Black toenails are known among runner athletes, but there are other causes that cause them. Although many times they can be resolved at home, it is indicated to consult with a professional. Let’s see in this article how they originate and how they are treated.
Black toenails are not rare. In some groups of people, they are more frequent than in others and the situation is even familiar. This also leads to applying homemade solutions that are not always the ones indicated.
A group of people who know first hand the black toenails are the runners. In the practice of running sports, it is very common to appear dark coloration on the nails.
Among the runners, the most affected are marathoners and mountain trail athletes. The first for the long distances they must travel and the second for the uneven terrain in which they carry out their activity.
As we will see later, there is a risk factor among brokers. Both the repetition of impacts and irregularities of the terrain that alter the tread are causing a subungual hematoma.
A subungual hematoma is a technical name that black toenails receive in medicine. Precisely, it is a collection of blood that is located in the nail bed. 
It is not a clinical condition of severity rarely. It does not even represent an urgent vital risk when the cause is a melanoma. However, if accompanied by severe pain, it may be incapacitating to step on.
Causes of black toenails
Black toenails have their main origin in small repetitive trauma. But this is not the only cause. Let’s see below the most frequent situations that originate from them.
This is the main cause. If our toes are repeatedly traumatized, with constant rhythm for a long time, then subungual hematoma may appear. This is the reason for its prevalence among runners. The pounding of the toe against the inside of the shoe is the explanation.
A mild, small, painless bruise or a large bruise with disabling pain can be generated. In severe cases, the blood overflows the nail bed and goes outside under the nail.
It does not always happen, but it can be accompanied by an infection in the skin surrounding the nail. The signs are inflammation and red coloration that the nail surroundings take.
A curious and striking fact, which is the cause of subungual trauma hematoma, is the overlapping fingers. In people who have birth-bound fingers, friction is capable of leading to the production of the black nail.
Unlike continuous trauma, the accident is a unique and timely fact. For example, the fall of a blunt object on the foot. If the fall hits a nail it can break the blood vessels from producing the bruise.
The most common fungal infection in the feet is the well-known athlete’s foot. Although its presentation area is classically between the fingers, it can extend to the nails. In addition to changing the color of the nail towards green and yellow hues, fungi sometimes give black color. This may be due to the manufacture of a bruise or a mere change in pigmentation.
The most serious and dangerous form of black toenails is subungual melanoma. It is a variety of skin cancer that grows in the nail bed.
Of the total melanomas that human beings suffer, the subungual variety is approximately 5%. More than half of those that appear in the hand is located on the thumb, and almost nine out of ten of those that appear on the foot area on the first finger as well.
How to treat black toenails
The treatment of black toenails ranges between simple shapes and more complex variants. As we already anticipated, among the runners, usually, they resort to homemade approach methods to drain the blood under the nail.
And when subungual hematoma comes from trauma, the indication is drainage. If the blood protrudes outside the limits of the nail, what is done is a puncture to escape the blood.
If there is no access through the skin, the drainage should be through the nail. It would be necessary to drill the hard part of the nail to generate the escape route. It is no longer possible to be done at home and you have to turn to doctors or podiatrists.
In case of not draining the hematoma will continue its course, the nail will take off under pressure and it will be lost. Instead, a new nail will begin to grow to replace it. It is not dangerous for that to happen, only it will take months to complete the process.
For fungal infections, antifungals are chosen. Creams for athlete’s foot do not penetrate the nail, so lacquer presentations are preferred. If that first line fails, the next option is an oral medication.
The Bottom Line
Finally, before a subungual melanoma, the treatment is surgery. The entire nail should be removed and the tumor removed with the free margins to ensure healing. Of course, it is a practice that can only be performed by a surgeon and by no means practiced at home.