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Black Toenail

Last reviewed by Editorial Team on August 13th, 2018.

Everyone has had a black toenail, at least once in our lives. In the majority of the cases, as you will have the opportunity to read below, the black toenail appears after an injury. However, there are other causes that can lead to the appearance of a black toenail, such as the intense physical effort. In fact, because this condition is often encountered in professional athletes, it is also known as the runner’s toe.

In the situation that the toenail turns a black color, without any known injuries having occurred, it is for the best that you visit the doctor. After he/she will make an accurate diagnosis, you will also be prescribed the correct treatment.

Symptoms of Black Toenail

black toenail
These are the most common symptoms associated with the black toenail:

  • Blood collection under the nail bed (hematoma)
  • Discomfort or pain at the level of the respective toenail
  • Pressure sensation
  • Foul odor (sign of fungal infection)
  • Discharge from under the toenail
  • Redness and warmth
  • Inflammation
  • Separation of the toenail from its bed (partial/complete – more severe cases).

Black Toenail Causes

There are many reasons why a toenail can turn a black color, one of the most common ones being the physical injury or trauma to the respective toenail. It is important to understand that the characteristic black color is caused by the collection of blood under the nail bed. As the injury begins to heal, the blood dries up and turns a black color, which leads to the specific aspect of the injured toenail.

Even though the black toenail is often encountered in the general population, it is said that there are people who present a higher risk for such problems. In the high-risk category, you will find those who are professional athletes and also who are accustomed to walking barefooted (higher risk of physical injury, which will cause the toenail to turn a black color).

Another common cause is the potential fungal infection. This is often seen in those who have a weakened immune system or in those who do not maintain adequate hygiene measures. The fungal infection can be transmitted from one person to the other, through shared objects of personal hygiene or it can be acquired from public places (especially where there is a lot of humidity, such as public swimming pools or showers). In some cases, the black toenail can actually represent an underlying melanoma, which is an aggressive form of cancer.

It is essential to mention that the repeated trauma can also cause a toenail to turn black. This is often seen in those who are professional athletes, performing intense physical activity on a regular basis. Inadequate footwear can place a lot of pressure on toenails, causing circulatory problems and leading to the appearance of a black toenail.

When to see the doctor

These are the situations in which you should consider visiting the doctor:

  • Infection
    • Purulent discharge
    • Foul odor
    • Fever or chills
  • Severe trauma or physical injury
    • Hematoma
    • Skin under the toenail exposed
    • Visible bone parts.


These are the most common methods used for the diagnosis of the black toenail:


  • Medical history of the patients
    • Recent trauma or injury
    • Similar problems in the past
    • How long ago did the toenail turn black
    • Current and past treatments (including surgical interventions)
    • History of fungal infection
    • Family history (especially of melanoma or other forms of cancer)
  • Physical assessment of the feet (podiatrist’s office)
    • Open/closed fractures identification
    • Infection at the level of the toenail
    • Severity of injury and assessment of nail discoloration percentage
  • Nail biopsy
    • Often used for the confirmation of the diagnosis
    • Can either confirm the diagnosis of fungal infection or melanoma
    • Often performed at the same time with the removal of the nail.

Complications of a Black Toenail

Even though you might be tempted to delay going to the doctor, you have to understand that there are certain risks that come with taking this decision. In the situation that you have an injury or an infection, without treatment, you can suffer from severe complications.

One of the most common complications is the progression of the infection to the bone, a condition which is known as osteomyelitis. In the best of cases, this infection can be treated with powerful intravenous antibiotics, the treatment being administered for a long period of time. As for the worst case scenario, the doctor will have no other choice but to amputate the respective digit.


These are the most common measures of treatment undertaken for the black toenail:

  • Anti-fungal medication
    • Topical or oral administration (depending on the severity of the infection, the doctor might recommend both)
    • For the duration of the treatment, the patient is advised to maintain excellent hygiene measures (so as to ensure the efficacy of the treatment)
  • Nail drainage
    • The doctor will make a small cut at the level of the nail, so as to drain the pus accumulated under the nail bed (often times, the pus is mixed with blood)
    • After the nail drainage has been performed, the doctor will apply an antibiotic dressing, so as to avoid the risk of secondary bacterial infections
  • Surgical intervention
    • Nail removal + intervention for laceration and bone exposure (suturing)
    • Nail can be replaced on the nail bed (acting as a protective barrier and supporting the healing process)
    • Cautery procedure can also be used for the draining of the hematoma
    • Surgical removal of the nail/digit in case of cancer (may be accompanied by chemotherapy or radiation therapy).
  • Foot soaks
    • Lukewarm water + Epsom salt (equal quantities)
    • Frequency – two times per day
    • Duration of each foot soak – 15 minutes

Pictures of Black Toenail

black toenail pictures

black toenail pictures 2

black toenail pictures 3


It cannot be said with certainty that the affected toenail will regain its normal aspect and color. As for the recovery time, this is influenced by a number of factors, such as the severity of the trauma or the response to the prescribed treatment. In general, if there are no complications or associated problems, you can expect for your toenail to grow back and return to normal in a couple of months. Keep in mind that the toenails grow at a rate of approximately 3 mm per month.


There are certain measures that can be taken in order to prevent such problems:

  • Always wear comfortable shoes, avoiding those that are either too tight or ill-fitting
  • Make sure that you trim your toenails in an adequate manner (not too short or with cut corners)
  • Change your shoes on a daily basis (and your socks too)
  • Wear socks that are made from cotton (synthetic materials favor excessive perspiration, which in turn favors fungal infections)
  • Do not share objects of personal hygiene with other people (you cannot be certain who has a fungal infection and who is healthy)
  • Avoid walking barefooted around the swimming pool or in the public shower (risk of contracting a fungal infection)
  • Move any heavy objects with caution, so as not to incur any injuries or trauma
  • In the situation that you notice the first signs of a fungal infection, go to the doctor (the more you delay, the more the infection will evolve and it will be harder to get rid of it)
  • Avoid covering the black toenail with nail polish – this can aggravate the problem.

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