By Dr. Becker
Vaginitis is inflammation of the vagina. There are two types of canine vaginitis: juvenile or puppy vaginitis, and adult-onset vaginitis.
Juvenile vaginitis occurs in female puppies and dogs that have not reached puberty. Most dogs with this form of vaginitis have few if any symptoms. There might be a bit of whitish-yellow discharge from the vulva, and some dogs lick at the area.
Adult-onset vaginitis is much more common in spayed adult dogs than intact dogs. The most common symptom is vulvar discharge that can be mild or severe. Other symptoms include licking the vulva, frequent urination, urinary incontinence, and attraction of male dogs to the female dog. Sometimes a dog will have a secondary or even primary condition like diabetes or liver disease that makes the vaginitis worse.
Causes of Vaginitis
The most common cause of vaginitis is a bacterial urinary tract infection, which may or may not be the result of constriction of the vagina caused by a conformational abnormality.
If your dog has a bladder infection, the urine contains lots of bacteria. When the infected urine passes through the vagina, the bacteria can colonize the vagina, leading to inflammation and infection. So in essence, a urinary tract infection can lead to a secondary vaginal infection.
Another cause of vaginitis in dogs is the presence of urine on the vaginal mucosa, which has a caustic, irritating effect. Since all female dogs urinate by passing urine through the vagina, but not every dog gets vaginitis, it’s assumed there is something abnormal about the urine itself, such as a pH problem, urinary crystals, or a urinary outflow problem.
In dogs with urinary incontinence, there is chronic leaking of small amounts of urine from the bladder out of the body. The urine may be in contact with the vaginal lining much of the time and lead to urine scalding, tissue inflammation, and a secondary localized infection.
Vaginitis can also occur from bacteria, yeast and viruses that get transferred to the vagina when a dog cleans herself after pooping. The rectum and vagina are very close in proximity, and cross-contamination can occur through licking the area. Vaginal yeast infections can also occur in dogs who are on prolonged antibiotic therapy or are immunocompromised.
Other causes of the condition include viral infections (including the herpes virus), foreign bodies in the vagina, trauma to the vagina, vaginal abscesses or tumors, hyperplasia of the vagina, steroid therapy, and zinc poisoning.
Sometimes in vaginitis, there is inflammation without infection. There can be several causes for this, including sensitivity to a shampoo or other cleaning agent that’s irritating to the vulva. Topical irritation of the vulva from shampoos, detergents, cleaning agents, and other solutions can lead to secondary vaginitis. I actually know of some dog owners who insist on wiping their dog’s vulva after she urinates. The wiping action can induce vaginitis from the constant disinfecting of this very delicate area.
Female dogs with recessed vulvas can also have recurrent issues with vaginitis. When you look at a female dog from behind, you should be able to see the tip of her vulva hanging down – it’s shaped like an upside-down teardrop. Some dogs that have excessive perivulvar fat or a vulva that is tucked up high, which is called a hooded vulva, can have a predisposition to vaginitis because the surrounding skin creates a ripe environment for secondary yeast and bacterial infections.
Diagnosing Vaginitis in Dogs
Diagnostic tests for juvenile and adult-onset vaginitis are the same, and can include a cytologic examination of vaginal discharge and cells of the vagina, vaginal and urine bacterial culture and sensitivity tests, a urinalysis to check for pH issues and urinary crystals, and a manual vaginal exam. A vaginoscopy should also be performed, which involves passing a scope into the vagina to check for abnormalities such as a stricture (narrowing) of the vaginal vault or vaginal septa, which are walls of tissue within the vagina. A vaginoscopy can also assess discharge present in the vagina, vesicular lesions or lymphoid follicles, urine pooling, and polyps, cysts, masses or foreign objects in the vagina.
A blood chemistry profile, complete blood count and an electrolyte panel will also be run. If the dog has adult-onset vaginitis, she should be tested for canine brucellosis.
Sometimes x-rays are taken or an ultrasound is performed to look for tumors, foreign bodies, or bladder or tissue changes associated with the cervix or reproductive organs.
Dogs with juvenile or puppy vaginitis usually require no treatment because the condition almost always resolves spontaneously with the first heat. In dogs with vaginitis that will be spayed, it makes sense to wait until after the first estrous cycle to perform the procedure. I don’t recommend spaying puppies with recessed vulvas until they’ve had at least one estrous cycle, which usually completely eliminates the risk of vaginitis.
Treatment of adult-onset vaginitis depends on the cause. Appropriate antibiotic therapy (based on a culture and sensitivity test) will be given to resolve a bacterial infection in the urinary tract and/or the vagina. It is very important to treat the bacterial infection with the correct antibiotic. Indiscriminate use of antibiotics can promote the growth of additional types of bacteria in the vagina, and can actually exacerbate opportunistic yeast infections.
If the cause of the vaginitis is urinary incontinence, this condition must be treated first in order to resolve the vaginitis. Treatment for urine dribbling depends on the cause. In spayed female dogs, it is almost always hormone-related.
If there is systemic disease present such as diabetes or Cushing's, those conditions will require treatment to resolve the vaginitis or prevent a recurrence.
In all cases of vaginitis, I recommend a broad-spectrum non-diary probiotic be administered to help keep opportunistic bacteria levels in check. If a case of puppy vaginitis turns into a chronic case of adult vaginitis, immunoglobulin testing should be performed to check the dog’s innate immune function. Many dogs with IgA deficiency have recurrent opportunistic infections.
For more information: How to handle chronic vaginitis in veterinary patients.