Fungal infections of the nails (technically known as onychomycosis or tinea unguim) are quite common, affecting up to 10% of adults in Western countries, and increasing to about 20% of older people. It is much more common to get fungal infections of the toenails than the fingernails (perhaps because feet often live in the dark, humid environment of shoes).
Fungal nail infections are most commonly caused by a class of fungi called dermatophytes, which can infect the skin as well as the nails. Some yeasts can also cause infections of the nails, and there may be infection by a combination of fungi, yeasts and bacteria. Sometimes the skin around the nail is involved. If you have a fungal nail infection then you almost certainly have the same fungus on your skin (even if you cannot see a problem with the skin).
Appearance and classification
The most common type of fungal nail infection starts at the ends or sides of the nail and spreads slowly towards the cuticle. The infected area may be white or yellow, and there may be a gap between the nail and the underlying toe (called onycholysis).
More rarely, the infection may start at the base of the nail. This is more commonly associated with underlying medical problems.
Sometimes only the surface of the nail is involved, especially in those who wear nail polish frequently.
Over time, the infected nail may become thickened, misshapen and flakey.
Causes and risk factors
In normal, healthy people, fungal infections of the nails are most commonly caused by a fungus that is caught from moist, wet areas. Communal showers, such as those at a gym or swimming pools, are common sources. Going to nail salons that inadequately sanitise instruments (such as clippers, filers, and foot tubs) in addition to living with family members who have fungal nails are also risk factors. Using nail polish, especially for extended periods of time, make the nails more susceptible to fungal infections. Athletes have been proven to be more susceptible to nail fungus. This is presumed to be due to the wearing of tight-fitting, sweaty shoes and associated with repetitive trauma to the toenails. Having athlete's foot makes it more likely that the fungus will infect your toenails. Repetitive trauma also weakens the nail, which makes the nail more susceptible to fungal infection.
Elderly people and people with certain underlying disease states are also at higher risk. These include anything that impairs your immune system, making you prone to getting infected with the fungus. For example, conditions such as diabetes, cancer, AIDS, psoriasis, or taking immunosuppressive medications such as steroids.
Are fungal nail infections contagious?
Fungal infections of the skin and nails are only slightly contagious, and so transmission from one person to another is unlikely, unless there is intimate contact or sharing of socks or footwear. Some people are more susceptible than others. For example, two people can share the same bed, but only one may develop a fungal infection, even though the other person is exposed to the fungi as well.
Fungal nail infections are either diagnosed clinically (which means by a health practitioner examining them and concluding that the appearance is most likely caused by a fungal infection), or by collecting samples of the nail and sending them to a pathology laboratory for confirmation. While this can give a definitive diagnosis, there are often false negatives (which means that there is a fungal infection, but the laboratory sample could not confirm it). Also, fungal nail infections are more likely to occur in nails which already have other problems, so there might be a fungal nail infection and another problem with the nails. Nails may look abnormal for several other reasons. For information on other causes of funny looking nails, see here.
Who should get treated?
Many people do not actively treat their fungal nail infections, even though they are unsightly. Reasons to treat them include:
- Concerns with the appearance of the nails.
- Pain or discomfort (sometimes worse when wearing shoes, or with certain activities, such as sports).
- Those who are at increased risk of getting other infections, or who have had infections or ulcers on their feet or legs in the past.
- Those with certain medical problems, including diabetes.
Successful treatment is not always guaranteed and sometimes a recurrence can occur. It can also take 12 months or longer for the nails to appear normal again even after successful treatment because the nails grow slowly. The new healthy nail takes time to replace the old fungal-looking nail. Whatever treatment option you choose, you will need to be patient!
Regularly keeping the nails properly trimmed and thinned (if necessary) makes them look and feel better and minimises the amount of fungus in the nails. It is highly recommended to do this whatever treatment is chosen.
Treatment options include:
- Oral medications
- The most commonly used oral medication in Australia is Terbinafine (e.g. Lamisil). Tablets are taken daily for up to 6 months. It is generally quite effective, but not always. You may need to have blood tests whilst taking this medication.
- Other oral medications less commonly used include Itraconazole (e.g. Sporanox), Fluconazole (e.g. Diflucan) and Griseofulvin (e.g. Grisovin)
- Topical medications
- Amorolfine lacquer (e.g. Loceryl) is applied regularly to the nail, which needs to be filed down first. It is quite effective, but relies on regular application. It is less effective if the nail infection goes all the way to the base of the nail.
- Ciclopirox (Rejuvenail). Another drugs which is applied to the nail.
- Terbinafine (e.g. Lamisil, Solveasy). Available in several formulations, including spray, cream etc. Great for treating fungal skin infections, but not very effective on nails as the only treatment method.
- Others. There are a number of antifungal products available from chemists. Most of these are not particularly effective for treating fungal nail infections.
- Oral medications
- Laser treatment
- A laser of a specific wavelength is used to penetrate the nail and kill the fungus. Laser fungal nail treatment is painless and convenient, and usually requires 2 to 4 treatments over several months.
- Surgical removal of the nail. This can be done when the nail has a fungal infection, or when it has been damaged by trauma or other infections. Further treatment with anti-fungal medications (either oral or topical) may be warranted in order to prevent recurrence.
- Other treatments
- Products such as Emtrix claim to help the nail look better as well as making the nail a difficult environment for the fungal infection to survive.
- Home Remedies. There are quite a few of these. Most have minimal scientific evidence to support their use.
- Vinegar is probably not helpful for most fungal infections, but may be helpful with yeast infections, especially of the skin.
- Oils, such as tea tree oil, essential oils, coconut oil and oil of cedar leaf.
- Bleach, Hydrogen Peroxide. These can cause skin irritation.
- Urea cream softens the nail, and makes it easy to trim and thin.
- Undecylenic acid, propylene glycol: these ingredients may be listed in some off-the-shelf treatments. They have anti-fungal properties, but may have difficulty in penetrating the nail, and can irritate the skin in some cases.
Prognosis (will it get better?)
Curing fungal nails can be difficult and treatment can take more than 12 months. Relapse and reinfection are common (40%-70% reinfection rate). Trying to remove or modify your risk factors, if possible, is essential to preventing reinfection. People who have medical illnesses that predispose them to fungal nails can have an even more difficult time eradicating the fungus.
Recurrence (will it come back?)
If you are predisposed to getting fungal nail infections or tinea, then it can come back. A recurrence after a previous treatment does not mean that the treatment failed; you can get another infection later on.
There are also ways to minimise the chance of reinfections. These include:
- Clean and dry your feet regularly.
- Keep your toenails properly trimmed. If you can't do this yourself, get your podiatrist to do it on a regular basis.
- Good hygiene with socks and footwear. Wear clean, dry socks and properly fitting shoes. If your washing machine has a hot wash option, then washing in water at least 60 degrees centigrade will kill most fungus. Using anti-fungal laundry additives such as Canesten laundry rinse may also help.
- Rotating shoes, so you don't wear the same pair every day. This allows them to air and dry out. You can also use portable UV light sanitisers and other methods to disinfect shoes.
- Don't wear shoes all the time. If you live in a warm climate then open shoes and bare feet from time to time helps. Get some air and light onto your feet!
- Athlete's foot (tinea) is caused by the same bug that causes fungal nail infections, and so can spread to the nails. If you have athlete's foot, then treat this with an appropriate anti-fungal cream containing Terbinafine (e.g. Lamisil, Solveasy).
- Don't wear nail polish continuously. Have a break from time to time.