Usually it is that serious. Most people treat their itchy toes before it spreads. Sometimes the infection spreads to the skin on other parts of the body. Athlete's foot are the moist and airless parts of the skin such as the groin. However, other germs (bacteria) may enter through the cracked skin of untreated athlete's foot. This can occasionally cause more serious infections of the foot or leg. So to keep your training or exercise fun it is important to treat them properly