Black toenail: Causes and treatment
Fungal infections of the toes are relatively treatable at home when caught early. Over-the-counter ointments, creams, and polishes are usually effective. Severe cases may require a prescription antifungal treatment.
Black Toenail
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What makes a toenail turn black?
Toenails are naturally white in color. Sometimes discolorations can occur from nail polish, nutritional deficiencies, infection, or trauma. Black toenails are attributed to a variety of causes, some of which resolve on their own. If your nail doesn’t get better, you’ll need to see your doctor to rule out a more serious cause of black toenail.
A black toenail may be caused by:
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- An underlying medical condition: This may include anemia, diabetes, heart disease, or kidney disease.
- Fungal infections: While these often look white or yellow, fungal infections can sometimes cause black toenails from debris buildup. Your toenails are especially vulnerable to fungal infections because they thrive on moist and warm environments.
- Melanoma: This is the most serious type of skin cancer, which often appears as a dark brown misshapen spot. Such spots can also occur underneath nail beds.
- Trauma: Usually caused by an injury, trauma to the toenail can cause the blood vessels beneath a nail to break. The resulting bleeding underneath the nail appears black.
A black toenail doesn’t necessarily require a doctor’s visit — the need for medical treatment depends on the initial cause. Knowing the cause can help you make this decision. On the flipside, if you don’t know the cause, it’s a good idea to see your doctor just in case your black toenail is a sign of a serious medical condition.
Not all cases of toenail fungus require a doctor’s visit. However, if you also have diabetes, you should see your doctor for treatment.
A dermatologist can also help diagnose and treat black toenail. You’ll need to see a dermatologist if you suspect melanoma. However, if your black toenail is caused by another underlying health issue, such as diabetes, then you’ll also need to see your primary doctor to treat the cause.
Any black toenail that doesn’t go away should be looked at by a doctor. If you’re concerned about your black toenail and don’t already have a dermatologist, you can view doctors in your area through the Healthline FindCare tool.
Toenail fungus that’s left untreated can spread throughout your feet and other parts of your body. It can also cause permanent nail damage.
Complications can also arise from melanoma in the toenail that’s mistaken for trauma-induced black toenail. It’s important to see your doctor if you notice any black spots that might be spreading throughout the nail, or if they don’t go away despite your toenail growing out.
Fungal infections of the toes are relatively treatable at home when caught early. Over-the-counter ointments, creams, and polishes are usually effective. Severe cases may require a prescription antifungal treatment.
If a black toenail is caused by an injury, the resulting spot from broken blood vessels will disappear once your nail grows out.
Black toenail caused by trauma from an injury usually resolves on its own without treatment. However, if your toenail grows out and it still appears black, then the symptoms might be related to another underlying cause.
Toenail discoloration related to diabetes and other health conditions requires treatment for the underlying causes.
Black toenail: Causes and treatment
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Medical News Today only shows you brands and products that we stand behind.
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- Fact-check all health claims: Do they align with the current body of scientific evidence?
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Black toenails can be unsightly and sometimes painful. While there are several potential causes of black toenails, many are easy to treat or may clear up on their own.
In this article, we look at six potential causes of a black toenail, in addition to treatment options and tips for prevention.
The cause of a black toenail may be benign or quite serious.
It is important for a person who develops a black toenail to understand some of the potential causes.
When in doubt, it is a good idea to be examined by a medical professional who can diagnose the problem and develop an effective treatment plan.
1. Repetitive trauma
When a person wears poorly-fitting shoes, they may be at risk of developing black toenails due to repetitive trauma.
Long-term pressure on the toes from poorly-fitting shoes can cause a range of problems, from small blisters to bloody blisters under the nail.
In mild cases, the black toenail will grow out naturally over time without treatment. In severe cases, such as when the nail begins to detach from the nail bed, a person should seek medical treatment.
2. Blunt force
In some cases, the trauma may be a one-time blunt-force injury, for example, if a person drops a heavy object on their foot or toes. When this happens, blood vessels in the nail bed break, causing blood to pool there.
The injured toe will start to hurt and pool blood beneath the skin almost immediately. The buildup of blood will cause the toe to feel painful and swollen. A doctor can treat this condition by draining the blood with a pinprick.
3. Fungal infections
Fungal infections are another common problem that can cause black toenails to form. Typically, a fungal infection causes a white or yellowish discoloration. However, debris can build up near the infection, causing the nail to appear black.
Toenails are particularly susceptible to fungal infections, as socks and shoes can provide a warm and moist breeding ground for a fungus to become established. Fungal infections can usually be prevented with proper foot care.
4. Melanoma
In rare cases, a black toenail may be caused by melanoma. Melanoma is the most aggressive form of skin cancer.
Melanoma causes the skin to develop one or more patches of dark, irregular-looking skin. In some cases, the patch of darkening skin grows beneath the nail bed.
Melanoma develops slowly, and without other symptoms, so it is often not noticed in the early stages, especially if it originates under the toenail.
5. Pigmentation changes
People’s skin tones can naturally change over time. For people with darker skin, a dark patch may develop beneath the toenails.
Pigmentation changes are usually uniform, so if it affects a toe on one foot, it will usually affect the matching toe on the other foot. The fingernails may develop darker patches beneath them as well.
6. Underlying conditions
There are a few medical conditions that may cause black toenails, including:
In most cases, controlling the underlying condition will help the nail to regain its original color.
