Black finger joints can be caused by physiological or pathological reasons, the former can be gradually restored by removing the stimulating factors, and the latter needs to be improved by medication. 1. Physiological reasons: long-term friction may lead to blackened finger joints, this symptom does not affect health, but only to a certain extent affects the aesthetic appearance, the patient can remove the friction factors, do a good job of sunscreen, regular hand cleaning and apply urea ointment and other moisturizing agents to improve the symptoms. 2. Pathologic causes: (1) neurodermatitis: the disease can be caused by the blackened finger joints, patients should regulate their emotions, avoid emotional tension or anxiety, but also can follow the doctor’s instructions to apply halometasone cream, fluoride acetate easy cream and other glucocorticosteroid medication for treatment, the drug should not be used for a long period of time, to avoid the emergence of skin atrophy, hyperpigmentation and other adverse reactions. (2) Reel melanosis: it may be related to photosensitivity, mechanical stimulation, vitamin deficiency and other factors, and may appear as darkening of the knuckles. Patients should pay attention to sun protection, avoid re-exposure to photosensitizers, topical hydroquinone cream and other decolorizers, and in severe cases, oral glucocorticoid drugs such as prednisone can also be prescribed for treatment. (3) Diabetes mellitus: This disease can cause itching of the skin, and long-term scratching can also lead to darkening of the skin of the finger joints. Patients need to eat a low sugar diet, regular monitoring of blood glucose, oral metformin, acarbose and other hypoglycemic drugs as prescribed by the doctor, or subcutaneous injection of insulin and other drugs to control blood glucose, the original disease is under good control, but also reduce the symptoms of blackened knuckles. Finger joints black may also be caused by other diseases, it is recommended that patients go to the regular hospital dermatology consultation, after a clear diagnosis under the guidance of the doctor standardized treatment, it is possible to improve the joints of the skin black, make it white.