Most people are familiar with infections and diseases caused by bacteria and viruses, but many are unaware that there is a whole set of disorders related to infections by fungi (singular: fungus). Many of these fungal infections affect the skin. Doctors give some fungal infections of the skin the general name “tinea.” Superficial fungal infections are found in the top layers of the skin and mucous membranes, the hair, and the nails. Examples of fungal infections of the skin and other external surfaces include athletes foot, jock itch, ringworm, and candida. These can affect the hair and nails as well. Deep fungal infections invade deeper layers of the skin and hair follicles and can spread to the blood or internal organs.