Ringworm on the back of the neck in summer may be due to fungal infection caused by tinea corporis or lichen planus. 1. Tinea corporis: ringworm on the back of the neck may be tinea corporis, which is caused by infections such as red trichophyton and plaster-like trichophyton. It is caused by direct and indirect contact infection, and can also be formed through the spread of its own foot, hand and nail ringworm infection. The lesions begin as red papules, pimples or blisters. Then red patches with scales are formed. The border is clear, and the edges keep spreading outward. 2. Tinea pedis: Malassezia is a common host bacterium in human body. The main pathogenic bacteria causing lichen planus is Malassezia globosa, which is related to high temperature and humidity, fatty and sweaty, chronic diseases and so on. Skin lesions are initially pore-centered, well-bordered dotted rash, neighboring lesions can be fused with each other to form large irregular patches, and the surface is covered with furfuraceous scales. If you have ringworm on the back of your neck in summer, you need to seek medical attention as soon as possible and actively treat it to avoid the spread of the lesions.