Juvenile and Adult Vaginitis

Vaginitis is defined as inflammation of the vaginal mucosa, which can occur in both juvenile (prepubertal) and adult female dogs and cats. In juvenile animals, it is often a self-limiting condition associated with hormonal immaturity and a lack of normal estrogenic stimulation, leading to a thin, atrophic vaginal epithelium that is more susceptible to bacterial overgrowth and inflammation. In adult animals, vaginitis is frequently secondary to underlying conditions such as urinary tract infections, foreign bodies, vaginal strictures or septa, neoplasia, or hormonal imbalances (e.g., hyperestrogenism). The condition is characterized by varying degrees of vaginal discharge, dysuria, and licking of the perineal area. In the context of the estrous cycle, vaginitis can occur during any stage, but it is particularly notable in juvenile animals before the first estrus, where it is termed 'juvenile vaginitis' or 'puppy vaginitis'. In adult animals, it may be associated with the proestrus or estrus stages due to increased vascularity and edema of the vaginal mucosa, which can predispose to secondary bacterial infections. The clinical significance of vaginitis lies in its potential to mimic more serious reproductive tract diseases, such as pyometra or metritis, and its impact on breeding soundness and fertility in adult animals.

The etiology of vaginitis is multifactorial. In juvenile animals, the primary cause is often a transient imbalance in the vaginal microflora due to low estrogen levels, which results in a lack of cornification of the vaginal epithelium and reduced local immunity. This allows commensal bacteria, such as Escherichia coli, Staphylococcus spp., Streptococcus spp., and Mycoplasma spp., to proliferate and cause inflammation. In adult animals, vaginitis can be caused by a variety of factors including: 1) Bacterial infections, often secondary to urinary tract infections (UTIs) or fecal contamination, with organisms such as E. coli, Proteus mirabilis, Klebsiella pneumoniae, and Enterococcus spp. being common isolates. 2) Viral agents, such as canine herpesvirus, which can cause vesicular lesions and vaginitis in adult dogs. 3) Foreign bodies, such as grass awns, foxtails, or retained tampons, which can cause mechanical irritation and secondary bacterial infection. 4) Anatomical abnormalities, including vaginal strictures, septa, or hypoplasia, which can lead to urine pooling or fecal contamination. 5) Neoplasia, such as leiomyoma, fibroma, or transmissible venereal tumor (TVT), which can cause inflammation and secondary infection. 6) Hormonal imbalances, including hyperestrogenism due to ovarian cysts or exogenous estrogen administration, which can lead to vaginal hyperplasia and inflammation. 7) Iatrogenic causes, such as improper vaginal examination or catheterization, which can traumatize the mucosa and introduce bacteria. 8) Allergic or irritant reactions to topical medications, shampoos, or environmental allergens. In cats, vaginitis is less common but can be associated with bacterial infections, viral infections (e.g., feline herpesvirus), or anatomical abnormalities.

Vaginitis is a common condition in both juvenile and adult female dogs, with a higher prevalence in prepubertal animals. Juvenile vaginitis is estimated to affect up to 10-20% of intact female puppies, typically between 6 weeks and 6 months of age, with no breed predilection, although some breeds such as Golden Retrievers and Labrador Retrievers may be overrepresented in some studies. The condition is usually self-limiting and resolves after the first estrus, when estrogen levels rise and the vaginal epithelium cornifies, providing a more resistant barrier. In adult dogs, vaginitis is less common and is often secondary to other reproductive or urinary tract diseases. It can occur in any breed, but brachycephalic breeds may be at higher risk due to anatomical factors such as a recessed vulva, which can lead to fecal contamination and urine pooling. In cats, vaginitis is rare, and when it occurs, it is often associated with viral infections or anatomical abnormalities. The incidence of vaginitis in breeding kennels may be higher due to increased stress, poor hygiene, and the presence of multiple animals, which can facilitate the spread of infectious agents. Additionally, intact females are more likely to develop vaginitis than spayed females, as the hormonal environment of the estrous cycle can influence the vaginal mucosa's susceptibility to infection. However, spayed females can also develop vaginitis, particularly if they have underlying urinary incontinence or anatomical abnormalities.

The pathophysiology of vaginitis involves a complex interplay between the vaginal mucosal barrier, the local immune system, and the presence of pathogenic microorganisms. In juvenile animals, low estrogen levels result in a thin, non-cornified vaginal epithelium with reduced glycogen content, which alters the normal acidic pH and reduces the number of lactobacilli that typically maintain a protective microflora. This allows opportunistic bacteria to adhere to the epithelium and proliferate, leading to an inflammatory response characterized by vasodilation, increased vascular permeability, and migration of neutrophils into the vaginal lumen. The inflammatory mediators released, such as prostaglandins and cytokines, further exacerbate the tissue damage and clinical signs. In adult animals, the pathophysiology is often similar, but the underlying cause may be different. For example, in cases of urinary tract infections, bacteria can ascend from the urethra into the vagina, causing inflammation. In cases of anatomical abnormalities, such as a recessed vulva or vaginal stricture, urine or feces can pool in the vaginal vestibule, creating a moist, nutrient-rich environment that promotes bacterial growth. In cases of hyperestrogenism, excessive estrogen stimulation can cause hyperplasia and edema of the vaginal mucosa, which can become necrotic and ulcerated, providing a portal of entry for bacteria. In cases of neoplasia, the tumor mass can cause mechanical irritation and obstruction, leading to secondary infection. The inflammatory response in vaginitis is typically characterized by an influx of neutrophils, which are visible on vaginal cytology, and may progress to a chronic inflammatory state if the underlying cause is not resolved. Chronic vaginitis can lead to fibrosis and scarring of the vaginal mucosa, which can further compromise the barrier function and lead to recurrent infections.

Several intrinsic and extrinsic factors predispose animals to vaginitis. Intrinsic factors include: 1) Age: Juvenile animals are particularly susceptible due to hormonal immaturity, while older animals may have decreased immune function. 2) Breed: Brachycephalic breeds with recessed vulvas are at higher risk due to anatomical factors. 3) Hormonal status: Intact females are more susceptible during proestrus and estrus due to increased vascularity and edema, while spayed females may have a higher risk if they develop urinary incontinence. 4) Anatomical abnormalities: Vaginal strictures, septa, or hypoplasia can predispose to urine pooling and fecal contamination. 5) Immunosuppression: Animals with concurrent diseases or those receiving immunosuppressive drugs are more susceptible to infections. 6) Obesity: Obese animals may have skin folds that trap moisture and bacteria, increasing the risk of vaginitis. Extrinsic factors include: 1) Poor hygiene: Inadequate cleaning of the perineal area can lead to fecal contamination. 2) Environmental stress: Overcrowding, poor ventilation, and high humidity in kennels can increase the risk of infectious vaginitis. 3) Improper breeding management: Breeding during the wrong stage of the estrous cycle can lead to trauma and infection. 4) Iatrogenic factors: Inappropriate use of vaginal catheters, improper examination techniques, or excessive douching can introduce bacteria or cause trauma. 5) Exogenous hormone administration: The use of estrogen or progesterone compounds for contraception or treatment of other conditions can alter the vaginal environment and predispose to infection.

The clinical signs of vaginitis vary depending on the severity and underlying cause. Common signs include: 1) Vaginal discharge: This is the most common sign, and the character of the discharge can vary from mucoid to purulent, and may be blood-tinged. In juvenile vaginitis, the discharge is often white or yellow and may be intermittent. In adult vaginitis, the discharge may be more copious and foul-smelling if a bacterial infection is present. 2) Licking of the perineal area: Animals may lick their vulva excessively due to irritation. 3) Dysuria: Inflammation of the vaginal mucosa can cause pain during urination, leading to frequent attempts to urinate or straining. 4) Pollakiuria: Increased frequency of urination may be observed. 5) Redness and swelling of the vulva: The vulva may appear erythematous and edematous. 6) Pain on palpation: The animal may show signs of discomfort when the perineal area is palpated. 7) In severe cases, systemic signs such as fever, lethargy, and anorexia may be present, especially if the infection has ascended to the uterus or urinary tract. 8) In breeding animals, vaginitis can lead to infertility or abortion if the infection spreads to the reproductive tract. It is important to note that some animals with vaginitis may be asymptomatic, and the condition is only detected during a routine examination or when investigating other reproductive issues.

The differential diagnoses for vaginitis include: 1) Urinary tract infection (UTI): Both conditions can present with dysuria and pollakiuria, but UTIs are characterized by the presence of bacteria and inflammatory cells in the urine, and may be associated with hematuria. Vaginal cytology and urine culture can help differentiate. 2) Pyometra: This is a uterine infection that can cause a purulent vaginal discharge, but it is typically associated with systemic signs such as fever, lethargy, and polyuria/polydipsia, and is more common in older intact females. Ultrasonography can reveal an enlarged, fluid-filled uterus. 3) Metritis: This is an infection of the uterine wall, usually occurring postpartum, and can cause a purulent discharge and systemic signs. 4) Vaginal foreign body: A foreign body such as a grass awn can cause a localized inflammation and discharge, and may be visible on vaginoscopy. 5) Vaginal neoplasia: Tumors such as leiomyoma or TVT can cause a bloody or mucoid discharge, and may be palpable or visible on vaginoscopy. 6) Vaginal stricture or septum: These anatomical abnormalities can cause urine pooling and secondary vaginitis, and are diagnosed by vaginoscopy or contrast radiography. 7) Hyperestrogenism: This condition, often due to ovarian cysts or exogenous estrogen, can cause vaginal hyperplasia and discharge, and is diagnosed by serum estrogen levels and ultrasonography of the ovaries. 8) Canine herpesvirus infection: This viral infection can cause vesicular lesions and vaginitis, and is diagnosed by PCR or serology. 9) Coagulopathies: Bleeding disorders can cause a bloody vaginal discharge, but are usually associated with other signs of bleeding. 10) Trauma: Vaginal trauma from mating or foreign bodies can cause discharge and inflammation.

The diagnostic approach to vaginitis should be systematic and include the following steps: 1) Signalment and history: Obtain a thorough history including age, reproductive status, onset and duration of clinical signs, and any previous treatments. 2) Physical examination: Perform a complete physical examination, with special attention to the perineal area, including inspection of the vulva and vaginal vestibule. 3) Vaginal examination: A digital vaginal examination may be performed in adult animals to assess for strictures, septa, or masses. In juvenile animals, this may be deferred due to the small size. 4) Vaginoscopy: This is a key diagnostic tool to visualize the vaginal mucosa, identify any lesions, foreign bodies, or anatomical abnormalities, and collect samples for cytology and culture. 5) Vaginal cytology: Collect a sample from the cranial vagina using a sterile swab or cytobrush, and evaluate for the presence of inflammatory cells, bacteria, and the stage of the estrous cycle (based on the percentage of superficial and cornified cells). 6) Urinalysis and urine culture: Rule out a concurrent urinary tract infection, as this is a common cause of vaginitis in adult animals. 7) Bacterial culture and sensitivity: If a bacterial infection is suspected, culture a vaginal swab to identify the causative organism and determine appropriate antibiotic therapy. 8) Blood work: A complete blood count and serum biochemistry may be indicated if systemic signs are present or if an underlying hormonal imbalance is suspected. 9) Hormonal assays: Measure serum progesterone and estrogen levels to assess the stage of the estrous cycle and rule out hyperestrogenism. 10) Imaging: Abdominal ultrasonography may be performed to evaluate the uterus and ovaries, especially if pyometra or ovarian cysts are suspected. 11) Biopsy: If a mass or chronic inflammation is present, a biopsy may be taken during vaginoscopy for histopathological examination.

Laboratory findings in vaginitis are variable and depend on the underlying cause. Hematology may reveal a normal leukogram in mild cases, but in severe bacterial infections, there may be a leukocytosis with a left shift and toxic neutrophils. Serum biochemistry is usually unremarkable, but if there is a concurrent urinary tract infection, there may be elevations in renal parameters (BUN, creatinine) or evidence of dehydration. Urinalysis may show hematuria, proteinuria, and the presence of bacteria and white blood cells if a UTI is present. Vaginal cytology is a critical diagnostic tool. In juvenile vaginitis, the cytology typically shows a predominance of parabasal and intermediate cells, with a low percentage of superficial cells, indicating a lack of estrogenic stimulation. There may be a moderate number of neutrophils and bacteria. In adult vaginitis, the cytology will reflect the stage of the estrous cycle. During proestrus and estrus, there will be a high percentage of superficial and cornified cells, while during diestrus and anestrus, there will be more parabasal and intermediate cells. The presence of neutrophils and bacteria, especially if they are intracellular, suggests an active infection. A bacterial culture of the vaginal swab can identify the causative organism, with E. coli being the most common isolate. Hormonal assays may show low estrogen levels in juvenile animals, while in adult animals with hyperestrogenism, estrogen levels may be elevated. Progesterone levels can help determine the stage of the cycle and rule out pregnancy or pyometra.

Imaging modalities are useful in the diagnostic workup of vaginitis, particularly to rule out underlying reproductive tract disease. Abdominal ultrasonography is the most commonly used imaging modality. In cases of vaginitis, the uterus and ovaries may appear normal, but ultrasonography can identify concurrent conditions such as pyometra (enlarged, fluid-filled uterus), ovarian cysts (anechoic structures in the ovaries), or vaginal masses. The vaginal wall may appear thickened or hyperechoic if there is significant inflammation. Radiography is less useful for evaluating the vagina, but it can be used to identify radiopaque foreign bodies or to assess the pelvic anatomy. Contrast radiography (vaginography) can be performed to evaluate the vaginal lumen for strictures, septa, or masses. This involves injecting a contrast agent into the vagina and taking radiographs. Vaginoscopy is an endoscopic technique that allows direct visualization of the vaginal mucosa. It is the most sensitive method for detecting mucosal lesions, foreign bodies, and anatomical abnormalities. During vaginoscopy, the vaginal mucosa may appear erythematous, edematous, or ulcerated, and there may be a purulent discharge. In cases of chronic vaginitis, the mucosa may appear thickened and fibrotic. CT and MRI are rarely needed but may be useful for evaluating complex anatomical abnormalities or neoplasia.

Vaginal cytology is a cornerstone of the diagnostic evaluation of vaginitis. The sample is obtained by gently inserting a sterile cotton swab or cytobrush into the cranial vagina and rolling it onto a glass slide. The slide is then stained with a Diff-Quik or Wright's stain. The cytological evaluation should include an assessment of the epithelial cell types, the presence of inflammatory cells, and the presence of bacteria. In juvenile vaginitis, the cytology typically shows a predominance of parabasal and intermediate cells, with a low percentage of superficial cells, indicating a lack of estrogenic stimulation. There may be a moderate number of neutrophils and bacteria. In adult vaginitis, the cytology will reflect the stage of the estrous cycle. During proestrus and estrus, there will be a high percentage of superficial and cornified cells, while during diestrus and anestrus, there will be more parabasal and intermediate cells. The presence of neutrophils and bacteria, especially if they are intracellular, suggests an active infection. Histopathology is rarely needed for the diagnosis of vaginitis, but it may be performed if a mass is present or if the condition is refractory to treatment. Biopsies can be taken during vaginoscopy using a biopsy forceps. Histopathological findings may include epithelial hyperplasia, ulceration, and infiltration of the submucosa with neutrophils, lymphocytes, and plasma cells. In chronic cases, there may be fibrosis and glandular hyperplasia. Special stains, such as Gram stain, can help identify the type of bacteria present.

The treatment of vaginitis depends on the underlying cause and the age of the animal. In juvenile vaginitis, the condition is often self-limiting and resolves after the first estrus. Therefore, treatment is primarily supportive and may include: 1) Cleaning the perineal area with a mild antiseptic solution (e.g., dilute chlorhexidine) to reduce irritation and secondary infection. 2) Topical antibiotic ointments or creams may be applied to the vulva, but systemic antibiotics are generally not recommended unless there is a confirmed bacterial infection with clinical signs. 3) In some cases, hormonal therapy with low-dose estrogen (e.g., diethylstilbestrol) has been used to promote cornification of the vaginal epithelium, but this is controversial and not routinely recommended due to potential side effects. In adult vaginitis, treatment is directed at the underlying cause. If a bacterial infection is confirmed, appropriate antibiotics should be administered based on culture and sensitivity results. Common antibiotics include amoxicillin-clavulanic acid (12.5-25 mg/kg PO q8-12h), cephalexin (22 mg/kg PO q8h), or enrofloxacin (5-10 mg/kg PO q12h). The duration of antibiotic therapy is typically 2-3 weeks. If a foreign body is present, it should be removed via vaginoscopy. If an anatomical abnormality such as a vaginal stricture or recessed vulva is identified, surgical correction may be necessary. In cases of hyperestrogenism, the underlying cause (e.g., ovarian cysts) should be treated, which may involve ovariohysterectomy. If a neoplastic mass is present, surgical excision is the treatment of choice. In addition to specific treatments, supportive care is important, including ensuring adequate hydration and nutrition, and preventing self-trauma by using an Elizabethan collar if necessary. In severe cases with systemic signs, hospitalization and intravenous fluids may be required.

The prognosis for vaginitis is generally excellent, especially in juvenile animals, where the condition typically resolves spontaneously after the first estrus. In adult animals, the prognosis depends on the underlying cause. If the cause is a simple bacterial infection that responds to appropriate antibiotic therapy, the prognosis is good. However, if the vaginitis is secondary to an anatomical abnormality or neoplasia, the prognosis is more guarded and depends on the success of surgical intervention. In cases of chronic vaginitis, there is a risk of recurrence, especially if the underlying cause is not fully resolved. For breeding animals, vaginitis can affect fertility if it leads to ascending infections of the reproductive tract, but with appropriate treatment, fertility is usually preserved. Negative prognostic indicators include the presence of systemic signs, the development of complications such as strictures or adhesions, and the presence of a neoplastic process. Overall, with proper diagnosis and treatment, the majority of animals with vaginitis have a favorable outcome.

Follow-up care for vaginitis is important to ensure resolution of the condition and to monitor for recurrence. In juvenile animals, a recheck examination may be recommended after the first estrus to confirm that the vaginitis has resolved. In adult animals, a recheck should be scheduled 2-4 weeks after the initiation of treatment to assess the response to therapy. This may include a repeat vaginal cytology and culture to ensure that the infection has cleared. If the vaginitis was secondary to an anatomical abnormality or neoplasia, follow-up imaging (e.g., ultrasonography or vaginoscopy) may be recommended to monitor for recurrence. In breeding animals, it is important to ensure that the vaginitis is fully resolved before breeding to prevent complications. This may involve performing a vaginal cytology during proestrus to confirm a normal estrous cycle. Additionally, if the vaginitis was associated with a urinary tract infection, a repeat urinalysis and culture should be performed to ensure that the UTI has resolved. Owners should be advised to monitor for any recurrence of clinical signs, such as vaginal discharge or excessive licking, and to seek veterinary attention if these occur. In cases of chronic or recurrent vaginitis, a more extensive diagnostic workup may be necessary to identify any underlying predisposing factors.

Clinical pearls: 1) Juvenile vaginitis is a common, self-limiting condition that typically resolves after the first estrus. Avoid unnecessary antibiotic treatment, as it may disrupt the normal vaginal flora. 2) In adult animals, always rule out a urinary tract infection, as it is a common cause of vaginitis. 3) Vaginal cytology is a quick and inexpensive tool to assess the stage of the estrous cycle and the presence of inflammation. 4) Vaginoscopy is essential for identifying foreign bodies, strictures, and masses that may not be palpable. 5) If a bacterial infection is confirmed, culture and sensitivity testing is crucial to guide antibiotic therapy, as many bacteria are resistant to commonly used antibiotics. Pitfalls: 1) Failing to perform a thorough diagnostic workup can lead to misdiagnosis and inappropriate treatment. 2) Overuse of systemic antibiotics in juvenile vaginitis can lead to antibiotic resistance and disruption of normal flora. 3) Ignoring the possibility of a concurrent urinary tract infection can result in recurrent vaginitis. 4) In breeding animals, failing to resolve vaginitis before breeding can lead to infertility or abortion. 5) In cases of chronic vaginitis, failing to identify and correct anatomical abnormalities can lead to persistent or recurrent disease.

The following are current drug protocols for the management of vaginitis, based on Plumb's Veterinary Drug Handbook and theriogenology guidelines. For bacterial vaginitis, antibiotics should be chosen based on culture and sensitivity. Common choices include: 1) Amoxicillin-clavulanic acid (Clavamox): 12.5-25 mg/kg PO q8-12h for 10-14 days. 2) Cephalexin: 22 mg/kg PO q8h for 10-14 days. 3) Enrofloxacin (Baytril): 5-10 mg/kg PO q12h for 10-14 days (use with caution in young animals due to cartilage effects). 4) Doxycycline: 5-10 mg/kg PO q12h for 10-14 days (effective against Mycoplasma and Chlamydia). For juvenile vaginitis, if treatment is deemed necessary, topical therapy may be preferred. This can include: 1) Chlorhexidine solution (0.05%) for cleaning the perineal area. 2) Topical antibiotic ointments such as neomycin-polymyxin-bacitracin, applied to the vulva q12h. In cases of hyperestrogenism, treatment may involve: 1) Ovariohysterectomy to remove the source of estrogen (e.g., ovarian cysts). 2) If surgery is not an option, a GnRH agonist such as deslorelin (4.7 mg implant SC) may be used to suppress ovarian function. For supportive care, anti-inflammatory drugs such as carprofen (2.2 mg/kg PO q12h) or meloxicam (0.1 mg/kg PO q24h) may be used to reduce inflammation and pain. However, these should be used with caution in animals with renal or hepatic disease. In cases of severe inflammation, a short course of corticosteroids (e.g., prednisone 0.5-1 mg/kg PO q24h) may be considered, but this should be avoided if an infectious cause is suspected.

The literature on vaginitis in dogs and cats is relatively limited, but several key studies and reviews provide guidance. A study by Johnston et al. (2001) in 'Canine and Feline Theriogenology' describes juvenile vaginitis as a common condition that resolves after the first estrus, and recommends conservative management. Another study by Kustritz (2006) in 'Clinical Canine and Feline Reproduction' emphasizes the importance of ruling out urinary tract infections in adult dogs with vaginitis. A retrospective study by Olson et al. (1985) found that E. coli was the most common bacterial isolate in cases of vaginitis, and that antibiotic therapy based on culture and sensitivity was effective. A more recent study by England and von Heimendahl (2010) in the 'BSAVA Manual of Small Animal Reproduction' provides a comprehensive overview of the diagnostic approach to vaginitis, including the use of vaginoscopy and cytology. The consensus among experts is that juvenile vaginitis should be managed conservatively, while adult vaginitis requires a thorough diagnostic workup to identify and treat the underlying cause. There is also evidence that anatomical abnormalities, such as a recessed vulva, are a significant risk factor for recurrent vaginitis, and surgical correction may be necessary. Overall, the evidence supports a systematic approach to diagnosis and treatment, with a focus on identifying and addressing the underlying cause to prevent recurrence.