Black toenails are usually the result of toenail injury. However, there are other things that can cause a black toenail, including fungal or bacterial infections. Most cases of black toenails aren’t ...

Trauma or injury commonly causes a black toenail due to bleeding under the nail. Repetitive sports activities can lead to runner's toe, causing the toenail to turn black. Malignant melanoma, a serious ...

When Maria Delgado noticed a dark streak under her big toenail, she assumed it was from dropping her gym bag on her foot. Six months later, that seemingly innocent mark led to a diagnosis that saved ...

Discover the common nail and skin woes of runners and how nail professionals can tackle them... “Runners can be prone to a ...

Tucked inside their favorite pair of running shoes you’ll find what runners consider both a disgusting side effect of the sport and a badge of honor: bruised, black toenails (if the nail is still even ...