Nail fungus is an infection that can cause one’s toenails to thicken and change color. There are three types of fungus that infect the nail: dermatophyte, yeast or mold. Onychomycosis is more common on the toenails than the fingernails. Fungus grows easily in dark, moist, damp areas such as the toes and feet. Athlete’s foot can spread to involve the nails or alternatively, onychomycosis can lead to Athlete’s foot. However, it is not easily spread from person to person. Onychomycosis is more common in older adults and in men more than women. As we age, our nails become dryer and more brittle and therefore, crack more easily. These cracks provide an opening for the fungus to enter. Other risk factors for the development of onychomycosis include diabetes, circulatory problems, excessive sweating and a weakened immune system.

Nail Fungus


Infected nails appear yellowed or brown and as the fungus grows it causes the nails to thicken and become deformed. As the infection continues crumbly debris builds up under the nail. The debris can be foul smelling. The nails become brittle and when they break they can leave sharp shards of nail that can be quite painful.

Nail Fungus


Treatment is dictated by the severity of the infection as well as by the type of fungus causing the infection. It takes months to see improvement with treatment and recurrence is common. Therapies include topical and systemic medications as well as laser treatments. Some topical treatments include urea to thin the nail plate as well as prescription creams and lacquers. Oral antifungal medications are more effective however, they also come with a higher risk of side effects including rashes, liver toxicity and dygeusia. Patients with liver disease, congestive heart failure or who take certain medications should not take oral antifungals.

Nail Fungus

*This webpage is for informational purposes and is not intended to be, and should not be relied upon as, medical advice. Any medical concerns should be addressed with a physician.