What you see. The starting point for addressing any equine health related issue is your observation.


Lump, Bump, Growth inside Nostril


Soft smooth swellings found on the outside wall of the nostril are fairly common. This is the location for the so called False Nostril Cyst or "atheroma", a benign growth filled with a cheesy thick fluid. As is true in any location though, a variety of other growths and swellings can occur here too, including tumors, abscesses, cysts, and granulomas - to name a few.

  • Code Yellow

    Contact Your Vet at Your Convenience for an Appointment
    • To ensure a correct diagnosis, have your vet examine the horse.

your role


What To Do

When assessing any swelling, carefully and gently feel its shape and consistency, and look for masses elsewhere. Take note of whether it seems painful to the touch, any break in the skin, and whether there is drainage. Consider how long it has been present and how quickly you think it has grown. Report this to your vet, or take a photo of it and share it with them.

What Not To Do

Do not attempt to "lance" a swelling here without veterinary guidance. The majority of growths here will recur without proper treatment.

your vet's role

Diagnosis of False Nostril Cyst is quite straightforward, based on the characteristics of the swelling and the location, and it is usually quite treatable. If the mass does not look like to them like a typical atheroma, your vet may choose instead to aspirate or biopsy it.
Questions Your Vet Might Ask:
  • How old is the horse?
  • When did you first notice this problem?
  • Can you send a photo?
  • Describe the swelling?
  • What are the results of the Whole Horse Exam (WHE)?

Author: Doug Thal DVM Dipl. ABVP