What’s the connection between fungus spores and nail fungus? Fungi that are actively growing will eventually produce spores – tiny reproductive stages that break away from the plant and spread to new places on air currents, in water, and on living things that move about. Most people have seen fungal spores: perhaps you’ve seen a green dusty powder inside the bag of a loaf of bread that’s gone moldy, or noticed that portobello mushrooms leave a black coating on your cutting board. These substances are actually large numbers of spores (a single spore is microscopic so you can’t see it – by the time they become visible there are millions.)
It’s important to understand that most fungi produce spores of one find or another – infectious fungal spores, that is, those that can cause infection in people, only come from a few species. Portobello mushroom spores, and those of most other environmental species will not hurt you (though it’s probably not a good idea to casually inhale spores of any fungus, for various reasons). There is only a connection between fungus spores and nail fungus infection when the spores are from one of fungi that can grow in keratin, the protein that is common in nails, hair, and skin.
Infectious fungal spores are produced by fungi growing in infected toenails and fingernails. They are dispersed in the environment when bits of nail and skin flake off, on nail clippers and instruments used to trim and file nails, in nail clippings, in shoes and socks, in water, and when the afflicted person walks about with bare feet. When you realize that a small colony of fungus can produce millions of spores, it’s easier to understand how the infection can spread readily from one nail to another, on shared clothing and grooming instruments, and in public swimming areas. An infection produces fungus spores and nail fungus spreads.
Most cases of fungal nail infection are caused by a few species of dermatophytes – fungi that are adapted to utilize keratin as a nutrient source. They spread from person to person and from animal to person by means of fungus spores and nail fungus infection is not the only problem they cause: infections of the skin and hair are generally caused by the same species. A few environmental fungi, i.e. species that normally live in nature, deriving nutrients from decaying organic material, can also produce infectious fungal spores that can grow in nails, but not skin or hair. Fortunately, the species involved in any particular infection does not generally matter when it comes to treatment of onychomycosis.