Ringworm is most often transmitted by direct contact from scratching tinea pedis, ringworm of the femur, ringworm of the head, etc. or the spread of tinea nail and tinea corporis on the back of the hand. The causative agent of ringworm is mainly Trichophyton rubrum, accounting for about 55.6% of cases, followed by Trichophyton rubrum plasteri, accounting for about 22.7%. Candida albicans can also cause the same damage as tinea cruris. In addition to dermatophytes, it is also associated with long-term scratching, washing and scalding, soaps and detergents, irritation by various chemicals and solvents, and inappropriate treatment. Western medical etiology: The pathogenic bacteria are basically the same as those of tinea pedis. However, because the hand is an exposed area, it does not produce the impregnated eruption type. Finger vesicles are often caused by Candida albicans, rather than ringworm in general. The pathogenic bacteria of tinea cruris are mostly ringworm red, ringworm flocculent epidermidis, ringworm plaster-like, or Candida albicans. Pathogenesis: Same as ringworm, impermeable clothing increases the local temperature and humidity of the skin and interferes with the barrier function of the stratum corneum. After Trichophyton rubrum red and Trichophyton spp. invade the skin, they have to go through several developmental stages, including the incubation period, enlargement and degeneration during the anti-infection process. The incubation period grows in the stratum corneum and the clinical manifestations are mild. Once the infection is established, the growth rate of Trichophyton rubrum and Trichophyton spp. and The rate of epidermal renewal is two critical factors for the development of damage, both must be equal or greater than the former, otherwise the number of Trichophyton rubrum and Trichophyton spp. will decline and the keratinase and other proteolytic enzymes produced by Trichophyton rubrum and Trichophyton spp. will not only colonize and invade the skin with them, but also manifest as skin damage.