"In general, humans have a high level of innate immunity to fungi and most of the infections they cause are mild and self-limiting. This resistance is due to:
Fatty acid content of the skin
pH of the skin, mucosal surfaces and body fluids
Epithelial turnover
Normal flora
Transferrin
Cilia of respiratory tract
When fungi do pass the resistance barriers of the human body and establish infections, the infections are classified according to the tissue levels initially colonized."