Have a Black Toenail? Here are 3 Reasons Why… | Triad Foot & Ankle Center

Have a Black Toenail? Here are 3 Reasons Why…

Black toenails are a common occurrence with runners, who sometimes tout their discolored nail as a badge of honor. After all, black toenails are injuries that are the result of blistering, bleeding, and/or bruising underneath the toenail, usually on the big toe, as a result of repetitive friction or bumping of the toenail. Running is a natural culprit because of this, especially for those who run long distances, such as marathoners. Trauma can be severe or mild, ranging from blistering under the nail bed to complete detachment of the nail.

However, not all black toenails are from running. If you aren’t an avid runner or athlete there may be another explanation:

  1. Your shoes don’t fit. Because black toenails are usually the result of repetitive trauma, tightly fitting shoes without enough room in the toe box can sometimes cause black toenails to occur. If a black toenail shows up after a particular workout or long walk, you may need to evaluate the shoes worn during the activity. Be sure that when purchasing shoes, especially tennis shoes, you have your feet properly fitted by a professional at a shoe store. Avoid ordering shoes online without having tried them on first unless it’s a brand that you are very familiar with in terms of sizing.


  1. You have an infection. A black toenail that is accompanied by red, inflamed or oozing skin surrounding the toenail is a sure sign that more is going on than a little blood under the nail. Athlete’s foot can actually spread to your toenails and turn them shades of yellow, blue, green, brown, purple and yes, black. If this happens, it’s time to head to the podiatrist to stave off a growing problem. Mild cases are often addressed with topical medication, while more aggressive infections may require oral medications or laser treatment.


  1. You have a subungual hematoma. Dropping a heavy object onto your toe can be incredibly painful, as many of us know. It can cause the blood vessels under your nail bed to burst and cause blood to pool underneath the nail, known as a subungual hematoma. Naturally, this build-up of blood can cause throbbing pain and intense pressure. It is never advised that you attempt to drain the blood underneath the nail yourself. Rather, make an appointment with a podiatrist who can use sterile tools to safely drain the blood and prevent infection without pain.


Sometimes trauma to the nail bed, whether it be repetitive or acute, requires no treatment and the toenail and nail bed will heal over time. There are other times, however, when blisters underneath the nail can cause the nail to detach from the nail bed. This might take the form of a partial detachment, where only a piece of the toenail lifts from the nail bed, or a total detachment when the entire toenail falls off. Partial detachments are generally more painful than full detachments. Once the nail fully separates from the nail bed, it becomes dead tissue and will never re-attach, making it no longer painful. The downside is that a toenail on the big toe can take anywhere from six months to a year to grow back! In the event of a partial detachment, visit your podiatrist right away so that the rest of the damaged nail can be safely removed, allowing new nail growth to come in unhindered by any remaining damaged nail.

If you have a discolored toenail, regardless of coloring, it’s best to have it examined by a professional for proper diagnosis and treatment! Request an appointment with one of our podiatric specialists today for a foot exam by clicking here or call any of our convenient office locations in the Piedmont Triad.

Disclaimer: The information and other content provided in our blogs, videos, or in any other content or linked materials are not intended and should not be construed as medical advice, nor is the information a substitute for professional medical expertise or treatment. For a full disclaimer, please click here.