Health & Fitness

Potential Causes of Black Toenail- Its Treatment and Prevention


If your toenail starts turning black, it’s anticipated to be a bruise under a nail, scientifically called as subungual hematoma. Toenails are simply white in color. But color may change to black sometimes because of consistent applying of nail polish, malnutrition, infection, and trauma.

Black toenails can be awful-looking and sometimes irritating. There are several causes of black toenails, while some may treat easily or may heal on their own. We are going to discuss potential causes of black toenail in this article, plus treatment of black toenail and some suggestions for prevention.

Causes of Black Toenail

Black toenail may be benign or malignant. If you have developed a black toenail, it is important for you to understand some of its major causes.

If you feel yourself in doubt, then you should counsel a doctor who can detect your problem and guide an effective treatment plan.

1. An Injury under the Nail

Though, there are several possible causes of black toenail, but the most common cause by far is trauma to the toe. In this case, a black toenail may also be called as a “subungual hematoma”. This manifests that blood is flooding underneath the nail.

Runners and athletes often suffer this kind of injury under the nail, specifically while wearing tight shoes. Dropping something heavy on your foot can also result in a black toenail. The blood vessels in the nail bed can break, so blood can pool there.

Changing of color is not the only symptom of blood pooling. The extra fluid can exert pressure on the nail and the surrounding tissues. This can result in severe pain. If the injury becomes intense, the toenail may diminish entirely.

2. Repetitive Trauma

When you wear poorly-fitting footwear, you are at more risk of developing black toenails because of repetitive trauma. The long term pressure on your toes from poorly-fitting shoes can lead to severe problems such as small blisters and bloody blisters can be formed under the nail.

If the toenail trauma is not repetitive, the toenail can grow out naturally over a period of time without treatment. But if trauma becomes repetitive, it is likely that nail starts to fall off from the nail bed. You should consult doctor for better treatment.

3. Melanoma

Melanoma is the most aggressive type of skin cancer. It usually develops in the melanin producing cells. In rare cases, melanoma may cause a black toenail.

Direct exposure to UV rays is the major cause of melanoma. In such cases, skin begins developing one or more patches of dark, rough, and irregular-looking skin. These patches may grow under the nail bed. Melanoma does not develop rapidly, instead it takes time. It may not show symptoms, so you cannot notice it in the early stages.

4. Fungal Infections         

Fungal infection is one of the major causes of black toenails. A fungal growth or infection results in a white or yellowish discoloration. However, debris can arise near the infection and cause the toenail to appear black. Other than black color, fungal infections are also accompanied with odor and discharge.

Toenails are more susceptible to fungal infections because of socks and shoes which provide a warm and moist environment to fungal growth.

5. Underlying Conditions

Several underlying medical conditions may cause black toenails. They may include:

  • kidney disease
  • heart disease
  • obesity
  • cardiovascular disease
  • diabetes
  • anemia

You have to control the underlying condition first; as it will help the nail to recover its original color.

Can Black Toenail Cause Complexities?

Yes! Black toenail can be complicated sometimes. The fungal infection if left untreated can contact your feet and other parts of your body as well. If not treated on time, black toenail can even damage your entire nail.

Complexities can also result from melanoma in the toenail that’s confused with the trauma-induced black toenail. Whenever you feel your nail getting black, it’s important to seek medical assistance. Timely treatment will be helpful to retard the fungal growth and prevent it from spreading throughout your nail.


Treatment for the black toenails depends on its cause mostly. A doctor may induce a small hole in the nail by needle in case of blunt force injury. This hole will help the blood to flow and minimize the pressure.

In the case of severe infection, a doctor may prescribe additional medicines or anti-fungal creams to help heal the injury as soon as possible. If you are suffering from the repetitive injuries, like wearing poorly-fitting shoes, most likely a doctor will advice resting your foot and switching the shoes.

Before black toenails, if you’ve been diagnosed with some underlying conditions discussed above, it will be needed to treat first. See a doctor and follow a regular treatment regime.

You can treat a fungal infection at home. Applying anti-fungal lotions and ointments can be sufficient sometimes to get rid of the fungus. Fungi growth will be stopped and help the nail to heal. You can buy anti-fungal creams from your near pharmaceutical store or order it online. But, if the infection remains even after a few days, it is better to consult a doctor now.

In cases when the black toenail becomes quite serious and seems to be cancerous, a doctor will analyze all the possible treatment options available.


Doctors suggest following precautionary measures to avoid black toenail.

  • Try to wear toe pads of silicone. Pads made of silicone help absorbing some of the pressure while running.
  • Try wearing a shoe that fits to your foot. While buying running shoes, visit a brand that specializes in the sports kind of shoes to get a perfect fitting. Wear good footwear at gym specifically. When using a public shower, try to wear perfect footwear. 
  • Make sure to have enough room in the toes. This is the best way to get good running shoes. Do not buy shoes with extra space in the toes; it can make your foot slides around in the shoe. Also, consider your socks fitting while buying shoes so your toes do not pinch at the top.
  • Do not grow your toenails long. The short toenails will not hit the top or side of your shoe while running. Always cut your nails in a correct manner to prevent ingrown toenails.
  • Adjust the laces and tie them properly. This may help you getting a better shoe fit.
  • Quality of socks matter a lot. Buy good socks to prevent moisture either from sweaty feet or the weather. This may decrease the minimizing effect and friction. High quality socks will prevent the moisture that can harm your skin and nails.
  • Wear sunblock to avoid overexposure to UV radiations.

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