Tinea capitis first appears as a flushed, small papule on the inside of the femur near the scrotum, followed by the formation of small white scales on top of the papule, with the rash gradually spreading around. Tinea cruris is a skin disease caused by a fungal infection of the inner femur, perineum, and buttocks. The main symptom is significant localized itching. The disease is prone to recurrence. It is mostly transmitted through contact with patients with ringworm, through cats and dogs, indirectly through clothing and utensils, or by scratching and spreading from tinea pedis. In summer, when the climate is hot and humid, the human body sweats a lot, especially in the femur, and if you do not take a bath in time or wear tight underwear with a lot of sweat that does not evaporate in time, you are prone to get this disease. In addition, patients suffering from diabetes, excessive leukorrhea, etc., as well as long-term oral or topical application of a large number of broad-spectrum antibiotics or corticosteroids, are also susceptible to ringworm. In terms of incidence, it is mainly in young people and more in men than in women. The disease occurs mostly in summer, and the humid or hot climate tends to aggravate the condition, which is relieved or cured in winter. The main pathogenic bacteria of tinea cruris are Trichophyton rubrum and Trichophyton spp. Tinea flocculata used to be a common pathogen of ringworm, but it has become less common in recent years. Some other pathogens that can cause ringworm can also be the cause of ringworm, but they do not account for a large percentage. In Chinese medicine, it is believed that the sweat sweat is caused by the external wind. 2. Pathogenesis The incidence of ringworm is relatively high because the femoral area is more suitable for fungal growth. Impermeable clothing can increase the local temperature and humidity of the skin and interfere with the barrier function of the stratum corneum. After Trichophyton rubrum and Trichophyton spp. have invaded the skin, they go through several developmental stages, including an incubation period, enlargement during the resistance to infection, and a degeneration period. The incubation phase grows in the stratum corneum and has mild clinical manifestations. Once the infection is established, the growth rate of Trichophyton rubrum and Trichophyton spp. and the rate of epidermal renewal are two critical factors for the development of the damage. The former must be equal or the former greater than the latter, otherwise Trichophyton rubrum and Trichophyton spp. numbers will decline. The keratinases and other proteolytic enzymes produced by Trichophyton rubrum and Trichophyton spp. not only colonize and invade the skin with them, but also manifest as skin damage.