Fungal Nail Infection

A fungal nail infection is usually caused by a fungus called Trichophyton.

Nails infected with a fungus may have the following characteristics:

• discolored
• dull, that is, no longer shiny
• thickened, with crumbling edges

If a toenail becomes thick, it can be painful to wear shoes.

Fungal skin infections, such as athlete's foot, often lead to fungal nail infections. It is most common in adolescent and adult males and is rare in women and children under age 12. The fungus that causes the infection lives in warm, moist environments such as showers and locker rooms.

A person is more likely to develop a fungal infection if he or she:

• fails to dry the feet well after swimming or bathing
• has sweaty feet
• walks barefoot in locker rooms and showers
• wears tight shoes and socks

It is difficult to prevent a fungal nail infection, but these steps can help:

• Wear a shower shoe or sandal in public places instead of going barefoot.
• Use an antifungal powder, such as miconazole, in socks and shoes.
• Keep socks clean.
• Wash socks each time with an antifungal solution, such as clotrimazole (i.e., Lotrimin, Mycelex), if you are susceptible to the fungus.
• Keep feet clean and dry.
• Go barefoot at home, whenever possible.
• Avoid use of nail polish and polish remover.
• Cut toenails straight but not too short.

Diagnosis of a fungal nail infection begins with a medical history and physical exam. The healthcare professional may cut a small portion of the nail plate. It is sent to a lab so the organism can be identified.

Fungus can cause the nail plate to come loose from the skin. This enables water or sweat to get under the nail. Bacteria can build up and cause skin breakdown. This can lead to a secondary bacterial infection which can spread to the connective tissue under the skin, a condition called cellulitis. Rarely, sepsis, or infection of the bloodstream, can occur.

Fungi may be transmitted to others who share bathing facilities or footwear.

Treatment of a fungal nail infection includes the following:

• trimming and thinning the nail plate
• applying topical imidazole medications such as clotrimazole (i.e., Lotrimin, Mycelex), miconazole (i.e., Monistat), butoconazole, tioconazole, econazole (i.e., Spectazole), ketoconazole (i.e., Nizoral), sulconazole (i.e., Exelderm), oxiconazole (i.e., Oxistat), terbinafine (i.e., Lamisil).
• applying topical unsaturated fatty acid derivatives such as propionic acid, undecylenic acid, haloprogin (i.e., Halotex), tolnaftate (i.e., Tinactin).
• applying topical ciclopirox (i.e., Penlac).
• taking an oral antifungal medicine, such as fluconazole (i.e., Diflucan), itraconazole (i.e., Sporanox), terbinafine (i.e., Lamisil)
• removing the nail temporarily and treating the area underneath with an antifungal ointment

In general, oral medications result in a much higher rate of treatment success.

Antifungal ointments may cause an allergic reaction. Oral antifungal medications may cause stomach upset or allergic reaction.

Antifungal medications are expensive and require monitoring by the healthcare professional for the duration of the treatment. Once the medicine is stopped, it may take several months before the nail plate is cleared of the fungus. The fungus often returns. Any new or worsening symptoms should be reported to the healthcare professional.