Toenail Fungus

Toenail fungus is diagnosed and treated by the Podiatry Division of Premier Medical Group.

What is toenail fungus?

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Also called onychomycosis, toenail fungus is any kind of fungal infection that occurs on or under one or more toenails. What starts out as a small white or yellow spot, usually under the tip of the nail, may eventually progress deeper into the nail causes additional symptoms and even potentially loss of the toenail altogether. Nail fungus can also affect the fingernails. Fungal infections more commonly occur in the toenails because shoes and socks create a dark, damp environment.


What are the symptoms of toenail fungus?

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The symptoms of toenail fungus depend on the type of infection, the duration and extent of the infection, and complicating factors that may be affecting other parts of the toes, foot, and body. The most common symptoms include:

  • Whitish to yellow discoloration, sometimes darkened with debris
  • Thickened nails
  • Distorted, misshapen nails
  • Brittle, crumbly, chalky, or ragged nails
  • Mildly foul odor

What are the types of toenail fungus?

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There are three main types of toenail fungus: subungual onychomycosis, white superficial onychomycosis, and candida onychomycosis. These different types of onychomycosis are defined by the nature of the fungus.

  • Subungual Onychomycosis: This type of nail infection is caused by dermatophytes, the same class of fungus that causes Athlete’s Foot. When the infection starts in the skin underneath the nail, it is called distal subungual onychomycosis. Less commonly, the infection may start at the base of the nail. In this case, it is called proximal subungual onychomycosis. There are about 40 individual species of dermatophytes that are grouped into three genera: microsporum, epidermophyton and trichophyton.
  • White Superficial Onychomycosis: This infection is caused by Fusarium or Acremonium. This infection occurs only in the top layer of the nail, first appearing as white spots. It is the easiest infection to treat because it is easy to get to. However, the infection may spread across the entire nail and cause it to become rough or crumbly. There are about 1,000 species of Fusarium and about 100 species of Acremonium.
  • Candida Onychomycosis: This type of toenail fungus is caused by yeast (Candida). Though less common in the nails, this is the most common type of fungal infection overall when you also account for infections that affect the mucus membranes and the GI tract. There are about 60 different kinds of Candida fungal species.

How is toenail fungus diagnosed?

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The doctor will examine your toenails. The doctor will also likely send a sample off to the lab to identify the nature of the infection. This can be done by clipping the nails or by scraping under the nail. Prescription medications may be recommended immediately, but knowing exactly what’s causing the infection can determine the best course of treatment. Other types of infection can cause similar symptoms, including yeast and bacterial infections. Though not an infection at all, psoriasis can also sometimes mimic toenail fungus.

What else causes toenail discoloration?

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Other microorganisms including bacteria can infect the nails. Chloronychia, or green-nail syndrome, is one notable example with these bacteria thriving in damp or wet conditions. Knowing the cause of your infection helps determine the best course of treatment. Again, it’s common for doctors to order lab testing. The dark discoloration can also be a secondary effect of fungal infection in which a misshapen toenail creates a space to harbor dirt and debris and spread the fungal infection to the entire toe.

Dark discoloration can also be a sign of physical trauma to the toe, either as a bruise or as dried blood that’s trapped under the nail. Physical trauma that doesn’t cause the blood vessels to break may result in white lines or streaks. Keep in mind, too, that the toes are an extremity that may not be as sensitive to pain as other parts of the body. It’s possible, especially if you don’t look at your toes on a regular basis, that toe discoloration is caused by physical trauma that the person has forgotten about or was unaware of.

Psoriasis can sometimes mimic a fungal infection of the nail even though psoriasis isn’t an infection at all but rather a skin disorder caused by an overactive immune system. Other causes of toenail discoloration include ingrown nails, skin cancer, certain inflammatory conditions, and Darier disease. Darier disease is an inherited condition characterized by a striped pattern on the toe and greasy, wart-like skin blemishes that have a bad odor.

Is toenail fungus painful?

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Toenail fungus is rarely painful at first. In fact, a fungal infection can fester for weeks or even months without being detected, especially if a person doesn’t regularly inspect their feet and toes. As the toenail fungus becomes more extensive and established, the toenail can thicken, grow brittle, and become misshapen. The toenail can become quite painful at this point. As the condition worsens, it may be difficult to wear shoes at all. Finally, the toenail may detach from the skin and/or fall off altogether.

Is toenail fungus contagious?

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Yes, to some extent. Most fungal infections require the right environment to take hold and begin to spread, and there are trace amounts of fungal spores in most places. However, coming into contact with a fungal infection or handling items that have been in contact with the fungus can increase the chances of getting an infection. Likewise, it’s advisable that you stop wearing old shoes and wash your socks once the infection is gone to reduce your chances of getting a new infection.

Athlete’s Foot is any dermatophyte fungus that occurs in the skin between the toes. In some cases, a fungal infection can spread among the toes and the skin between the toes. A weakened immune system and other complicating conditions may also increase your risk of getting toenail fungus and having it spread to other nails.

Does toenail fungus go away on its own? Are there home remedies?

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No, toenail fungus rarely goes away on its own. Despite mild symptoms that may go unnoticed for a long period of time, the infection is usually persistent and does not go away on its own. There are numerous home remedies for toenail fungus. You can try to apply baking soda, vinegar, mouthwash, hydrogen peroxide, or mentholated ointments (menthol, eucalyptus oil, camphor) to the affected area. However, it’s unclear how effective these remedies are. Baking soda likely helps simply by keeping the area dry without attacking the infection itself. In rare cases, this inhospitable environment may be enough to eliminate the infection. White superficial onychomycosis is much easier to treat with home remedies, while subungual infections are often more stubborn and may require medical treatment administered by a doctor.

In addition to at-home remedies, you can also buy over-the-counter anti-fungal ointments or creams. Trimming and filing the nail can be helpful, not only in removing accessible parts of the infection, but also so that anti-fungal ointments and creams can penetrate more deeply into the nail.

There is also a middle ground in which home remedies keep the infection from spreading but are unable to reduce and eliminate the established part of the infection. If the person stays diligent, the affected part of the nail may grow out. The bad news is that with larger, slow-growing toenails, this process can take as long as 12 months.

What is the treatment for toenail fungus?

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If home remedies don’t do the trick, if the infection spreads, or if the nail becomes painful, brittle, or misshapen, you need to see the doctor. There are several treatment options available. More than likely, you will be prescribed an oral medication. Terbinafine (Lamisil) and itraconazole (Sporanox) are two of the more popular and evidence-based treatments. Terbinafine is especially common for dermatophyte-based toenail fungus. Serious but rare side effects include liver damage and allergic reactions. Your doctor may prescribe an alternative to terbinafine if liver damage is a concern. However, nearly all anti-fungal medications have some level of hepatotoxicity.

A podiatrist will be also able to trim and file the nail more completely than the average person. More serious cases of toenail fungus may involve temporary or permanent toenail removal. A podiatrist can cut out the hardened nail while leaving the cuticle and underlying nail matrix. This directly removes the infection in the nail itself, while also allowing for direct access to treat the underlying skin with anti-fungal treatments while the nail grows back. In rare cases, laser treatment may be an option, but this isn’t covered by most insurance policies.

Recurring or treatment-resistant toenail fungus in which the infection spreads to the nail matrix itself may require permanent toenail removal. For persistent or complicated cases of toenail fungus, permanent removal of the nail may be recommended. This treatment can be an effective in eliminating future infections. However, it may be hard to ensure complete removal of the nail and the underlying nail matrix.

What are the complications and risk factors for toenail fungus?

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Diabetes and peripheral vascular disease reduce blood flow to the extremities. More prolonged courses of antifungal therapy may be required with these complications, as the reduced blood supply means more slowly growing nails and diminished capacity to fight infection. People with weakened immune systems are more susceptible to infections in general including toenail fungus. Also, physical trauma can create space where dirt and debris can become trapped and give rise to a fungal infection.

How to prevent toenail fungus?

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Some risk factors have more to do with lifestyle than medical conditions, and these lifestyle factors are also the best way to prevent toenail fungus. Keep your feet clean and dry as much as reasonably possible.

People who fail to change their socks and shoes every day. Wear shoes that breathe and have a comfortable fit. Trim your nails short. Wear shower shoes, especially when using public pools and locker rooms. Finally, begin treatment and visit your doctor when symptoms of toenail fungus first appear.