Onychomycosis: fungal nail infection
Onychomycosis (tinea unguium) is a fungal infection of the
matrix or plate. Toenails are affected more often than fingernails.
Onychomycosis accounts for one third of integumentary fungal infections and one
half of all .
According to the November 2000 issue of the Journal of the American Academy
of Dermatology, onychomycosis is also the most common nail disorder among people
, representing about 30 percent of cutaneous fungal infections.
In the most common form of fungal nail infections, fungus grows under the
growing portion of the nail and spreads up the finger (proximally) along the
nail bed and the grooves on the sides of the nails.
The primary fungi that cause onychomycosis are trichophyton rubrum and
trichophyton mentagrophytes. They are dermatophytes (fungi that infect
, and nails) and
feed on keratinized (nail) tissue. The infections they cause are normally
confined to the nails, but occasionally spread to the surrounding skin.
Another type of onychomycosis is caused by yeast (candida albicans or candida
parapsilosis). These infections are less common and produce similar symptoms.
infections are caused by bacteria such as staphylococcus, streptococcus, and
pseudomonas. In most cases, paronychia infections can be differentiated from
onychomycosis by the inflammation they cause to the skin adjacent to the nail
In general, toenails are most commonly affected with fungal nail
infection. If the fingernails are affected, the toenails are usually affected
as well. Nails often become thicker and lift from the nail bed (onycholysis)
starting at the growing portion of the nail. You might then see debris under
the nails and discoloration of the affected area.
In some forms of fungal nail infection, you might see black or white,
powdery discoloration on the surface of the nail plate.
In some forms of fungal nail infection, you might see these abnormal
changes farther up the finger (proximally), where the nail originates.
Fungal nail infection may occur in people with
(tinea pedis) and/or oozing infection (paronychia), caused by
inflammation and infection with yeast and/or bacteria in the region where the
skin of the finger meets the origin of the nail.
In fungal nail infection, one, a few, or all nails may be affected.
Treatment Options for Onychomycosis
Onychomycosis is difficult to treat because nails grow slowly and receive
very little blood supply. However, there have been recent advances in treatment
options, including oral and topical medications.
Onychomycosis can be a serious ailment, but some simple and effective
treatments are available.
Having a healthcare professional regularly trim the nails and file down
the nail plate with a surgical burr—a procedure called debridement—tends to
reduce pain and fungal load, prevent ulceration and at least temporarily
improve the nail's appearance. This procedure can also be performed in
conjunction with topical and oral antifungal therapies.
Topical antifungals have traditionally been unsuccessful in treating
onychomycosis. However, using the antifungal lacquer ciclopirox for up to one
year can often help diminish the infection.
The oral antifungal treatment Lamisil (terbinafine hydrochloride tablets)
has a cure rate of about 70 percent, with few side effects and minimal drug
interactions. With oral therapies, the patient's liver function must be
monitored for any rarely occurring hepatic complications.
If you do not want to try to cure the condition you can control
onychomycosis and improve the appearance of the nails by brushing on FDA
approved undecylenic acid.
Removal of the nail will not get rid of onychomycosis. When the new nail
grows in, it almost always becomes re-infected.
commonly develop onychomycosis because blood circulation is poor in the
extremities, and the body's ability to fight infections is compromised. Small
cuts, infections, and foot injuries can have serious consequences for diabetics.
Recent studies have shown a higher rate of amputation in diabetics with
onychomycosis compared to those without the infection. It is important to
inspect the feet closely each day and work with a physician on a program of
thorough foot care.
Fungal nail infection does not always require treatment, but see your doctor
for any nail disorder. Diabetics with foot problems should be evaluated because
of the possible risk for developing foot ulcers. Your doctor may perform
testing, such as scraping a nail to examine for fungi or clipping a nail to look
for bacterial or fungal growth (culture) or to obtain a special stain to look
for fungi under a microscope.
The first line of defense against onychomycosis is good hygiene. Preventing
onychomycosis is the best option, but quick and effective treatment is available
if all else fails.