The most common cause of thick, yellow and ugly toenails is nail fungus. Usually, you can blame the same fungus that causes athlete's foot for causing your fungal toenails. Fungus takes time to “set up shop,” but once it does, it will slowly take over the nail. The more time you take to get your nail treated, the worse your nail will look. Fungal nail infections typically do not get better “on their own.”

The infection usually starts at the tip of the nail and works its way back. Fungus is not painful in the beginning, and is usually not noticed until the nail looks pretty bad. Fungus is not picky and can infect just one, or several toenails. Over time, the nail will become thick, yellow, dark, crumbly, may grow debris underneath the nail and can start to separate the nail from the skin.

Sweaty feet can contribute to the infection process and allow the fungus to spread. The fungus prefers an environment that is moist, dark and warm, which is why it affects the toenails much more often than fingernails. Fungus is an infection of the skin and does not spread through the blood stream. It is often found on the bottom of the foot or between the toes. Fungus is not highly contagious, and family members are almost as likely to contract it from some other source as they are from the family member who has the infection. Even so, keeping common showering areas clean is recommended, and sharing shoes should be avoided.

Not all thick, yellow, or crumbly toenails are caused by a fungal infection. There are a number of other problems that can cause nails to “look” fungal such as injury, eczema, psoriasis, bone spurs under the nail, certain prescription medications, and a variety of chemicals found in lower end nail polishes (like formaldehyde).

Injury to a toenail can cause the nail to grow in a thickened or malformed fashion, and may even discolor the toenail. Sometimes a nail injury may even cause the nail to fall off. The “ugly” appearance of a nail can be due to an established fungal infection or may be due to the damage caused to the nail root when it was injured. If the nail “looks bad” because of problems not related to a fungus, treatment with anti-fungal medications will not correct the malformed nail.

The only way to confirm there is a fungus within the nail is to take a biopsy. This can be done in the office without anesthesia. The procedure is painless and only takes a few minutes. The biopsy is then sent to the lab to confirm the diagnosis and the results are received within a few days.

* Our next article deals with how to treat fungal nails.