Vaginal Hyperplasia in Dogs

Dog and puppy

Imagine suddenly discovering a large mass of tissue protruding from your dog’s vulva. It may look like a tumor or an impending prolapse and can be very unsightly and unpleasant to see. I have had a number of dog guardians rush their dog in believing that somehow the dog was having a miscarriage. In reality though what they are likely seeing is called vaginal hyperplasia.

In vaginal hyperplasia, a proliferation of the vaginal mucosa, usually originating from the floor of the vagina near the front of the urethral opening, occurs during or just prior to the dog being “in heat;” it's a result of estrogenic stimulation. The most common sign of this condition is a mass protruding from the vulva. Initially, the surface is smooth and glistening, but with prolonged exposure it becomes dry and fissures develop. A slight vaginal discharge may be present. Vaginal hyperplasia interferes with copulation and reluctance to breed may be the only symptom. Occasionally, the prolapse continues throughout pregnancy or recurs at the delivery of puppies1.

Some affected dogs will exhibit straining or painful urination but it is rare that the dog will be void of any symptoms.

How common is vaginal hyperplasia?
Some breeds are more prone to vaginal hyperplasia including Boxers, Mastiffs, German Shepherds, Weimeraners, Labrador Retrievers and English Bulldogs among others2.

Symptoms of vaginal hyperplasia
The most common sign is the protrusion of pink, inflamed tissue from the vulva of the affected dog. The inflammation may result in pain and subsequent excessive licking of the area.

Treatment of vaginal hyperplasia
Unless the condition is extreme, it will generally resolve on its own as the dog's cycle progresses. Treatment generally requires only gentle cleaning and application of an ointment to sooth and protect the tissue. It is important to prevent further trauma and licking so an Elizabethan collar or diaper may be needed in severe cases.

Surgery can be applied but should be avoided if at all possible.

Prognosis for vaginal hyperplasia
In most cases the prognosis is good, although the condition may reoccur with future cycles.

Prevention of vaginal hyperplasia
Since the condition is associated with the estrus or heat cycle the only means of prevention is elimination of the cycle by spaying.

Questions to ask your veterinarian

  • My dog is in heat and has a large mass of tissue protruding from her vulva. What could it be?
  • Can she still urinate?
  • Can it be prevented?

If you have any questions or concerns, you should always visit or call your veterinarian -- they are your best resource to ensure the health and well-being of your pets. 


  1. "Vaginal Hyperplasia in Small Animals." Merck Veterinary Manual. Web.
  2. "Vaginal Prolapse in Dogs." Web.


Reviewed on: 
Sunday, February 8, 2015