The diagnosis of typical tinea cruris is not difficult, mainly based on the symmetrical or unilateral occurrence of well-demarcated circumscribed inflammatory lesions on the pubic and femoral regions, with disseminated papules, blisters, and scales around the edges, and the fungi can be detected by taking the scales and blisters and doing a direct microscopic examination, which has a high rate of positivity. Diagnostic criteria: 1, often occurs in the skin of the thigh opposite the scrotum, one side or both sides, more common in men. 2, the lesions are mostly ring-shaped or semi-ring-shaped plaques, which are flaky and gradually expand and spread in all directions, with clear borders, which are covered with papules, blisters and crusts. The central part can be self-healing, with hyperpigmentation or flaking, for a long time in the local skin infiltration and thickening of mossy. 3, often accompanied by itching. 4, jock itch is a skin disease that occurs in the femoral area, and sometimes it can also involve the perineum, pubic mound, perianal area, buttocks, scrotal folds, etc. The itching is intense, and due to scratching, the patient can secondary dermatitis, tinea versicolor changes or secondary infections.