Onychomycosis is a condition that involves a fungal infection of the fingernails or toenails. It is also sometimes referred to as dermatophytic onychomycosis or tinea unguium.

Epidemiology

It is an extremely common condition and was found to the most frequent fungal foot infection in a survey of foot diseases undertaken in 16 European countries in 2003. It is estimated that its prevalence is approximately 27% across the general population, which increases with age.

In some other populations it has been observed to be somewhat less prevalent and it is estimated to be approximately 6.48% in Canada.

Some health conditions increase the risk of being affected by onychomycosis significantly. Up to one third of all diabetics are affected by the condition and for people that suffer from psoriasis it occurs up to 56% more frequently than in the general population.

Causes

The condition may be caused by dermatophytes, Candida albicans or nondermatophytic molds. These pathogens penetrate the nail to cause an infection underneath the nail and the resulting symptoms.

Some risk factors may increase the likelihood that an individual will be affected by nail fungus. Elderly people are more likely to be affected as their nails typically grow slower and are thicker than usual, which provide optimal conditions for growth of the infection. Additionally, people affected by certain health conditions, such as diabetes and psoriasis, are more likely to experience symptoms of onychomycosis.

Symptoms

Initially, the physical changes to the nail and surrounding skin are the first symptoms to be reported. The nail and tissue is often discolored to a white or yellow color and the nails can become thick and brittle, causing them to break more easily.

The appearance of the nail, particularly on the fingers, can cause people to feel self-conscious about the infection when in social situations. This can result in anxiety when people are in social situations and problems relating to other people.

If left untreated, the physical symptoms can worsen significantly and lead to inflammation of the area and pain. This only happens in severe cases and is not reported by most people who suffer from the condition.

Diagnosis

Initially, the diagnosis is usually made upon visual examination of the nails and the suspected infection. There are several conditions that cause similar symptoms, so it is important that differential diagnosis is made to ensure the optimal treatment is chosen.

Laboratory tests are often needed to confirm diagnosis. These usually involve a skin sample or scraping of the nail, which is inspected using a variety of laboratory methods.

Treatment

Currently available treatments can be divided into orally and topically administered treatments. Oral treatments are generally more effective and include terbinafine, itraconazole and fluconazole. Topical treatments include a liquid to be painted onto the affected nails containing ciclopirox, amorolfine or efinaconazole. More effective results may be achieved with a combination of oral and topical treatments.

It is relatively common for the infection to recur, even after effective treatment. The rate of recurrence is believed to lie between 10-50%, although is not precisely known.

Complications

In particularly severe cases, onychomycosis may lead to other serious infections. This risk is amplified when the immune system is suppressed due to medication or other health conditions, such as AIDS and diabetes.

Osteomyelitis is an infection of the bone, which is a possible complication that may result from onychomycosis. This is rare but may affect some individuals with severe outcomes.

To prevent complications from occurring, it is recommended that treatment is commenced at the earliest possible point once the diagnosis has been confirmed.