Nail
Fungus: Symptoms and Treatment
Nail
fungus, also medically known as onychomycosis, is a chronic fungal infection of
the fingernails and/or toenails by dermatophytes, also known as ringworm,
yeasts and molds, leading to gradual destruction of the nail plate. It is more likely to affect toenails, particularly the first toenail, than fingernails, according
to the National Institutes of Health (NIH).
Fungal
infection of the nail is very common. About half of the population is affected
with nail fungus by the time they reach 70 years of age, said Dr. Raza Aly,
professor emeritus of dermatology at the University of California, San
Francisco Medical Center. Fungus is responsible for 50 percent of all nail
disease, according to the U.S. National Library of Medicine.
Symptoms
An infected nail often will have unsightly
white/yellow or orange/brown patches or streaks. It can also turn thicker, crumbly, ragged or dull, according to the Mayo
Clinic. In some cases, the nail will emit a slightly foul odor and it may
separate from the nail bed, a process known as onycholysis.
"More commonly, people don't like the
way it looks," said Dr. Bernard Cohen, a professor of pediatrics and
dermatology at Johns Hopkins Children's Center in Baltimore, Maryland.
"[But] the nails can become friable; they break up and fall off." An
infected nail can also thicken, making it difficult to clip, and cause
discomfort if it catches on clothes, for instance.
Nail fungus typically begins with a fungal
infection of the skin, such as athlete's foot. Once the skin is treated, however, the nails
may act as a reservoir for reinfection that can spread the fungus to other
parts of the body or to other people, Cohen told Live Science.
In some cases, people may have a genetic
susceptibility to nail fungus, reported a 1996 study in the Journal
of the American Academy of Dermatology.
Diagnosis & tests
Although half of all nail disorders can be
categorized as onychomycosis, it is not always possible to identify the disease
accurately by just looking at the symptoms, according to a treatment guideline
commissioned for the British Association of Dermatologists. Other conditions,
such as psoriasis, can result in similar nail abnormalities as well.
Once the above symptoms are observed, lab
tests consist of microscopy to visualize fungal elements and a mycological
culture to help identify the species of microbes involved will provide a more
definitive diagnosis. Since onychomycosis is primarily a disease of the nail
bed rather than of the nail plate, skin debris and samples taken from the spot
closest to the infection is likely to yield the best results, according to the
British guidelines.
Treatment & medication
Onychomycosis is not self-healing and may be
a source of more widespread fungal lesions on the skin, or vice versa.
Additionally, a person cannot cure an infection by covering it with nail polish
or fake nails, according to the American Academy of Dermatology. Cleaning the feet every day,
filing off the white areas and treating the feet with over-the-counter
anti-fungal creams can help with mild infections. Using a mentholated rubbing
cream, such as Vicks VapoRub, has been found to be a useful at-home treatment
as well. A 2011 study published in the Journal
of the American Board of Family Medicine found that 15 of the 18 participants
showed improvement after using a mentholated rub on their infected toes. While
this small of a study sampling is inconclusive, it maybe something to try for
those with mild nail fungus.
If the nail is deformed, discolored or
thickening, it is time to visit a medical professional, according to the American Podiatric Medical Association. There are both topical
and oral treatments are available to help the condition.
"Oral antifungal therapy is preferred
because of its ability to penetrate the nail bed and nail plate and thus
sustain effectiveness," Aly said. However, because oral medication
includes side effects such as potential liver damage, doctors and patients
typically prefer topical creams, even though they are typically less effective
because of poor penetration into the nail, he added.
Oral antifungal medications such as
terbinafine (commonly marketed under the trade name Lamisil), itraconazole
(Sporanox) and fluconazole (Diflucan or Trican) encourage the growth of new,
non-infected nail, while slowly cycling out the infected portion of the nail,
according to the Mayo Clinic. The medication is usually taken for six to 12
weeks, but a toenail may take up to 78 weeks to grow fully, and preventative
measures should be taken during that gap to avoid recurrent infection.
The U.S. Food and Drug Administration (FDA)
approved two other treatments in 2014. Efinaconazole (Jublia) is a topical
cream that targets mild to moderate cases of onychomycosis, Aly said. About 17
percent of people taking it daily for a year had a complete cure rate, meaning
that there was no fungus left on the nail and the nail looked normal, reported
a 2013 study in the Journal
of Drugs in Dermatology.
The second treatment, tavaborole (Kerydin),
is also a topical cream that has a similar complete cure rate after a year of
use, Aly said. Both of these new topical medications are more effective than
the FDA-approved nail lacquer Penlac, which has a complete cure rate of about 5
percent to 8 percent, he said.
Nail removal may be an option if the
infection is severe or extremely painful. This can typically be performed
in-office. The new nail may take up to a year to fully grow in, according to
the Mayo Clinic.
Another treatment option is laser and
light-based therapies. The therapy may be combined with other treatments, such
as carbon-dioxide laser therapy combined with antifungal nail cream.
Successful eradication of the fungus may
still leave the nail looking permanently abnormal because of trauma to the nail
bed and nail plate by the disease, according to a 2007 article published in the
Journal of the American Academy of Dermatology. Therefore, a cure should be
based on lab tests and not on visual appearance.
Prevention
The fungi that cause onychomycosis thrive in
warm, moist areas, according to the NIH.
"That stuff is everywhere," Cohen
said. "It lives in your shoes, it lives in your socks, it lives in your
bathroom. They're resistant to freezing and heating. Even if you can get them
off your skin, they're just everywhere. The risk of re-exposure is quite
high."
General hygiene practices such as keeping
all nails short, dry and clean will help decrease the risk of infection. One
should avoid going barefoot in public places and choose a reputable salon that
properly cleans and disinfects its manicure and pedicure instruments.
Even going barefoot in a locker room or
public shower can lead to contracting athlete's foot, which is easily
transmitted in moist environments, said Dr. Andrew Shapiro, a podiatrist in
private practice in Valley Stream, New York, and spokesman for the American
Podiatric Medical Association. [Barefoot in the summer: The Pleasures and Perils of Going Shoeless]
Wearing breathable socks and shoes may also
help prevent fungal infections, Cohen said.
Sometimes, patients will have onychomycosis in
just one nail, often because a trauma such as dropping a book on a toe, which
may make it easier for a fungal infection to take hold, Aly added. Because the
fungus can spread to other nails, he encouraged people to clean their nail
clippers. People who pursue treatment for their feet should also buy new socks
and shoes.
"Some of those fungal spores, they
remain viable for months in those shoes," Aly said.
