The black folds of the skin in the groin are considered to be ringworm, chronic eczema and acanthosis nigricans, which are mainly treated with medication, according to the specific causes of the disease, and choose the appropriate treatment method. 1. Ringworm: ringworm is a fungal infectious disease that occurs in the groin area, there will be erythema, pimples, scales, itching and other symptoms, the long course of the local skin thickening is mossy, manifested in the skin black folds. The main treatment is the use of antifungal drugs, you can apply miconazole, econazole, amorolfine cream, etc., but also oral terbinafine, itraconazole and so on. 2. Chronic eczema: chronic eczema will appear rough and hypertrophic skin, mossy changes, manifested as black folds of the skin, mainly applying glucocorticoid drugs, such as budesonide cream, tretinoin cream, etc., and after the condition is under control, you can change to use calcium-modulated neural phosphatase inhibitors, such as tacrolimus ointment, pimecrolimus cream. 3. Acanthosis nigricans: mostly related to heredity, obesity, etc. It can be manifested as darkening and thickening of skin folds, such as armpits and groin, and it can also cause black skin folds. At this time, we need to clarify the cause of the disease, such as due to obesity, need to control body weight; such as due to tumors, need to clarify the nature of the targeted treatment. At the same time, hydroquinone cream can be used externally to improve hyperpigmentation, vitamin A cream can be used externally to improve the thickening of the skin, and vitamin A and other drugs can also be taken orally. The groin skin black folds to the cause of the symptomatic treatment, the above drugs should be used in accordance with the doctor’s instructions, can not blindly use their own.