Having gray nails on your hands, also known as onychomycosis, can be contagious to others. Tinea cruris is a disease caused by dermatophyte infection, which is contagious and can be transmitted through direct contact and indirect contact. Tinea cruris is a disease caused by ringworm infection, which is contagious through direct contact and indirect contact. Tinea cruris spreads directly from tinea cruris, and if the patient is in close contact with the fungus, the fungus may be infected through close contact, and the supplies contaminated by the patient may cause cross-infection, and a normal person who comes into contact with contaminated items from the patient may be infected as well. Suffering from nail fungus should be used individually, seek medical advice as soon as possible, and follow the doctor’s instructions for standardized treatment.