Tinea cruris can be regarded as a special type of ringworm that occurs on the upper inner side of the femur. Its pathogenic bacteria to flocculent epidermolysis bullosa is common, other dermatophytes can also cause disease. Mostly seen in the groin area, unilateral or bilateral occurrence, also often occurs in the buttocks. The basic lesions are the same as tinea corporis, and because the affected area is poorly ventilated, moist, and prone to friction, the lesions are often markedly inflamed and itch significantly. Tinea cruris is usually caused by tinea pedis or tinea cruris itself, and the condition is related to seasonal changes, usually recurring or aggravated in summer and relieved in winter. The course of the disease is lingering, must be patient treatment can be cured, otherwise easy to recur. Ringworm and ringworm compared with the following points of difference: First, ringworm damage morphology is rarely round or oval, mostly irregular or arc; second, ringworm lesions often manifested as moss-like changes or acute and subacute eczema-like changes; third, ringworm is more likely to be complicated by bacterial infections; fourth, ringworm is itchy and more intense.