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Toenail Fungus

Q & A

What Is Toenail Fungus?

Toenail fungus, or onychomycosis, is an infection underneath the surface of the nail caused by fungi. When the tiny micro-organisms take hold, the nail often becomes darker in color and debris may collect beneath the nail plate, resulting in thicker nails that are difficult to trim and make walking painful when wearing shoes. 


Your toenails are especially vulnerable to fungal infections because they spend so much time in a dark, warm, moist environment where fungi can easily grow—your socks and shoes. Walking barefoot in communal areas like swimming pools, locker rooms, and showers make your feet more susceptible to all types of infection, including fungal infection. 

Fungi also spread easily. You can catch a fungal infection from someone else, and fungal infections can spread from other parts of your body to your toenails, especially athlete’s foot, which affects the skin between the toes.  Other contributing factors may be a history of athlete's foot and excessive perspiration. 


Not everyone gets fungal infections under these conditions though. Those who suffer from chronic diseases, such as diabetes, circulatory problems, or immune-deficiency conditions, are especially prone to fungal nails.


If you notice any of the following signs on one or more of your toenails, you may have a fungal infection:

  • Thickened or brittle texture

  • Scaling under the nail

  • White or yellow streaks or spots on the nail

  • Flaking and pits on the surface of the nail

  • Crumbling in the corner or tip of the nail

  • Foul odor


Not all changes to the appearance and texture of your nails result from fungal infections. Based on your symptoms, Dr. Tien will determine if you have a nail infection, identify what type of nail infection you have, and from there, develop a treatment plan.

Diagnosis and Treatment

Treatments may vary, depending on the nature and severity of the infection. Your podiatrist can detect a fungal infection early, perform a lab test, determine the cause, and form a suitable treatment plan, which may include prescribing topical or oral medication, and debridement (removal of diseased nail matter and debris) of an infected nail.


Oral antifungals, approved by the Food and Drug Administration, are the most effective treatment. Dr. Tien may also prescribe a topical treatment, which can be an effective adjunct treatment modality for fungal nails. Have you been prescribed Jublia? Please see the Patient Information Sheet for further instructions on application and use. 

In some cases, temporary removal of the infected nail can be performed to permit direct application of a topical antifungal. Permanent removal of a chronically painful nail that has not responded to any other treatment permits the fungal infection to be cured and prevents the return of a deformed nail.



Proper hygiene and regular inspection of the feet and toes are the first lines of defense against fungal nails. Clean and dry feet resist disease.

  • Wash your feet with soap and water, remembering to dry thoroughly.

  • Wear shower shoes when possible in public areas.

  • Change shoes, socks, or hosiery more than once daily.

  • Clip toenails straight across so that the nail does not extend beyond the tip of the toe.

  • Wear shoes that fit well and are made of materials that breathe.

  • Avoid wearing excessively tight hosiery to decrease moisture.

  • Wear socks made of synthetic fiber that “wicks” moisture away from your feet faster than cotton or wool socks do.

  • Disinfect instruments used to cut nails.

  • Disinfect home pedicure tools.

  • Don't apply polish to nails suspected of infection (those that are discolored, for example). 

  • Treat athlete's foot  if present.

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