Fungal Nails

  • Medical Author:
    Kyoung Min Han, DPM, AACFAS

    Dr. Kyoung Min Han is a podiatrist (foot and ankle specialist) practicing in Southern California. Dr. Han completed her undergraduate education at the University of California, San Diego, and went on to the New York College of Podiatric Medicine to pursue her medical training. She returned to her native Southern California to complete a three-year foot and ankle surgical residency, followed by subspecialty training in a sports medicine fellowship.

  • Medical Editor: Melissa Conrad Stöppler, MD
    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

A woman holds her feet and toes.

Introduction to fungal nails (onychomycosis, tinea unguium)

Many changes in fingernails or toenails may cause people to think they have a fungal infection of the nails, medically known as onychomycosis or tinea unguium.

Fungal infection of the nails sometimes makes the condition sound contagious or related to poor hygiene. In fact, up to 10% of all adults in Western countries have fungal infection of the nails. This percentage increases to 20% of adults who are age 60 or older. Toenail fungus is much more common than fingernail fungus.

In reality, abnormal-looking nails may be caused by a number of conditions including, but not limited to, fungal infection. There are many other reasons why your nails may look different.

Quick GuideNail Color and Texture: What Nails Say About Your Health

Nail Color and Texture: What Nails Say About Your Health

Nail Fungus Treatment

Onychomycosis is a fungal infection usually caused by a special type of fungus known as a dermatophyte. Since most of these infections are relatively superficial, it would seem that topical treatments ought to work well. This is not the case because the nail unit is relatively impenetrable.

Picture of Fungal Nails
Examples of conditions that are often mistaken for fungal nails include yellow nails (onycholysis), hematoma, green nails (caused by Pseudomonas bacteria), pitted nails (usually associated with psoriasis), nail infection (paronychia), and previous injury (trauma).

What other conditions can be mistaken for fungal nails?

Here are some other conditions you may have instead of fungal nails:

  1. Lines and ridges: These are common and may be considered normal. They may worsen during pregnancy. A large groove down the center of the nail can be caused by nail biting. Some people may develop these changes following chemotherapy.
  2. Senile nails: As you age, the nails become brittle and develop ridges and separation of the nail layers at the end of the nail. To avoid this, try to clean solutions and don't soak the nails in water.
  3. Whitish or yellowish nails can occur due to onycholysis. This means separation of the nail from the nail bed. The color you see is air beneath the nail. The treatment is to trim the nail short, don't clean under it, polish if you want to hide the color, and wait two to three months. Persistent onycholysis can make the nails susceptible to fungal infection.
  4. Red or black nails due to a hematoma, or blood under the nail, usually occur from trauma (like whacking yourself on the thumb with a hammer). The discolored area will grow out with the nail and be trimmed off as you trim your nails. If you have a black spot under your nail that was not caused by trauma, you may want to see a dermatologist or a podiatrist if it involves a toenail to make sure it is not melanoma (a type of skin cancer associated with pigmented cells). A simple biopsy can rule out malignancy (cancer).
  5. Green nails can be caused by Pseudomonas bacteria, which grow under a nail that has partially separated from the nail bed. This infection may cause a foul odor of the nails. The treatment is to trim the nail short every four weeks, don't clean it, polish if you want to hide the color, and wait two to three months. It is also advised to avoid soaking the nail in any sort of water (even if inside gloves) and to thoroughly dry the nail after bathing. If the problem continues, there are prescription treatments that your doctor may try.
  6. Pitted nails may be associated with psoriasis or other skin problems that affect the nail matrix, the area under the skin just behind the nail. This is the area from which the nail grows. Nails affected by psoriasis can also be tan in color.
  7. Swelling and redness of the skin around the nail is called paronychia. This is an infection of the skin at the bottom of the nail (cuticle). If the infection is acute (has a rapid onset), it is usually caused by bacteria. It may respond to warm soaks but will often need to be drained by a doctor. A chronic paronychia occurs when a cuticle becomes inflamed or irritated over time. Sometimes, yeast will take advantage of the damaged skin and infect the area as well. Therapy begins with keeping the skin dry and out of water. If the problem continues, a physician should be consulted. Antibiotics are not often used but may be necessary in severe infection.
  8. Chronic nail trauma, such as repeatedly starting and stopping, kicking, and other athletic endeavors, can cause damage to the nails that can look a lot like fungal nails. This sort of repetitive trauma can also occur with certain types of employment or wearing tight-fitting shoes. Some traumas may cause permanent changes that may mimic the appearance of fungal nails.
Microconidia of the fungus Trichophyton, which inhabit the soil and can lead to fungal infections of the skin, hair, or nails.

What causes fungal nails, and what are some of the risk factors?

In normal, healthy people, fungal infections of the nails are most commonly caused by 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 use inadequate sanitization of instruments (such as clippers, filers, and foot tubs) in addition to living with family members who have fungal nails are also risk factors. 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 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 can make you prone to getting infected with the fungus. These include conditions such as AIDS, diabetes, cancer, psoriasis, or taking any immunosuppressive medications like steroids.

Are fungal nails contagious?

While the fungus must be obtained from someplace, it is not highly contagious. Nail fungus is so common that finding more than one person in a household who has it is hardly more than a coincidence. It can be transmitted from person to person but only with constant intimate contact.

Toenail fungus
Examples of distal subungual onychomycosis, proximal subungual onychomycosis, and candidal onychomycosis.

What are fungal nail symptoms and signs?

Although fungal nails are usually cosmetic concerns, some patients do experience pain and discomfort. These symptoms may be exacerbated by footwear, activity, and improper trimming of the nails.

There are many species of fungi that can affect nails. By far the most common, however, is called Trichophyton rubrum (T. rubrum). This type of fungus has a tendency to infect the skin (known as a dermatophyte) and manifests in the following specific ways.

  • Starts at the ends of the nails and raises the nail up: This is called "distal subungual onychomycosis." It is the most common type of fungal infection of the nails in both adults and children (90% of cases). It is more common in the toes than the fingers, and the great toe is usually the first one to be affected. Risk factors include older age, swimming, athlete's foot, psoriasis, diabetes, family members with the infection, or a suppressed immune system. It usually starts as a discolored area at a corner of the big toe and slowly spreads toward the cuticle. Eventually, the toenails will become thickened and flaky. Sometimes, you can also see signs of athlete's foot in between the toes or skin peeling on the sole of the foot. It is often accompanied by onycholysis. The most common cause is T. rubrum.
  • Starts at the base of the nail and raises the nail up: This is called "proximal subungual onychomycosis." This is the least common type of fungal nail (about 3% of cases). It is similar to the distal type, but it starts at the cuticle (base of the nail) and slowly spreads toward the nail tip. This type almost always occurs in people with a damaged immune system. It is rare to see debris under the tip of the nail with this condition, unlike distal subungual onychomycosis. The most common cause is T. rubrum and non-dermatophyte molds.
  • Yeast onychomycosis: This type is caused by a yeast called Candida and not by the Trichophyton fungus named above. It is more common in fingernails and is a common cause of fungal fingernails. Patients may have associated paronychia (infection of the cuticle). Candida can cause yellow, brown, white, or thickened nails. Some people who have this infection also have yeast in their mouth or have a chronic paronychia (see above) that is also infected with yeast.
  • White superficial onychomycosis: In this nail condition, a doctor can often scrape off a white powdery material on the top of the nail plate. This condition is most common in tropical environments and is caused by a fungus known and Trichophyton mentagrophytes.
A doctor examines a patient's toenails.

What tests do health-care professionals use to diagnose fungal nails?

Physical exam alone has been shown to be an unreliable method of diagnosing fungal nails. There are many conditions that can make nails look damaged, so even doctors have a difficult time. In fact, studies have found that only about 50%-60% of cases of abnormal nail appearance were caused by fungus. Therefore, laboratory testing is almost always indicated. Some insurance companies may even ask for a laboratory test confirmation of the diagnosis in order for antifungal medicine to be covered. A nail sample is obtained either by clipping the toenail or by drilling a hole in the nail. That piece of nail is sent to a lab where it can by stained, cultured, or tested by PCR (to identify the genetic material of the organisms) to identify the presence of fungus. Staining and culturing can take up to six weeks to get a result, but PCR to identify the fungal genetic material, if available, can be done in about one day. However, this test is not widely used due to its high cost. If a negative biopsy result is accompanied by high clinical suspicion, such as nails that are ragged, discolored, thickened, and crumbly, it warrants a repeat test due to the prevalence of false-negative results in these tests.

Most of the medications used to treat nail fungus have side effects, so you want to make sure of what you are treating.

Who should be treated for fungal nails?

Medical treatment of onychomycosis is suggested in patients who are experiencing pain and discomfort due to the nail changes. Patients with higher risk factors for infections such as diabetes and a previous history of cellulitis (infection of the soft tissue) near the affected nails may also benefit from treatment. Poor cosmetic appearance is another reason for medical treatment.

What specialists treat nail fungus?

There are several doctors who can provide nail fungus treatment. Your primary care provider, a dermatologist, or a podiatrist can treat nail fungus. Any one of these doctors can provide proper diagnosis and prescribe medications specific to fungal infection. A podiatrist or dermatologist may shave the top layer of the nail off or even remove part of the nail.

A person trims their toenails.

What is the treatment for fungal nails?

Keeping nails trimmed and filed can help to reduce the amount of fungus in the nails and is highly recommended. This also provides pain relief when thickened nails cause pressure-related pain.

Creams and other topical medications have traditionally been less effective against nail fungus than oral medications. This is because nails are too hard for external applications to penetrate. It is also cumbersome to adhere to topical medication regimens. Oftentimes, these medications require daily applications for a period of time up to one year to see results. One of the major advantages of topical treatment is the minimal risk for serious side effects and drug interactions compared to oral therapy.

Prescription topical medications for fungal nails include the following:

Ciclopirox (Penlac) topical solution 8% is a medical nail lacquer that has been approved to treat finger or toenail fungus that does not involve the white portion of the nail (lunula) in people with normal immune systems. It only works about 7% of the time. The medication is applied to affected nails once daily for up to one year. The lacquer must be wiped clean with alcohol once a week. There is some evidence that using an antifungal nail lacquer containing amorolfine can prevent reinfection after a cure, with a success rate of about 70%. However, this drug is currently unavailable in the United States.

Efinaconazole (Jublia) is a medication that was approved in 2014. It is a topical (applied to the skin) antifungal used for the local treatment of toenail fungus due to two most common fungal species affecting nails (Trichophyton rubrum and Trichophyton mentagrophytes). Once-daily application is required for 48 weeks. The most common side effects of Jublia are ingrown toenails and application site dermatitis and pain.

Tavaborole (Kerydin) is another new medication that is indicated for onychomycosis of the toenails. This medicine has the same indication as efinaconazole. It also requires application once daily for 48 weeks. Common side effects of Kerydin are similar to those of Jublia.

A woman takes antifungal nail medication.

What is the treatment for fungal nails? (Continued)

Oral antifungal therapy works about 50%-75% of the time, depending on the medication. It can take nine to 12 months to see if it has worked or not, because that is how long it takes for the nail to grow out. Even when therapy works, the fungus may come back about 20%-50% of the time. Currently, an oral antifungal therapy is considered the best treatment for toenail fungus because of higher cure rates and shorter treatment duration compared to topical therapy.

Prescription oral medications that are effective against nail fungus include the following:

  • Griseofulvin (Fulvicin, Grifulvin, Gris-Peg): This drug has been the mainstay of oral antifungal therapy for many years. Although this drug is safe, it is not very effective against toenail fungus. Disappointing long-term results have been reported. Newer agents have largely supplanted it.
  • Terbinafine (Lamisil): This drug is taken daily for 12 weeks for toenails and six weeks for fingernails. The drug is safe, effective, and produces few side effects. However, it must be used with caution in patients with liver disease. This medication is also affordable.
  • Itraconazole (Sporanox): This is often prescribed in "pulse doses" -- one week per month for two or three months. It can interact with some commonly used drugs such as the antibiotic erythromycin or certain asthma medications. It is considered the treatment of choice for onychomycosis caused by Candida yeast and non-dermatophytic molds.
  • Fluconazole (Diflucan): This drug may be given once a week for several months. The dosing of this drug may need to be modified if the patient has impaired kidney function or is taking it simultaneously with certain other medications. It is not as effective as Lamisil or Sporanox and should be used cautiously in patients with liver disease.
  • A doctor will determine whether a simple blood test is needed to check for liver disease.

There are several innovative treatments that are still being tested:

  • Laser therapy or photodynamic therapy uses application of light-activated agents onto the nail followed by shining light of a proper wavelength on the nail.
  • Use of electrical current to help absorption of topical antifungal medications into the nail: This is also called iontophoresis.
  • Use of a special nail lacquer that changes the micro-climate of the nail to make it inhospitable for the fungus to grow: If this works, it may be an inexpensive way to treat this problem in the future.

One way to definitively get rid of toenail fungus is by surgery. Surgical treatment of onychomycosis involves nail removal. However, this often only provides temporary relief, and recurrence is common unless additional antifungal medication (oral or topical) is simultaneously used. However, surgical removal may be warranted when the affected nail is associated with other factors such as trauma and or infection.

Are there home remedies for toenail fungus?

The Internet is filled with anecdotal information on how to cure toenail fungus using home remedies. Vinegar is a commonly recommended home remedy. Some people apply various oils such as tea tree oil, coconut oil, essential oils, and oil of cedar leaf (such as Vicks VapoRub) to their nails as well. The effectiveness of these home remedies is highly doubtful. Application of household bleach and hydrogen peroxide is also not recommended due to lack of evidence that these treatments work. These agents can also cause unwanted skin irritation. Thickened nails that have been affected by fungus can be difficult to trim. Using topical urea cream will soften the nail and make it easier to trim. These creams do not require a prescription.

Are there over-the-counter treatments for toenail fungus?

The definition of over-the-counter (OTC) products means that they are available by ordinary retail purchase, not requiring a prescription or a license. Although there are few OTC medications aimed to treat fungal nails, many of these medications have not been tested and therefore are not approved by the U.S. Food and Drug Administration (FDA) for the treatment of onychomycosis. Most OTC agents are aimed at treating fungal infection of the skin rather than the nail. Some medications list undecylenic acid and/or propylene glycol as main ingredients. These ingredients inhibit fungal growth; however, they may not adequately penetrate the nail to be effective in treating fungal nails.

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Medication on top of money.

Are oral medications for nail fungus toxic?

The newer drugs are unlikely to cause any liver problems in patients without known liver disease. Blood tests are not needed for once-weekly treatment with fluconazole (Diflucan); however, people taking longer courses often have their liver function tested before starting the medicine and then retested during the course of treatment. It is important to notify the doctor of all side effects while on the medication. You should tell your doctor of all current medications to prevent potential serious drug interactions.

What about the cost of oral medications for fungal nails?

A further consideration is cost. Because newer oral antifungal agents are very expensive, some insurance companies balk at paying for what they consider a "cosmetic issue," unless nail fungus causes pain or other functional symptoms. Terbinafine and fluconazole are now available as generic drugs and are quite inexpensive.

A person wears sandals in in a gym locker room shower.

Is it possible to prevent fungal nails?

No one knows where a specific person catches the fungus, as it is everywhere. However, since the fungus does thrive in warm moist areas (like sweaty feet), there are certain areas one should avoid or use with caution. Shower floors, locker rooms, and swimming pools are suspected of being sources of the fungus, although there are no studies proving this fact. Nail polish and acrylic nails also make the nail less "breathable" and make the nail more susceptible to fungal infection. Fungi are everywhere -- in the air, the dust, and the soil. Hygienic measures such as spraying socks and footgear sound sensible, and perhaps these measures can even help a little bit. However, avoiding tight, nonbreathing shoes or steering clear of athletic facility floors may very well be the best prevention available. Daily washing of the feet and drying between the toes can help to prevent nail fungus. The fungi carried on the coats of pets, like cats and dogs, don't often cause nail fungus. Wearing white socks does not help.

What is the prognosis of fungal nails?

Curing fungal nails can be difficult and treatment can take up to 18 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.

Quick GuideNail Color and Texture: What Nails Say About Your Health

Nail Color and Texture: What Nails Say About Your Health
Photo of a woman's healthy toenails.

Is it possible to prevent the recurrence of nail fungus?

Tinea pedis, also known as athlete's foot or foot fungus, can cause recurrence of fungal nails. Therefore, it is important to manage this condition. One can apply over-the-counter (OTC) antifungal medicines such as clotrimazole (Lotrimin) or terbinafine (Lamisil) cream as directed to affected skin. Keeping footwear and socks clean can be helpful. You can also use portable UV light sanitizers to disinfect shoes.

Tips for prevention of fungal nails

Nail fungus causes only 50%-60% of abnormal-appearing nails. It can be hard to tell the difference between the different causes of discolored nails (even for doctors). Onychomycosis is often not treated. Reasons to receive treatment include

  1. diabetes,
  2. previous leg infection (cellulitis),
  3. if you have pain or discomfort from your nails, or
  4. you would like them treated for cosmetic reasons.

Treatment failures and recurrences are common.

Prevention is the key. The following preventive measures may be helpful:

  1. Keep your toenails short, and don't dig into the corners of your nails when cutting toenails.
  2. Keep feet clean, and dry them thoroughly.
  3. Wear dry socks and no tight shoes.
  4. Alternate your exercise shoes.
  5. Don't soak your hands in water or use harsh cleaners.
  6. Treat athlete's foot when it occurs.
Reviewed on 2/13/2017
References
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IMAGES:

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