Do you feel self-conscious about your toenails? You are not alone. Many ordinary conditions can cause thickening or discoloration of the nails – several of which are treatable with podiatric foot care. Here are the most common reasons why you may have noticed a recent change in your toenails.

What Causes Thick Toenails?

Even if you do not care to seek treatment for it, you may wonder why your toenails have gradually become thicker. Thick toenails are the common result of four different causes: injury, old age, fungal infection and psoriasis.


Inside each of your toes are growth cells. These continually produce the keratin your nails are made of, which is why your nails grow. Like any other part of your body, your toe’s growth cells can stop working correctly when they become damaged. A badly injured toe may never grow a nail again. A foot injury may alternatively leave the growth cells’ ability to produce keratin intact, but instead prevent the keratin from flattening down as it meets the established nail plate. A single foot injury may cause one or more toes to begin growing thick toenails. Runners and other athletes often get thicker toenails as well, as the years their toes spent bumping against their shoes’ toe boxes is an example of repetitive trauma.

Old Age

Advanced age can cause toenails to become thicker for a few reasons. A new health condition, such as reduced blood flow, can impact healthy function of the toes’ growth cells. A lifetime of work and exercise may have caused the same kind of repetitive trauma received by athletes. Loss of mobility and the hand strength needed to operate nail clippers can also make normal nail maintenance more difficult.

Fungal Infection

Onychomycosis, or nail fungus, is a common condition with over three million cases per year in the United States. Multiple fungi species can cause onychomycosis, the symptoms of which typically include brittle, ragged or thickened nails. Anyone can get onychomycosis. Athletes are prone to toenail fungus, as athlete’s foot makes their feet more susceptible to infection by other fungi. Diabetes and other diseases which affect blood circulation can predispose patients to nail fungus; so too can HIV and other diseases which weaken the immune system. Even a simple injury may result in nail fungus.


As a chronic autoimmune disease, psoriasis can increase vulnerability to fungal infection by weakening the body’s immune system. The dry, patchy rash which is frequently a symptom of psoriasis may also spread to the skin beneath and around the nails. When the rash spreads to the nail itself, the nail becomes brittle and thicker. There is currently no known cure for psoriasis, although several treatments for nail psoriasis do exist. Nail psoriasis is manageable by keeping nails short, dry, moisturized and protected. A variety of medications for nail psoriasis are also available by prescription from your podiatrist.

What Causes Discolored Toenails?

The self-conscious among us take relief that discolored toenails are easy to cover up. But your health may be far better off in the long run if you seek podiatric care for certain conditions that discolor toenails, as some can also cause pain and eventually cause a nail to fall off.

Fungal Infection

Fungal infection may do more to a toenail than thicken it. If you notice black, blown, green or yellow coloration in one or more toenails, that could also indicate the presence of nail fungus. The toenail’s discoloration may indicate which type of fungus caused the infection. Yeast infections of the toenail are typically whitish in color; mold infections are brown, and dermatophyte infections are yellow. Each of these pathogens is best treated differently, so a prescribed medication will likely prove more effective than an over-the-counter one.


If you have recently injured your foot or frequently wear tight-fitting shoes, you may have received a dark spot beneath your toenail. This is a subungual hematoma: a collection of blood and other fluid produced by damaged blood vessels beneath the toenail. A subungual hematoma can be quite painful, and requires medical attention if the bleeding does not stop on its own. Fortunately, a typical case of subungual hematoma resolves itself as normal nail growth eventually pushes the mass free from the toe.


In addition to thickening toenails, diabetes may also discolor them. This is not solely because people with diabetes are at greater risk of fungal infection. Because diabetes affects the body’s normal ability to break down sugar, it can also change the color of the collagen within the nail beds. The nails may appear yellow as the result, although this discoloration is not harmful and does not require treatment.


Toenail thickening is not the only possible symptom of nail psoriasis, either. If you have psoriasis, there is a 50 percent likelihood you will also be affected by nail psoriasis, which may cause the skin beneath your nails to turn brown, yellow, pink or red in color. Nail psoriasis may also cause pitting of the nails, as well as horizontal ridges or dents known as “Beau’s lines.”


Subungual melanoma, which manifests itself beneath the toenail, is quite rare. But because early melanoma detection is key to receiving the most effective treatment, it is important to check your entire body – including your toenails – every month for newly formed spots that exhibit the “ABCDEs” of melanoma:

  • Asymmetry – One half of the spot looks unlike the other half.
  • Border – The spot’s border is poorly defined or otherwise irregular.
  • Color – The spot consists of varying shades of color.
  • Diameter – The spot is greater than 1/4 inch in diameter.
  • Evolving – The spot is changing in any of the above attributes.

Subungual melanoma can only be diagnosed after your doctor has conducted a biopsy. If you ever suspect that a spot on your feet is skin cancer, consult your podiatrist, dermatologist or primary care physician at your soonest convenience.

Nail Polish

Nail polish may contain ingredients which chemically react to nails. One of these is formaldehyde, which can turn nails yellow after a few days of exposure. Do not risk damaging your nails by attempting to scratch off nail polish staining. Instead take a break from polishing your nails, let them regrow, and try wearing a base coat and sticking to lighter colors in the future. If you have any concerns about the thickness or coloration of your toenails, then the passionate podiatrists of Twin Cities Foot & Ankle Clinic are available to see you right away. We welcome you to contact us today to schedule a visit at our convenient location in Golden Valley, Minnesota!