Black Toenail: Is It Trauma, Fungus, or Something Way Worse

Many times throughout my career as a podiatrist I've had patients come to me with big toenails that have turned black. Most often a black toenail is simply the result of nail trauma. The nail turned black because they're a runner or a skier and they wore shoes or boots that were just too tight. Or they loved to tinker with their car and they dropped a tire iron on their toe. Sometimes kicking a solid object too hard can also cause a blackened nail to arise.

But sometimes a black toenail can be the sign of toenail fungus or even worse, melanoma.

That's why it's so important to make sure to see a Seattle podiatrist if you notice your toenail is black or turning black.

Fungal Nails

Onychomycosis or fungal nails are a very common occurrence. In Seattle, our feet are covered in socks and shoes or boots most of the year. And many of us wear cotton socks that keep our feet slightly damp. This is the perfect environment for toenail fungus to thrive.

Some of us are more prone to nail fungus due to our genetics.

Runners and other active people also are at greater risk due to repetitive pressure on the nail bed which causes it to lift slightly allowing the fungus in where it can set up shop.

Fungal nails can be difficult to treat particularly if it's been a longstanding problem and the nail has thickened or the patient is immunocompromised.

It's best to get this condition treated as early as possible to ensure the best chance of success. Even so fungal nails can return just like a chronic case of gingivitis. Prevention is key for those who've had it by limiting their exposure--using socks that wick away moisture, alternating shoes on a daily basis, or using a UV light shoe sanitizer.


At worst a black toenail is diagnosed as melanoma, a very dangerous form of skin cancer. Melanoma tends to grow very slowly so it's important not to dismiss it. In fact, melanoma is the most common cancer of the feet. Unlike our face which we look at every day, many of us ignore our feet.

When found on the feet there is a much higher death rate due to this cancer which can spread throughout the body. That's because we are more likely to find it when it's already too advanced to adequately treat.

Call us today at 206-368-7000 for an appointment. Often same day for emergencies and less than 2 weeks for chronic foot pain. You can also request an appointment online.

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Seattle foot and ankle specialist, Dr. Rion Berg offers foot care for patients with bunions, heel pain, diabetes, fungal toenails, ingrown nails, and surgical solutions when needed to residents of Seattle, Bellevue, Kirkland, Shoreline, Lake Forest Park, Mountlake Terrace, Lynnwood and other surrounding suburbs.

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