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


Swelling of Lip, Muzzle or Nose


Swelling of this area is fairly common, as it is frequently traumatized. It is one of the most common locations for pit viper (rattlesnake and similar) snake bite. Infectious diseases like Vesicular Stomatitis also affect the area. Contact irritation or allergy can be seen here to various feeds. Feed material that becomes embedded in the lips can cause abscess formation, and swelling of the lip or muzzle. A gray horse may have melanoma in the corner of the mouth and on the lips. This appears as a hard, non-painful thickening of the lips.

This is a sensitive area that can be difficult to examine, particularly when it is severely inflamed. Luckily, once the primary disease process is identified and treated, the area usually heals rapidly thanks to an excellent blood supply.

  • Code Red

    Call Your Vet Immediately, Even Outside Business Hours
    • If this problem seems severe and has come on suddenly.
    • If the results of the Whole Horse Exam (WHE) in the resting horse indicate fever (Temp >101F/38.3C) or heart rate greater than 48 BPM.
  • Code Yellow

    Contact Your Vet at Your Convenience for an Appointment
    • If the problem is very mild and does not seem to be causing much harm to the horse.
    • If the results of the Whole Horse Exam (WHE) suggest the horse is otherwise normal.

your role


What To Do

Assess your horse's general health using the Whole Horse Exam (WHE), paying particular attention to rectal temperature, heart rate and general attitude and appetite. Look for other areas of swelling. Put on gloves and assess the area, gently feeling for foreign material and areas of accentuated pain. Gently lift the lip and inspect its inside surface for wounds or foreign material.

Contact your vet with your findings and concerns.

your vet's role

Your vet assesses this area using careful examination, trying to determine a cause for the swelling. They determine body-wide health through physical examination. In rare cases, I have used ultrasound to visualize a thorn or porcupine quill embedded deep in the tissues of the muzzle.
Questions Your Vet Might Ask:
  • Do you notice anything that might be irritating this area?
  • Do you notice anything else abnormal?
  • Is there a wound in the area?
  • Do you see signs of swelling anywhere else?
  • What is the horse's age, sex, breed and history?
  • Do you notice other masses or swellings?
  • Is the swelling soft and fluidy-feeling or firm?
  • Does the area seem painful when pressure is applied to it?
  • What are the results of the Whole Horse Exam (WHE)?

Diagnoses Your Vet May Consider

The cause of the problem. These are conditions or ailments that are the cause of the observations you make.

Very Common
Less Common
more diagnoses

Author: Doug Thal DVM Dipl. ABVP