The human body contains a vast number of different micro-organisms, including fungi, both on the inside and on the outside. Some of these micro-organisms are beneficial. Others have no effect until either there is a change in their nature or there is a decrease in the body's resistance to them. This allows one type to grow excessively and leads to an infection - a fungal infection of the skin.

In principle, Candida albicans can infect all areas of the skin as well as the mucous membranes but it prefers warm moist places.

Infections by Candida albicans, especially the variants that are found in the mucous membranes or the genitals, are contagious. They can be spread from person to person by direct contact, by sexual contact and indirectly by damp towels or flannels.