Tinea corporis is a skin disease that affects the femoral area and sometimes the perineum, mons pubis, perianal area, buttocks, and scrotal folds. It itches intensely, and due to scratching, patients may develop secondary dermatitis, lichenified changes, or secondary infections. Characteristics: 1. At the beginning of tinea cruris, it is a slightly elevated erythematous spot with clear edges, which gradually expands and has flakes on it, and gradually changes from red to brown or skin color. 2, The center of the lesion gradually heals on its own and progresses to the periphery, and the edges of the erythema are more clearly inflamed and may have rashes, blisters, scabs, or even erosions on them, forming a ring. 3.After healing, it leaves temporary hyperpigmentation and severe itching symptoms. 4, Tinea corporis first appears as a flushed, small papule on the inner side of the femur near the scrotum, followed by the formation of small white scales on top of the papule, and the rash gradually expands to the surrounding area with clear boundaries. In the progressive phase, papules, blisters and scales may appear at the same time at the edges, and occasionally pustules are seen. Conscious itching varies greatly among individuals, from severe itching to no itching at all. Frequent scratching may result in mossiness and hyperpigmentation. The lesions may also extend to the lower abdomen, perineum and buttocks. The scrotum and penile skin may also be involved. 5. The disease is closely related to the seasons, and is prone to aggravation and itchiness in summer, while it can naturally remit and stabilize in winter. If the disease is not treated in time, it can persist for a long time. The diagnosis of typical ringworm is not difficult, mainly based on the presence of symmetrical or unilateral, well-defined, circumscribed inflammatory lesions on the pubic and femoral areas, with disseminated papules, blisters, and scales around the edges, and fungus can be detected by direct microscopic examination of the scales and blisters.