Tinea pedis is the common name for tinea pedis and tinea cruris is the common name for tinea cruris, both of which are caused by fungal infections and require antifungal treatment. Tinea pedis is a fungal infection of the superficial skin of the feet, and onychomycosis is a nail lesion caused by a fungal invasion of the nail plate and subnail tissue. Because fungal infections can be transmitted, both diseases can coexist and treatment is antifungal. Tinea pedis can be treated with topical medications such as econazole and ketoconazole. Since it is difficult for drugs to penetrate the nail plate, systemic therapy, such as oral itraconazole and terbinafine, is mostly used in the treatment of onychomycosis. The combination of topical and oral medications usually results in better outcomes. There are individual differences in the choice and dosage of specific medications, so it is recommended to follow the doctor’s instructions.