Onychauxis is a nail disorder that causes fingernails or toenails to grow abnormally thick. Over time, the nails may become curled and turn white or yellow.

This thickening of the nail may force the nail plate (the part you paint with nail polish) to separate from the nail bed. Though toenail fungus can cause similar symptoms, onychauxis isn’t caused by a fungus. However, your risk for developing a fungal infection increases if you have this nail disorder.

Onychauxis, which is sometimes called hypertrophy of the nail, is more common in older adults. The older you get, the more likely you are to experience this condition.

Symptoms of onychauxis include:

  • abnormal thickening of the nail
  • separation of the nail plate from the nail bed
  • yellow or white appearance
  • red or black coloring if left untreated
  • brittle crumbling around the edges of the nail
  • pain

Symptoms may become more severe if onychauxis is left untreated. The nails may begin to curl, and they may become so thick it’s impossible to trim or maintain them. That, in turn, can make treating the nail disorder more difficult.

Onychauxis may be the result of several conditions or issues. Your doctor can diagnose what the underlying issue for your abnormal nail growth is.

The most common causes for onychauxis include:

  • Hereditary causes. If one or both of your parents have this nail condition, you’re more likely to develop it.
  • Acute trauma. Stubbing your toe or dropping a heavy object on it can cause trauma to your nail bed and nail plate. The trauma may cause nail thickening. In some cases, this may be temporary until the nail heals.
  • Chronic trauma. Individuals who inflict a good deal of pressure on their feet for long periods of time, such as athletes, dancers, or runners, may be more likely to develop this nail disorder. The long-term stress on the nail beds and nail plates may trigger the unusual growth. Wearing shoes that are too tight or too small can also cause this condition.
  • Acromegaly. This hormonal disorder is the result of too much growth hormone. Though rare, it can cause nails to growth denser.
  • Psoriasis. This skin condition causes thick patches of scaly skin, and it can cause nails to grow thicker and more brittle. More than half of people with psoriasis will experience nail psoriasis, too.
  • Reduced circulation. Without a proper supply of nutrients, your nails may be unable to grow properly.
  • Diabetes. People with diabetes commonly develop thick nails. This may be a complication of the disease, or it may be the result of reduced circulation, which is also common with diabetes.
  • Darier disease. A genetic skin disorder, Darier disease causes wart-like blemishes that may be yellow, emit a strong odor, and are hard to the touch. This condition can also cause nail abnormalities, including white and red stripes in the nail plate and unusual thickness.
  • Infection. A yeast or fungal infection in the nail bed or around the nail plate can cause symptoms, including discoloration and thicker nails.
  • Pityriasis rubra pilaris. This rare skin condition causes chronic inflammation and reddish-orange scales or blotches on the skin. It can also lead to nail thickening, discoloration, and shedding.

Onychauxis isn’t contagious, and it can’t be spread from person to person directly. It’s possible you could inherit the gene that increases your risk for this condition from a parent. However, touching the nails of a person with this disorder will not increase your risk for developing it.

That being said, people who have onychauxis may be more likely to develop a toenail fungus as a result of this condition. Some types of toenail fungus can be spread through contact with another person.

Treatment for onychauxis falls into two main categories: medical treatments and home remedy options. There isn’t standard treatment for this condition. Instead, your doctor will decide a course of action based on a suspected cause and your specific symptoms.

It’s important to note that you don’t have to treat this condition unless it becomes painful and interferes with your day-to-day activities. However, many individuals will seek out a treatment or diagnosis for an underlying condition because the nails may be unsightly.

Medical treatments for onychauxis

Treat underlying conditions. If you have this nail growth issue, your doctor may want to identify potential issues that could be causing it. In some cases, there isn’t an underlying issue, but if one can be found, it can be treated. Treatment means the thick growths and discoloration may stop.

Removal of the affected nail. In extreme cases, your doctor may choose to remove a portion or all of the thickened nail. This is an option when the nail becomes so thick you experience severe pain and can’t properly care for it on your own anymore.

Home remedy options

Keep neat, trimmed nails. Trimming your nails frequently will help with their appearance. It may also ease some pain if nails rub against shoes and cause discomfort. If your nail clippers aren’t thick enough to tackle the job, talk with your doctor about any special tools you may need. Eventually, you may need to see a podiatrist, a doctor who specializes in the treatment of conditions and diseases of the foot, ankle, and lower limbs.

Wear comfortable shoes. Tight shoes may cause onychauxis, and they may make symptoms, especially pain, worse. A professional shoe fitting can help you decide if you need a wider shoe option so your toes have plenty of room. Wide-toe shoes may be a smart option if you frequently experience pain from toenails rubbing against your shoes.

Paint with a polish. Nail polish may help cover the discoloration, but it will not end or stop the abnormal growth.

Move more. Boost circulation in your lower extremities by walking, riding a bicycle, or otherwise moving more. The increase in blood, oxygen, and other nutrients may end the unusual nail growth issue.

Onychauxis may seem worrisome, but it’s rarely dangerous and unlikely to cause serious side effects.

In some cases, onychauxis can be treated. This is especially true when the abnormally thick nails are the result of an underlying condition, such as an infection or trauma. It may take time — nails do grow slowly — but it’s likely you can recover normal nail growth.

If onychauxis is left untreated, you may eventually experience complications like curled toenails, thick nails that cannot be trimmed, and pain. In this case, a doctor may have to help you trim and maintain the nails so that they don’t interfere with your day-to-day life.

Unfortunately, it may not be possible to prevent onychauxis. However, keeping your nails trimmed and clean, wearing light shoes with wide toes, and getting exercise may all help reduce your risk for this nail disorder. If you believe you may be developing onychauxis, make an appointment to see your doctor. Early treatment may help stop and reverse the condition.