Vaginitis, by its simplest definition, is inflammation of the vagina. Vaginitis is not, however, a simple condition. Its pathophysiology is poorly understood, prohibiting our ability to treat it specifically. This article is a review of what we know about this common condition, with suggestions for diagnosis and treatment.
FORMS OF VAGINITIS
Two forms of vaginitis are recognized in dogs—juvenile, or puppy, vaginitis and adult-onset vaginitis.
Juvenile vaginitis is vaginal inflammation and associated clinical signs in bitches that have not yet undergone puberty. No breed predisposition has been reported. Most affected dogs show minimal or no clinical signs; scant mucoid discharge at the vulvar lips is most commonly described. Often this discharge is an incidental finding at a routine physical examination, seen as whitish-yellow discharge gluing together the vulvar lips. Some bitches may exude a large enough volume of discharge to be of concern to the owner, and some bitches may lick at the vulva.
Illustration by Joel and Sharon Harris
Adult-onset vaginitis is much more common in spayed bitches than in intact ones. The age at onset of clinical signs is variable, and no breed predisposition has been reported. In 80% to 90% of cases, the presenting complaint is mucoid to purulent vulvar discharge.1,2 The next most common presenting complaints are vulvar licking, pollakiuria, and urinary incontinence.2 Occasionally, dogs have clinical signs associated with a concurrent disease (e.g. diabetes mellitus or hepatic disease) that exacerbates the vaginitis.
Several physiologic and pathologic conditions in dogs may be evidenced by vulvar discharge and vulvar licking. Such physiologic conditions include estrus, whelping, and postpartum lochia. Such pathologic conditions may arise from the reproductive tract (e.g. ovarian remnant syndrome, pyometra or uterine stump pyometra, vaginitis, vaginal neoplasia, a vaginal foreign body such as a foxtail), the urinary tract (e.g. urinary incontinence, a urinary tract infection [UTI], urinary tract neoplasia), or a systemic condition (e.g. canine brucellosis, canine herpesvirus infection, a coagulopathy, atopy).
Diagnostic test are the same for juvenile and adult-onset vaginitis. These tests include a cytologic examination of vaginal epithelial cells and vaginal discharge, vaginal and urine bacterial cultures and antimicrobial sensitivity testing, urinalysis, a digital vaginal examination, and vaginoscopy (Figure 1). Juvenile dogs, who generally have mild, self-limiting vaginitis, may not require a complete work-up.
Figure 1. Diagnosing and Treating Canine Vaginitis
A cytologic examination of the vaginal epithelium in dogs with vaginitis reveals noncornified epithelial cells (Figure 2). Vaginal discharge usually appears mucoid to mucopurulent on cytologic examination. In a survey of 15 dogs with vaginitis, 33% had mucoid discharge, 20% had mucopurulent discharge, and 27% had purulent discharge.1 Occasionally, dogs with vaginal inflammation have no vulvar discharge.1,2 Rarely, the discharge is blood-tinged; however, true hemorrhagic discharge has not been described in dogs with uncomplicated vaginitis.1,2
Figure 2. Cytologic examination of a vaginal specimen from a dog with vaginitis reveals noncornified vaginal epithelial cells and polymorphonuclear cells (modified Wright's stain; 100X).