Fungus That Infects Nails

A species of fungus that infects nails is called a dermatophyte—literally meaning a “skin plant.” The reference to skin results from the fact that the same types of fungi can also invade skin, deriving their nutrients from the same protein that is abundant in nails: keratin. Keratin is a hard substance that is found in hair, the outer layers of skin, toe- and fingernails, animal horns, hoofs and claws. Dermatophytes can grow in all of these tissues and they are amongst the very few fungi that can.

Known dermatophyte facts tell us that even though these fungi often become established on nonliving materials such as nails and dead skin cells, they usually cannot spread further because the immune system of a live animal keeps them at bay. (The vast majority of fungi live on dead organic material such as leaves, decomposing bodies of animals, animal excrement etc. and help to break it down). Nails and hair, and even the outermost layers of our skin lack a blood supply and other body fluids that carry immune cells and molecules, but wherever such protective mechanisms are active, the fungus that affects nails can’t go. In certain rare instances, a dermatophyte may set up an infection in living tissue.

A dermatophyte fungus that infects nails usually belongs to one of three groups or genera of fungi: trichophyton (the most common in most places), microsporum, and epidermophyton. Each of these groups contains a number of species, some of which cause infections in humans while some do not. Thus, scientific knowledge about these fungi is complicated and the medical professional seeing patients with possible fungal infections must know their dermatophyte facts.

To aid in the identification of fungus that infects nails, medical laboratories have special media used to grow the fungus and specific tests to help determine which genus and species it belongs to. Individuals who suspect they have a fungal nail infection should consult their doctor or dermatologist and have nail shavings submitted to the laboratory for culture and identification. Even people who think they know their dermatophyte facts can be mislead by look-alike infections and fungus species that resemble dermatophytes but are actually harmless environmental species.

Fungus that infects nails is very common especially in older people. Any nail abnormality, however, should be assessed by a competent medical professional to determine whether fungus is the cause. Other conditions, some of them serious, can look very similar.