I tired to answer this for you in chat. But now I get to give a much better explanation 🙂
Athlete’s foot is a fungal infection of the skin on the feet. It is very common – up to one in four people have athlete’s foot. Harmless bacteria and fungi live naturally on your skin, but if these organisms multiply, your skin can become infected.
A group of fungi called dermatophytes is responsible for athlete’s foot. Dermatophytes live in and feed off dead skin tissue.
It is more common in people who sweat more, or who wear shoes and socks which make their feet more sweaty. Athlete’s foot can also be passed on from person to person. For example, this may occur in communal showers used by athletes or swimmers.
To prevent it:
Wash your feet regularly using soap and water.
After washing your feet, dry them thoroughly, paying particular attention to the areas between your toes.
Wear clean cotton socks.
Change your socks and shoes regularly to help keep your feet dry, particularly after exercising.
Don’t share towels and wash your towels regularly.