Various bugs including fungi and bacteria live quite harmlessly on your skin, on your nails, or in your mouth or in your vagina - all the time. However certain types of fungus can cause actual infections and make your skin itchy or sore. What effect the fungus has depends on the type of fungus and the bit of your body that is affected. Fungal infections particularly like to live in warm moist places around your body like between your toes, between your fingers, and in your groin. Fungal infections like the skin because they feed off "keratin" which is a protein which is in skin, hair and nails.