There are many causes of black or dark toenails but the most common is trauma. This discoloration, is called a ‘subungual hematoma’ referring to the blood that collects beneath the nail. This not only causes the nail to become discoloured, it also creates a tremendous amount of pressure, leading to intense pain
In many cases, medical treatment is advised to relieve this discomfort
Although everyone is susceptible to black toenails through accidental trauma, athletes and those who often walk barefoot are at higher risk. Black toenails are also common in immuno-compromised patients.