Jock Itch (tinea cruris) is a form of ringworm. Ringworm is not a worm at all. It is a fungal infection of the outer layers of skin, hair, or nails. Fungi (plural of fungus) are present everywhere in our environment. Most ringworm infections of the skin, such as jock itch, can be treated at home with antifungal creams and powders you buy without a prescription, such as Pro-Ex. But have your doctor look at any infection that does not go away, is severe, or comes back.Expiration05/01/2020