A black toenail occurs due to bleeding or pigment changes beneath the nail plate. While often harmless, understanding its potential causes is important. Factors contributing to a toenail turning black and possibly detaching range from common injuries to less frequent underlying conditions.
Common Reasons for Black Toenails
The most frequent cause of a black toenail is trauma, medically known as a subungual hematoma. This occurs when blood vessels under the nail break, causing blood to pool and appear as a dark discoloration. Repetitive pressure from ill-fitting shoes during activities like running can cause this, as can dropping a heavy object on the toe or stubbing it. The pooled blood can create pressure and pain, and as the nail grows out, the discolored portion may eventually lift or fall off.
Fungal infections, or onychomycosis, are another common cause of toenail discoloration and detachment. These infections can cause the nail to turn dark brown, yellow, or black, and may also lead to thickening, brittleness, and a crumbly texture. As the infection progresses, it can cause the nail to detach from the nail bed.
Less common causes for a black toenail include certain medications, underlying medical conditions like psoriasis, diabetes, or circulatory problems, and, in rare instances, melanoma. Melanoma under the nail, known as subungual melanoma, appears as a brown or black streak that may increase in size over time and does not grow out with the nail. This condition can also cause the nail to separate from the nail bed, and the discoloration can extend to the surrounding skin.
When to See a Doctor
Seek medical attention for a black toenail in several situations. If you experience severe or increasing pain and swelling, especially if the pain feels throbbing, a doctor can assess the injury and potentially drain the accumulated blood to relieve pressure. Signs of infection, such as redness, warmth, pus draining from the area, or red streaks leading from the nail, also require prompt medical evaluation.
Consult a healthcare provider if the black discoloration appeared without obvious trauma or injury. Also, seek medical attention if the dark area is spreading, changing in size or color, or extends into the skin surrounding the nail. Individuals with underlying health conditions such as diabetes, a compromised immune system, or peripheral artery disease should have any toenail changes checked by a doctor, as these conditions can increase the risk of complications. If you are unsure about the cause of your black toenail or how to manage it, a medical professional can provide an accurate diagnosis and appropriate guidance.
Managing and Preventing Black Toenails
For black toenails resulting from trauma, home care involves resting the affected foot and elevating it to reduce swelling. Applying an ice pack wrapped in a cloth to the injured area can also alleviate pain and swelling. Keeping the area clean and dry, and covering it with a non-stick bandage, can protect the toe as the old nail falls off and a new one grows in its place, which can take several months. Avoid attempting to drain the blood yourself, as this can lead to infection or further damage.
Toenail fungal infections, or onychomycosis, require specific medical treatment. While some mild cases respond to over-the-counter antifungal creams or ointments, more persistent infections require prescription topical or oral antifungal medications. A doctor’s diagnosis confirms the type of infection and determines the most effective treatment plan, as some treatments can have side effects.
Preventing black toenails involves strategies related to footwear and foot hygiene.
- Wear well-fitting shoes with adequate toe room, especially during physical activities, to prevent repetitive trauma and pressure on the nails.
- Regularly trim toenails straight across and not too short to reduce the chance of them catching on shoes or sustaining injury.
- Maintain good foot hygiene by keeping feet clean and dry, and wear moisture-wicking socks to prevent fungal infections.
- Wear protective footwear in public areas like locker rooms and showers to reduce the risk of acquiring fungal infections.