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Subungual Exostosis

This article does not constitute as medical advice.
If you are experiencing symptoms, contact your doctor or make an appointment.

What is a Subungual Exostosis?

 A subungual exostosis is a bony spur on the tip of the toenail resulting from trauma to the toenail. This condition can also occur on fingernails. Sometimes small benign tumors may also grow under the toenail or on other bones in the body. Nonetheless, this spur is relatively uncommon and can be removed by surgery. Learn more about this condition here:

Causes of Subungual Exostosis

The true cause of this condition is still unknown, but experts have estimated several factors that lead to these bone spurs, such as: 

  • Injury: Trauma to the toenail from a previous injury 
  • Irritation: Repetitive irritation to the area of the foot, such as tight shoes rubbing up against the toe or certain sports such as soccer or running. 
  • Infection: A fungus or parasite that has previously infected the toenail
  • Gender: Women are more likely than men to develop this condition

Symptoms of Subungual Exostosis

Patients can typically spot the deformity on their big toe, which is the telltale sign. If you notice this spur, contact your podiatrist, who can perform an x-ray and recommend treatment. 

  • Nail deformity: An elevated lesion (typically on the big toe) forms under the nailbed. The growth becomes bigger with time. Please view our photo below to see what subungual exostosis typically looks like. 
  • Discomfort: The patient will feel mostly asymptomatic at first. However, they may feel a progression to discomfort and pain if left untreated from the lesion separating the nailbed from the nail plate. 

Treating Subungual Exostosis

If you notice symptoms of this condition, make an appointment with your podiatrist to confirm the diagnosis and to recommend treatment. 

  • Diagnosis: Your podiatrist will perform an x-ray or biopsy to confirm the deformity’s origin. 
  • Surgery: Surgery may be required for this condition to remove the bony spur or tumor under the toenail. The surgeon will remove the lesion and scrape the bone clean in order to prevent future tumors. 
Subungual Exostosis

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