the thighs is generally caused by friction, and there is also the possibility of having acanthosis nigricans and post-inflammatory hyperpigmentation. The treatment is basically the same, with medication and physical therapy as the main treatment. The physiological cause of thigh melanosis is generally due to friction, and there are also pathological causes such as acanthosis nigricans and post-inflammatory hyperpigmentation, and the treatment is basically the same regardless of the cause. 1. Drug treatment: patients can apply niacinamide, azelaic acid and other drugs to inhibit melanocyte proliferation under the guidance of the doctor, and can also apply hydroquinone, tretinoin and other drugs to inhibit tyrosinase activity. If there is no pregnancy program, you can also follow the doctor’s instructions to apply retinoic acid cream, adapalene gel and other drugs to promote epidermal cell renewal. 2. Physical therapy: Physical therapy includes chemical peeling and laser therapy. Chemical peeling is to apply the peeling agent to the local area, and through the action of chemical substances on the surface layer of the skin, so as to promote the reconstruction of the local epidermis, and reduce the hyperpigmentation. Secondly, you can also choose laser treatment, which provides selective photothermal action on melanin, thus fading the melanin. If there is melanin pigmentation on the thighs, if you feel that it is not beautiful enough, it is recommended to go to the hospital and cooperate with the doctor to standardize the treatment.