What causes these infections?
Fungus is in the same class of organisms as mushrooms, yeast and molds. They're basically organisms that grow on dead or dying tissue. The outer layer of our skin and our nails are dead tissue. In other words, they don't have blood flow to them, and they become hard and thickened and allow us to have kind of a water-proof surface. So when someone has a fungal infection, the fungus gets into those tissues and starts to grow.
Who is likely to have these infections?
Older individuals are more likely to have it. We're not sure why. It might be that their immune system is diminished, or just that they've had more trauma to their toenails over the years.
Because of the association with trauma, you also see fungal infections in individuals who are in sporting activities such as soccer or ballet because they frequently injure their toenails. They might get a blood clot underneath the nail and, over a prolonged period of time, the fungus can get underneath the toenails. The blood clot creates a nice environment for the fungus to set up shop because fungus likes areas that are warm and moist.
But fungal infections can occur in most anyone, and the incidence of fungal infection has been increasing over the last 100 years. It may be due to the spread of the fungus in communal locker rooms and spas and showers. It may even be because of its association with diabetes.
Why is diabetes a possible risk factor?
People with diabetes often have a poor blood supply to the extremities, therefore the foot is not as healthy and fungus can set up more easily. Maybe it's also that many people with diabetes have decreased sensation, so any trauma—which they may not notice—plays a role.
We also see an association between foot fungus and immune deficiency diseases such as HIV and AIDS.
What are the symptoms of a nail fungus?
It can start in several different ways. But usually it appears as a yellow, brownish discoloration of the toenail. It usually starts at the end of the toenail, then starts working its way back underneath. It makes the nail thick, yellow, crumbly. Sometimes you'll see yellow streaks coming into the toenail as the fungus progresses.
There are also some funguses that occur towards the surface of the nail. We call them superficial funguses, and they are caused by a different fungal organism. They would cause more of a whitish coloration.
What about the fungal infections of the feet?
It basically starts between the toes or on the bottom of the foot. It's a cracking, peeling, itching. Sometimes you'll see little bumps on the foot that look like they have small pus pockets that tend to itch and burn. They are oftentimes associated with an odor; the feet will smell pretty strong.
Can that infection lead to the nail infection?
That actually tends to be highly correlated. Someone with longstanding athlete's foot tends to have a higher incidence of nail fungus.
What are the topical medications for these infections?
There are a number of different topical antifungal medications that people can pick up either from the podiatrist or their pharmacy.
Some over-the-counter medications can work very well for athlete's foot. But the nail fungus tends to be more resistant to cure with most topical ointments and creams. The only one that's been approved by the Food and Drug Administration (FDA) for nail fungus is ciclopirox (Penlac), a nail polish-like material that is brushed on. You paint it on every day, strip it off every week. It tends to take around nine months to get significant results.
When would someone go on an oral medication?
A lot of people use the oral medications for treatment and they're the most effective. There are two FDA-approved antifungal pills, terbinafine (Lamisil) and itraconazole (Sporonox). You have to take medication for three months for a nail fungus, but shouldn't take it for more than six months.
If it's athelete's foot, I usually prescribe oral antifungals if the topical medications haven't worked, or if it's a really bad infection. Usually it only takes between two and four weeks of therapy to resolve athlete's foot.
Since there is a small chance that some people taking these medications will develop liver problems so it is important to weigh the risks and benefits with your doctor. I'll do liver function tests in someone who has taken oral antifungals for more than three months just to make sure there aren't any problems.
When might someone have the nail removed?
If the nail has been completely deformed or it is thickened or painful, it will sometimes be removed as part of the treatment. The podiatrist will take the toenail off, and then they will put the patient on an antifungal medication. The idea being that if you take away all of the old nail and then start off with a new bed that doesn't have all that fungus, a healthier new nail may come back in.
These procedures are usually done in the office under a local anesthesia where we just numb the toe. The nail is removed from the nail bed and then wrapped up. It usually takes about two weeks for that to grow back in.
Some people opt for permanent toenail removal, so that they never grow back a new toenail. In this procedure, we remove or kill the cells at the back of the nail that are attached to the bone covering. It takes a little longer to heal from this procedure.
The nail is permanently removed when you're concerned that the fungus will recur, or if the nail and skin underneath has been severely deformed and is causing a lot of pain.
Are there any consequences to not treating the infection?
Deformity of the nail and skin would be the main concern, and the fact that it might spread to the other toes. The infection may also cause the toenail to become so thickened that the pressure—a concern in people with diabetes who might have numbness from nerve damage—can cause an underlying ulceration of the toe and cause further problems.
Are there any repercussions if you don't treat athlete's foot?
You might also get a bacterial infection a crack or an injury between the toes allows for bacteria to set in. That may have to be treated with either oral or IV antibiotics, or surgery if the infection gets too deep.
Can the infection spread to other people?
It's thought that it can and that's why the public facilities like locker rooms and spas might be a source of spread. But there also has been some evidence, and I see this in my own practice, that there may be a family association with it. So if you see it in one member of the family, it's more likely to happen in other members of the family. Is it because they have a similar genetic makeup that makes them susceptible to fungal infections or is it just because they live together? We're not exactly sure.
Is it possible to get a fungal infection from a pedicure?
If someone has a pedicure from an establishment who does not clean the instruments from one person to another, a fungus could be spread.
How can someone try to prevent a fungal infection?
I get that a lot and I don't know if there is any way to do that. Keep your feet dry. Wear flip-flops or shower sandals in the locker room. Take good care of your toenails. Make sure that if you see signs—yellowing or thickening at the end of the toenail—you keep your toenails cared and trimmed properly.
At what point should someone see a podiatrist?
I think people should come in if they have any concerns about their feet, at least get their questions answered. It may not always be a fungal infection; it might be a bacterial infection or psoriasis. But a podiatrist would be the best person to be able to decide whether culture was necessary to figure out whether it is a fungal infection.
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