Overview of Fungal Infections
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 athlete's 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.
Fungi are a unique group of organisms that have some plantlike characteristics. Examples of fungi include mushrooms, mold, and yeast. Fungi differ from plants, however, in two major ways: (1) their cell walls are made of chitin, rather than cellulose, and (2) they lack the ability to make their own food by photosynthesis; thus they grow directly on their food source. This food source can be the human skin.
Some fungi are simple one-celled organisms. Others are relatively complex, exhibiting specialized cell functions. They grow in soil, on living and dead plants and trees, as well as on animals and humans. The reproductive cell, or spore, of a fungus can be spread by direct contact, air, and water.