Ragged crotch usually refers to the appearance of erythema, papules, vesicles, oozing, etc. on the skin of the perineum and genital area, which may be caused by scrotal neurodermatitis, eczema, jock itch and other diseases. 1. Scrotal neurodermatitis: the disease may be related to mental factors, gastrointestinal function, etc. Thickening of the skin in the perineum, mossy changes, etc., accompanied by intense itching, bleeding, vesicles, oozing, scabs, etc., resulting in rotting crotch phenomenon after scratching. 2. Eczema: the cause of the disease is not known, may be related to heredity, immunity, infection, allergy and so on. It occurs in manual laborers, long-term sedentary people, etc. Due to the humidity and airlessness of the scrotum area, it can appear locally as erythema, pimples, and even vesicles and oozing, leading to the phenomenon of rotting crotch. 3. Ringworm: mainly due to dermatophyte infection, due to the perineum and genital area moisture, airtight, infected with fungi can appear locally erythema, flaking, can also be due to friction erosion, oozing, itching and other symptoms, leading to the phenomenon of rotten crotch. There are more diseases that cause crotch rot, also seen in contact dermatitis, syphilis and other diseases. Therefore, it is recommended that patients should seek medical treatment as soon as possible to avoid delayed treatment and aggravation of the condition.