The medical name for athlete’s foot fungus caused by a fungus is tinea pedis. Red or black nails due to a hematoma, or blood under the nail, usually from trauma (like whacking yourself on the thumb with a hammer). The affected nail will become discolored (yellow or brown) and will become very thick and overgrown.
Follow all, or practically all, of these suggestions if you wish to get rid of this annoying condition. Commonly used anti-dermatophytic agents that are also active against the yeasts include the imidazoles, and the hydroxypyridones, which are also effective against most of the moulds.