Black Toenail Causes

Black toenail, also known as subungual hematoma, is a common condition where blood collects underneath the toenail, resulting in a dark, blackish discoloration of the nail. It typically occurs due to trauma or injury to the nail or toe.

Some common causes of black toenail include:

1. Stubbing or jamming the toe: Trauma from accidentally hitting or stubbing the toe can cause blood vessels under the nail to rupture and bleed, resulting in a blackened appearance.
2. Repetitive pressure or friction: Activities that involve repetitive pressure or friction on the toes, such as running, hiking, or wearing ill-fitting shoes, can lead to black toenails.
3. Running downhill: Long-distance runners, especially when running downhill, may experience black toenails due to the continuous impact and pressure placed on the toes.
4. Footwear issues: Wearing shoes that are too tight or small can cause the toes to rub against the inside of the shoe, leading to black toenails in some cases.
5. Fungal infections: In some instances, a fungal infection (such as onychomycosis) may cause the toenail to become discolored, including turning black. However, this is less common than trauma-related black toenails.

It’s important to note that while black toenails are generally harmless and resolve on their own, it’s advisable to consult a healthcare professional if there is severe pain, signs of infection (such as redness or swelling), or if the discoloration persists or spreads to other nails.