A nail can turn black for various reasons. A shock, a fungal infection, or certain illnesses can explain this blackening, which is most often benign. Let’s review the different causes of black nails, as well as the associated solutions to restore even and healthy nails.
Black Nails: Possible Causes
Various causes can turn nails black. Shock and trauma are the most common, but fungal infections and melanoma are also possible.
Shock or repeated trauma to the nail
These are among the most common causes. The nail rests on the nail bed. This area is rich in blood vessels. Following a shock, these can rupture and begin to bleed. The black spot that appears under the nail is simply blood.
Generally, the shock that causes the bruise is severe and remains in the memory. This could be, for example, a hammer blow to the finger, a pinched nail in the door, or a heavy object hitting the toe.
This nail discoloration is also well known among runners, who after a long run may discover their toenails black: repeated micro-shocks against the tips of the shoes can cause it.
A fungal infection
Nail fungus is a common infection. Fungi colonize the nail and cause various symptoms on the fingernails or toenails. They include a change in nail color. Symptoms include:
- Nail discoloration: white, yellow, or a darker color than usual;
- Thickening and deformation of the nails;
- A weakened nail, which becomes more brittle and may peel off.
A fungal infection never heals spontaneously. It continues to progress and can spread to the skin or surrounding nails. This infection is also contagious: you can infect your loved ones. Therefore, action must be taken at the first symptoms to eliminate it.
More rarely, cancer
Subungual melanoma is a form of skin cancer that appears as a black spot under the nail. It often appears as a line running along the length of the nail.
Melanoma most often affects the thumbnail and big toenail. This disease remains rare: it is estimated to account for 2 to 8% of skin cancers. However, it must be treated without delay. As with all cancers, the spot is bound to spread without treatment and can eventually lead to metastases.
How to prevent nail trauma and the risk of fungal infections?
Injuries to the nail are not always easy to anticipate. They most often result from clumsiness or an accident. Remember to protect your hands during DIY or gardening sessions. Safety shoes may be useful if you handle heavy objects. Athletes should pay particular attention to their choice of footwear, especially their size. Shoes should be neither too tight nor too wide to prevent the foot from rolling forward during activity. In your spare time, don’t forget to use the foot spa kit to give your feet a complete foot massage.
Finally, to prevent fungal infections, remember to wear sandals in all humid areas: swimming pools, saunas, shared showers… all places that are favorite breeding grounds for fungi.
What treatment for a black toenail?
The treatment to adopt depends on what caused the black toenail: shock, fungal infection, or disease.
Treating a Black Nail Following an Impact
There are two possible scenarios for a hematoma under the nail.
- The hematoma is recent, large, and painful. It causes regular stabbing pains.
In this case, it is advisable to drain the blood to relieve the pressure under the nail. Take a previously disinfected paper clip. Unbend it and heat it with a lighter until the tip is red. Pierce the nail in the center of the hematoma. Repeat if necessary until the blood drains. Apply pressure to the nail to drain it completely. Disinfect the nail and protect it with a bandage to limit the risk of infection.
- The hematoma is painless: no special action is required. The stain will disappear on its own as the nail grows back. However, you’ll need to be patient: nails grow very slowly. It takes 3 to 6 months for fingernails to completely renew themselves, and 12 to 18 months for toenails.
How to treat a black nail after a fungal infection?
Fungus can usually be treated at home with suitable products, such as an anti-fungal nail treatment. There are different options: nail polish, serum, cream, or gel. All should be applied daily to destroy the fungus. These products are often based on tea tree, ciclopirox, or terbinafine, recognized antifungal active ingredients.
If the fungal infection does not resolve despite applying an antifungal serum or gel, or if you suffer from other health problems (diabetes, psoriasis, etc.), do not hesitate to consult a doctor.
