causes of black toenails
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).
Black Toenail â Causes, Treatment, and Prevention. Dr. Dr. 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.