What does black under toenails mean?

Hello Anonymous,

Welcome to EmpowHER. You are a good friend, but the best way to help is to suggest that person schedule an appointment with a primary care physician, who will know that person's medical history, any prescribed medications and can look at the nails.

There are many causes of black or dark toenails, but the most common cause is trauma. When trauma occurs to a nail resulting in discoloration it is referred to as a subungual hematoma, which simply means there is a collection of blood underneath the nail.

Black toenails can be caused by a fungal infection, which is common in immuno-compromised patients, or they may indicate underlying melanoma (a malignant tumor consisting of dark-pigmented cells called melanocytes).

Regards,
Maryann