Athlete's Foot

Causes
Athlete's foot is caused by a fungus that belongs to the family of fungi known as dermatophytes. These are yeast like substances, which are parasitic in nature.  

Dermatophytes are opportunistic, in that something has had to go wrong in the immune system and natural flora in the colon for them to attack the skin, scalp, groin area, toenails, fingernails, space between the toes and skin on the soles of the feet. 

Dermatophytes that cause athlete's foot thrive in moist, warm environments, such as shower floors, and tennis shoes. Athlete's foot is a highly contagious and has preference for the protected space between the toes but will also eat on the skin that makes up the sole of the feet. Athlete's foot starts out with sever itching and progresses to deep, painful cracks that can bleed. 

Treatment