Black Toenail Causes



We have them on our fingers and toes, what are they? Nails! Finger nails and toenails are only traits that are found on few mammals, including humans. Toenails are made up of a protective layer of tips called alpha keratin. This tip is made of protein that helps protect the toes from infections and other damage. Nail disease does exist so it is important that one helps keep their toenails as healthy as possible. There are six sections to a nail, both the fingers and toenails. These parts include: the matrix, proximal fold, cuticle, nail plate, hyponychium and nail bed. Each of these areas has their own way of functioning and role. For instance, the nail bed is the deepest layer of the nail plate and it is like the glue that holds everything together. While it may not come to mind at first, you have probably had at least a black toenail or two during your lifetime. Often, black toenails are the result of an unhappy injury to your toes, foot or nails.  


The visible result of a toenail injury is usually very clear. However, there are certain symptoms associated with a black toenail that is not caused by injury. Some of the signs to look for with a black toenail include but is not limited to the following: 

  • Redness 
  • Pain  
  • Discharge from nail 
  • Blackening or discoloration of the nail 
  • Smelly odor 
  • Partial or complete separation from the toenail 
  • Inflammation 
  • Discomfort 
  • Inability to walk  

Just because your toenail does not immediately appear black, it doesn’t mean that there is no issue. A black toenail can increase its color from red to purple to brown and then black. Keep an eye out of the discoloration of the nail and not because of nail polish.  


The cause of a black toenail can differ depending on many things. Here is a list of different causes of a black toenail.  

  • Injury or trauma- One of the main reasons for a toenail to turn black is because of an injury. The injury can be from a heavy object hitting the toes and/or foot, a sports injury or stubbing the toe in a door. The reason for the immediate black-looking toenail is because the blood vessels break and form underneath the nail bed. The easiest way to relieve the pain and help with the toenail discoloration is by applying an ice pack and popping blood bubble.  
  • Medical conditions- Underlying medical issues tend to become a concern when it comes to nail color disfiguration. Unfortunately, there are diseases that are associated with causing black toenails. Some of these diseases include: heart disease, anemia, diabetes and sometimes melanoma. The best way to treat black toenails because of these medical issues is by talking to your doctor. They will know exactly what to give their patients for the best results.  
  • Infections- Infections can cause different reactions from people, including black toenails. Fungal infections are one of the main causes of black toenails. When fungus gets under the nail bed, it can begin to cause a foul odor and a white/yellow discoloration of the nail. Overtime, this discoloration will begin to appear darker as the infection grows. Some of the leading causes of fungus infections as moist socks and shoes, ill-fitting shoes and showering barefoot in infected bathtub and showers.  


A podiatrist is the best type of doctor to visit when there are issues involving the foot. If there was a foot or toe injury, there is usually no test to confirm the reasons for a black toenail. On the contrary, if there has been no injury, a podiatrist will do a series of physical exams and take samples and blood work to determine the cause of the black toenail. Depending on the diagnosis and cause of the black toenail, the podiatrist will ensure you that the nail will fall off on its own or eventually grow out and need to be cut. Over-the-counter pain medication can be given to those who need it, especially if toe nail removal has occurred. 


  • Below is a list of things to help prevent the growth of black toenails. 
  • Wear the proper fitting shoes. 
  • Always keep your feet and toes clean  
  • Wear clean shoes and socks 
  • Wear shower shoes to decrease infections 
  • Do not walk barefoot