I don't understand why people suggest others to "just use an OTC anti-fungal cream." There are different types of foot fungal infections and different types of OTC and prescription anti-fungal creams. It's not possible treat every fungal infection with the same type of cream. People have to first figure out the type of fungal infection they have and then find out which medicated cream is effective for it. It's a waste of time and money to try random creams from the pharmacy.
If it's athlete's foot, for example, a cream with the active ingredient clotrimazole or miconazole is needed. Terbinafine cream is usually used for nail fungal infections and the list continues.