What the Heck is Onychomycosis?


Mycotic (fungal) toenail infections are a common condition. In fact, most people over 75 years of age have some degree of infection. The fungal organisms that cause toenail infections are common. The spores responsible can be found in your shoes, in the soil and basically everywhere on the Earth. The thought is that the longer you’re on the Earth, the better your chance of developing an infection. The same fungal organisms that cause nail infections also cause infections of the skin, scalp and other parts of the body.

The thickening and discoloration can vary in the number of toenails affected and the severity of the infection. The great toe and fifth toe are typically the most symptomatic, followed by the second, third and fourth toes. Infections range from totally pain-free to severely painful. Pressure on the toe(s) from poorly fitting shoes will make the affected nail more painful. Thickened toenails may become ingrown, or fluid can develop and be trapped beneath the nail.

Diagnosis of a fungal nail infection is generally based upon clinical judgement. Other conditions can cause thickening and discoloration of the toenail, such as repetitive trauma, psoriasis, acrylic nail applications and pigments from nail polishes. Mild discoloration and thickening that does not respond to topical medication may benefit from a toenail culture and PAS/KOH stain to determine treatment. A fungal PCR test is available; however, the test is expensive and almost never changes the treatment. Finally, despite a strong clinical presentation of a fungal toenail, the tests to detect fungal elements within the nail plate are often negative.


Onychomycosis occurs in 10% of the general population, 20% of persons older than 60 years and 50% of those older than 70 years.


If you have a thickened and discolored toenail, I suggest applying a topical antifungal daily for at least six months, as it takes up to 12 months for a toenail to fully grow out. I suggest you take a “before treatment” picture with your cell phone so you can track the improvement. An abundance of topical items for treating the condition are endorsed on various social media platforms. I recommend tried and true antifungals that are reasonably priced. Please refrain from soaking your feet in bleach or any caustic solutions, as these are damaging to your skin and have not proven to be effective.

A variety of over-the-counter (OTC) and prescription products are available for treating fungal nails. Topical medicine generally works in mild cases and has little to no side effects – they can prevent more severe infections from getting worse, but rarely resolve the condition. Prescription topical medications offer little advantage over OTC products and are prohibitively expensive. (Many of today’s OTC products were formerly prescription medicines.) I don’t recommend prescription fungal nail products due to high cost, low compliance and poor efficacy.

Despite social media claims, topical treatment for fungal toenails is often unsuccessful. Oral antifungal prescriptions are generally safe and effective, provided you’re not taking other medications that interact with the antifungals. You should also not take oral antifungals if you have preexisting liver disease or drink excessive alcohol. Many of the oral antifungals have been on the market for over 20 years, have a proven safety profile, are inexpensive and are generally well tolerated. Typically, the oral meds are taken for 90 days; their efficacy ranges from 65-99% with the average being 80% effective.

The mainstay of treatment for a fungal toenail is sharp debridement. Debridement is the physical removal of much of the mycotic portion of the infected toenail, so the topical or oral antifungals can be more effective by penetrating the deeper portion of the nail. Debridement is considered a surgical procedure by Medicare and other private insurance companies; however, it can be performed in an office setting with minimal pain.

Once the infection is resolved, many people will have a recurrence. Weekly application of topical antifungals can be an effective prophylactic. Recalcitrant or non-responsive mycotic toenail infections may require permanent partial or total nail excision (surgical removal) or additional doses of oral antifungals.

In summary, fungal toenail infections are common. Many are treatable and significant improvement can be made in appearance and related pain. Treatment begins with debridement and topical antifungals. If the topical medication does not help, oral antifungals are recommended, provided there are no contraindications.


Alternaria is a fungus that causes onychomycosis



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