A woman holds her feet and toes. Fungal infection of the nails sometimes makes the condition sound contagious or related to poor hygiene. Toenail fungus is much more common than fingernail fungus.Source: Getty Images
Thing to know about 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 a 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, a fungal infection. There are many other reasons why your nails may look different.
How do I get rid of toenail fungus?
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. In one study, ciclopirox got rid of the fungus 22% 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.
- Amorolfine topical solution 5%: 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 the 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.
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.
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).Source: Medscape/iStock/Fitzpatrick's Color Atlas & Synopsis of Clinical Dermatology Klaus Wolff, Richard Allen Johnson, Dick Suurmond Copyright 2009, 2005, 2001, 1997, 1993 by The McGraw-Hill Companies. All Rights reserved./"Infectionofcutical" by James Heilman, MD
What other conditions can be mistaken for fungal nails?
Here are some other conditions you may have instead of fungal nails:
- 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.
- 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.
- Whitish or yellowish nails can occur due to onycholysis. This means the 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.
- 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).
- 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 on the nails. The treatment is to trim the nail short every four weeks, don't clean it, polish it 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.
- 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.
- The swelling and redness of the skin around the nail are 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 for severe infection.
- 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.Source: iStock/CDC
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 a fungus that is caught in 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 an 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. 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.
Examples of distal subungual onychomycosis, proximal subungual onychomycosis, and candidal onychomycosis.Source: Medscape – Dr. Antonella Tosti
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. 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 an 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. 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 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 as Trichophyton mentagrophytes.
All ___________ have flat feet.
A doctor examines a patient's toenails.Source: Getty Images
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% 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 be 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.
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 a 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.
Who should be treated for fungal nails?
Medical treatment of onychomycosis is suggested in patients who are experiencing pain and discomfort due to 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.
Keeping nails trimmed and filed can help to reduce the amount of fungus in the nails. This also provides pain relief when thickened nails cause pressure-related pain.Source: iStock
What is the treatment for fungal nails?
Oral antifungal therapy has a high cure rate, 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. 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.
Rosacea, Acne, Shingles, Covid-19 Rashes: Common Adult Skin Diseases
A woman takes antifungal nail medication.Source: iStock
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 a 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 infections of the skin rather than the nail. Some medications list undecylenic acid and/or propylene glycol as the main ingredients. These ingredients inhibit fungal growth; however, they may not adequately penetrate the nail to be effective in treating fungal nails.
Subscribe to MedicineNet's General Health Newsletter
Medications, side effects, and cost.Source: iStock
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.
See a picture of fungal nail infecton and other fungal skin conditions
A person wears sandals in a gym locker room shower to prevent any fungal nails infection.Source: Sanna Lindberg / PhotoAlto Agency RF Collections
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. 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.
Is it possible to prevent the recurrence of nail fungus?
Tinea pedis, also known as athlete's foot or foot fungus, can cause the 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 the affected skin. Keeping footwear and socks clean can be helpful. You can also use portable UV light sanitizers to disinfect shoes.
6 Tips for prevention of fungal nails and keeping healthy toenails.Source: iStock
Tips for prevention of fungal nails
Nail fungus causes only 50% 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
- previous leg infection (cellulitis),
- if you have pain or discomfort from your nails, or
- 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:
- Keep your toenails short, and don't dig into the corners of your nails when cutting toenails.
- Keep feet clean, and dry them thoroughly.
- Wear dry socks and no tight shoes.
- Alternate your exercise shoes.
- Don't soak your hands in water or use harsh cleaners.
- Treat athlete's foot when it occurs.
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.
Medically Reviewed on 4/5/2022
Medically reviewed by Joseph Palermo, DO; Board Certificate: Internal Medicine/Geriatric Medicine
Baran, R., R.J. Hay, and J.I. Garduno. "Review of Antifungal Therapy, Part II: Treatment Rationale, Including Specific Patient Populations." J Dermatolog Treat 19.3 (2008): 168-175.
Brillowska-Dabrowska, A., S.S. Nielsen, H.V. Nielsen, and M.C. Arendrup. "Optimized 5-Hour
Multiplex PCR Test for the Detection of Tinea Unguium: Performance in a Routine PCR
Med Mycol. 48.6 Sept. 2010: 828-831.
Bristow, I.R., and M.C. Spruce. "Fungal Foot Infection, Cellulitis and Diabetes: A Review." Diabet Med 26 (2009): 548.
de Berker, D. "Clinical Practice. Fungal Nail Disease." N Engl J Med. 360.20 May 14, 2009: 2108-2116.
Derby, R., P. Rohal, C. Jackson, et al. "Novel Treatment of Onychomycosis Using Over-the-Counter Mentholated Ointment: A Clinical Case Series." J Am Board Fam Med 24 (2011): 69.
Gaburri, D., J.M. Chebli, A. Zanine, A.C. Gamonal, and P.D. Gaburri. "Onychomycosis in
Inflammatory Bowel Diseases."
J Eur Acad Dermatol Venereol. 22.7 JulY 2008: 807-812.
Garcia-Doval, I., et al. "Clinical Diagnosis of Toenail Onychomycosis Is Possible in
Some Patients: Cross-sectional Diagnostic Study and Development of a Diagnostic
Br J Dermatol. 163.4 Oct. 2010: 743-751.
Ginarte, M., Garcia-Doval, I., et al. "Observer Agreement in Toenail Disorders:
Implications for Diagnosis and Clinical Research."
Br J Dermatol. 160.6 June 2009: 1315-1317.
Gupta, A.K., L.E. Lynch, N. Kogan, and E.A. Cooper. "The Use of an Intermittent
Terbinafine Regimen for the Treatment of Dermatophyte Toenail Onychomycosis."
J Eur Acad Dermatol Venereol. 23.3 Mar. 2009: 256-262.
Kondori, N., A.L. Abrahamsson, N. Ataollahy, and C. Wennerås. "Comparison of a
New Commercial Test, Dermatophyte-PCR Kit, With Conventional Methods for Rapid Detection and
Identification of Trichophyton rubrum in Nail Specimens." Med Mycol. 48.7 Nov. 2010: 1005-1008.
Litz, C.E., and R.Z. Cavagnolo. "Polymerase Chain Reaction in the Diagnosis of Onychomycosis:
A Large, Single-Institute Study." Br J Dermatol. 163.3 Sept. 2010: 511-514.
Nair, A.B., S.R. Vaka, S.M. Sammeta, H.D. Kim, P.M. Friden, B. Chakraborty, and S.N. Murthy. "Trans-ungual
Iontophoretic Delivery of Terbinafine."
J Pharm Sci. 98.5 May 2009: 1788-1796.
Shemer, A., B. Davidovici, M.H. Grunwald, H. Trau, and B. Amichai. "Comparative
Study of Nail Sampling Techniques in Onychomycosis."
J Dermatol. 36.7 Jul7 2009: 410-414.
Shemer, A., H. Trau, B. Davidovici, M.H. Grunwald, and B. Amichai. "Onychomycosis in
Psoriatic Patients - Rationalization of Systemic Treatment."
Mycoses. 53.4 July 2010: 340-343.
Sigurgeirsson, B., J.H. Olafsson, J.T. Steinsson, N. Kerrouche, and F. Sidou. "Efficacy of
Amorolfine Nail Lacquer for the Prophylaxis of Onychomycosis Over 3 Years."
J Eur Acad Dermatol Venereol. 24.8 Aug. 2010: 910-915.
Smijs, T.G., and S. Pavel. "The Susceptibility of Dermatophytes to Photodynamic
Treatment With Special Focus on Trichophyton rubrum."
Photochem Photobiol. 87.1 Jan.-Feb. 2011: 2-13.
Sotiriou, E., T. Koussidou-Eremonti, G. Chaidemenos, Z. Apalla, and D. Ioannides. "Photodynamic
Therapy for Distal and Lateral Subungual Toenail Onychomycosis Caused by Trichophyton rubrum: Preliminary
Results of a Single-Centre Open Trial."
Acta Derm Venereol. 90.2 Mar. 2010: 216-217.
Takahata, Y., M. Hiruma, Y. Shiraki, Y. Tokuhisa, T. Sugita, and M. Muto. "Treatment of
Dermatophyte Onychomycosis With Three Pulses of Terbinafine (500 mg Day for a Week)."
Mycoses. 52.1 Jan. 2009: 72-76.
Thomas, J., et al. "Toenail Onychomycosis: An Important Global Disease Burden."
J Clin Pharm Ther. 35.5 Oct. 2010: 497-519.
Walling, H.W. "Subclinical Onychomycosis Is Associated With Tinea Pedis." Br J Dermatol. 161.4 Oct. 2009: 746-749.