There are three kinds of fungus that can cause skin disease within humans plus animals. These kind of labels are known as Dermatophytes. This type of fungus can create infections on the nails, hair and skin because of the material called keratinized that contributes to the fungus.

The factors that act as a virulence include elastase, proteinases and the keratinases. These factors are usually restricted and can only be on the layer that is a cornified nonliving layer by the epidermis. The most popular infections that can happen from Dermatophytes include tinea or ringworm. The infections related to the fingernail and toenail are called onychomycosis. Dermatophytes almost always invade the outer layer part of the skin and not the tissues that are living. Sometimes there are organsims that might go into the tissues that are subcutaneous. When that happens it results with the development known as kerion.