Subungual Exostosis

Subungual Exostosis

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What is a Subungual Exostosis? Here are some facts about this condition


A Subungual Exostosis is a bony projection which can arise underneath the toenail. They generally are a result of some form of trauma to the toe that results in the formation of bony 🦴 irregularity or prominence. This condition usually affects teenagers and young adults.  Moreover, females are more likely to have this condition.

In addition, the exposed exostosis may take different forms. It may also present as a mass on the nail bed: smooth and dome shaped, white or red, hemorrhagic or verrucous. Various nail deformities result, depending on the location and the size of the tumor. Onycholysis, paronychia and ingrown nail are common. And due to varied clinical presentations, imaging is needed to make the diagnosis.

Causes of Subungual Exostosis

The cause of Subungual Exostosis is unclear. However, it occurs as a reaction to:
– Constant irritation
– Previous Trauma
– Chronic Infection
– Inherited conditions such as multiple Exostoses Syndrome

Symptoms of Subungual Exostosis

– Exostosis then grows gradually over weeks and months
– It also presents as a hard painful swelling under or beside the toenail, usually on its inner side.
– As it grows it presses against the nail, causing pain, which may be confined to the nail fold.
– With further growth, it separates the nail form the nail bed and erodes the overlying skin (making it prone to infections).

Treatment for Subungual Exostosis

  • High box shoe
  • Nail plate trimming/avulsion
  • Surgical exostectomy with nail bed repair
  • Direct access through the nail bed/nail bed reconstruction
  • Indirect access through a fish-mouth incision

In addition, subungual exostosis diagnosis is often delayed. It can present with various nail deformities (such as onycholysis, onychocryptosis or paronychia) that can impede the accurate diagnosis.

Are you suffering from this condition? One of our podiatrist can assist and recommend what treatment options are best to get you back on track.
Schedule an appointment here or you may call us at 44 (0) 207 101 4000. 📞



We hope you have a feetastic day! 👣☀️

-The Chelsea Clinic and Team




Check our latest blog about Curly Toes here ‎

Check our blog about Turf Toe here

Read our blog about Bunion here

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