Tinea cruris, otherwise known as jock itch, is a fungal infection that can cause a red and itchy rash in warm and moist areas of the body, such as the groin. To prevent jock itch, the Mayo Clinic recommends the following: keep your groin area dry after exercise or showering; wear clean clothes that don’t chafe skin in the groin area; don’t share personal items (clothes or towels); and treat or prevent athlete’s foot because it can spread to the groin. Mayo Clinic, July 2021