The condition of ringworm on the back of the neck is considered to be related to tinea corporis. The basic cause is dermatophyte infection, and there are also more triggering factors. 1. Basic cause: the basic cause of ringworm is dermatophyte infection, and the common dermatophyte is Trichophyton rubrum. When the dermatophytes come into contact with the surface layer of the skin, they will continue to grow and multiply by adhering, customizing, and penetrating the cells of the stratum corneum, affecting the proliferation of the skin cells, and ultimately leading to the occurrence and development of the disease. 2. Triggering factors: If there is a fungal infection such as ringworm or onychomycosis in itself, the symptoms of self-infection are likely to appear. Close contact with infected people, such as sharing clothes, bedding or towels, may also lead to infection. People with diabetes and chronic wasting disease can develop ringworm due to low immunity. If tinea corporis is diagnosed, early and standardized treatment is recommended to minimize the adverse effects of the disease.