What are fungal nail infections (onychomycosis)?

Dr. Mehmet Oz, MD
Cardiology (Cardiovascular Disease)

You (and those around you) can tell if you've developed a nail fungus if your nails are thickened, brittle, distorted, flat, and have turned yellow (without the benefit of yellow polish), a side effect of debris building up under the nails. Nail fungus - again, signaled by ugly, thickened, yellow nails - is more common in older adults than younger ones, because nails grow more slowly and thicken with aging - making them more susceptible to infection. Nail fungus usually begins as a white or yellow spot under the tip of your fingernail or toenail, and can be caused by three different fungi. Toenails are more susceptible to fungal infection because they spend most of their time in dark, damp shoes and socks; fingernails are dry and are exposed to UV light, which kills fungi.
Fungus is made up of microscopic organisms that can invade through invisible cuts in your skin or through a small separation between your nail and the nail bed or after an injury (like dropping a hammer on your toes). As the fungus spreads deeper into the nail, it may cause the nail to discolor, thicken, and develop crumbling edges that are sometimes as painful as they are ugly. Fungus usually grows when your nails are continually exposed to moist environments, like sweaty shoes or shower floors (by the way, it's not the same as athlete's foot, which affects the skin).

You: Being Beautiful - The Owner's Manual to Inner and Outer Beauty

More About this Book

You: Being Beautiful - The Owner's Manual to Inner and Outer Beauty

Most people think that beauty revolves around such things as lipstick, sweet eyes, or skinny jeans -- all those things that we can see (and obsess over) in the mirror. But the fact is that beauty...

Continue Learning about Fungal Infections

What is mycotoxicosis?
Lawrence T. Chiaramonte, MDLawrence T. Chiaramonte, MD
Molds such as Stachybotrys chartarum, Fusarium, and Trichoderma can produce very toxic compounds, wh...
More Answers
What is fungus?
A fungus is a type of organism that lives in soil, water, on plants and in the air. Mold is a common...
More Answers
What is bronchopulmonary aspergillosis?
The aspergillus fungus can grow on dead leaves or in bird droppings, stored grain, compost stacks or...
More Answers
How do I manage my fungal infections on a daily basis?
Diana MeeksDiana Meeks
You can manage your fungal infections on a daily basis by following the indications of your doctor r...
More Answers

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.