Out-of-place Urethral Lining in Dogs


PetMD Editorial

Updated Aug. 16, 2022

Urethral Prolapse in Dogs

Urethral prolapse is a condition where the urethra's mucosal lining (the mucus-producing lining of the canal that carries urine out of the bladder) falls out of place, often moving to the outer portion of the urethra, vaginal, or penile opening, making it visible.

Urethral prolapse can affect several other parts of a dog's body, including the urinary bladder (the storage sac for urine), the urinary tract, reproductive organs, and the immune system.

In many instances, no specific treatment is required unless there is a more serious underlying medical condition, or in the event of an infection.

Urethral prolapse can affect both dogs and cats. If you would like to learn how this condition affects cats, please visit this page in the PetMD health library.


Symptoms and Types

A prolapsed urethra often looks similar to a pea-sized mass, and may be red or purple in color. This can often be observed as a small mass of tissue on the end of the penis (or in a female, protruding from the urethral tract).

If the dog excessively licks the mass, it can become enlarged or inflamed. In some cases, the protrusion can bleed on or around the urethral opening. Dogs with urethral prolapse usually have difficulties urinating.


Sexual excitement may cause the mass to develop, as does inner abdominal pressure. Other possible causes include:

  • Testicular disease
  • Urethral diseases
  • Fractures of the penis
  • Abnormal anatomical development
  • Irritation due to sexual activity

And while it can occur in any breed, Boston Terriers and Bulldogs seem to be especially prone to this medical condition.


X-rays and other types of diagnostic imaging, such as magnetic resonance imaging (MRI) and computerized axial tomography scans (CAT) are often used to rule out any underlying issues with the prostate or bladder. Upon examination, your veterinarian will also need to rule out other common underlying causes, including fractures of the penis and urethral and testicular diseases.

Because some issues are only present during ejaculation, your veterinarian may find this action helpful for examining the body's genital functioning.


If there is inflammation or risk for infection, antibiotics are often prescribed prophylactically (preventively). In cases of extensive bleeding or pain, surgery will generally be recommended, but in many instances there is no need for treatment. Slowing your dog's physical activity to allow time for rest and healing is generally all that is required for the condition to pass.

Living and Management

The risk of recurrence is fairly high, so it is important for you to observe any physical changes to the dog's genital area.



Unfortunately, there are no preventive measures for urethral prolapse. If a dog shows a high likelihood of recurrence, neutering the animal may be your best option.

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