Cytolytic vaginosis

What is cytolytic vaginosis?

Cytolytic vaginosis is a vaginal condition resulting from an overgrowth of lactobacilli. It may lead to symptoms such as vulvovaginal itching (pruritus), abnormal vaginal discharge, pain during urination (dysuria), and/or painful sexual intercourse (dyspareunia). These symptoms often intensify during the second phase of the menstrual cycle, known as the luteal phase.

Cytolytic vaginosis may also be referred to as Lactobacillus overgrowth syndrome and Doderlein’s cytolysis. The term cytolytic vaginosis is preferred as only a few species of lactobacilli are classified as Doderlein’s bacilli.

Cytolytic vaginosis is a less researched condition with conflicting views regarding its existence as a specific diagnosis.

Who gets cytolytic vaginosis?

The reported prevalence of cytolytic vaginosis ranges from 1.7–26.7%. It has been proposed that cytolytic vaginosis is not uncommon, and the lower reported prevalence could be attributed to misdiagnosis. This is likely due to its similarities in presentation to vulvovaginal candidiasis.

Cytolytic vaginosis is predominantly seen in women of reproductive age. It has been associated with various factors, including:

• The second phase of the menstrual cycle (luteal phase)
• Pregnancy
• Perimenopause
• Diabetes mellitus.

What causes cytolytic vaginosis?

Cytolytic vaginosis occurs when there is an overgrowth of Lactobacillus species in the vagina. Lactobacilli are the most prevalent microorganisms in the vaginal microbiome, with approximately 5 lactobacilli per 10 squamous cells. They play a critical role in maintaining a healthy vaginal environment through several mechanisms:

• Competing for nutrients
  • Lactobacilli block Candida species from adhering to vaginal epithelial cells and compete for nutrients, helping to prevent yeast overgrowth.
• Maintaining an optimal vaginal pH of 4–4.5
  • Under the influence of oestrogen, glycogen is deposited in the vaginal epithelial cells and metabolised into glucose. Lactobacilli then convert glucose into lactic acid, which helps maintain an acidic pH, inhibiting the growth of other pathogens.
• Producing antimicrobial substances
  • Lactobacilli produce bacteriocins and hydrogen peroxide, which inhibit the growth of other microorganisms.

When there is an overgrowth of lactobacilli, however, it can lead to excess lactate production in the vaginal environment. This hyperacidity can damage the vaginal epithelium, resulting in the lysis of vaginal epithelial cells characteristically seen with cytolytic vaginosis. Clinically, this lysis may manifest as symptoms such as increased vaginal discharge (due to shedding of the damaged or fragmented epithelial cells alongside normal vaginal secretions); and on wet smear can be observed as bare nuclei and cytoplasmic debris.

While the exact mechanisms behind the overgrowth of lactobacilli remain unclear, proposed factors include:

• Progesterone, as cytolytic vaginosis is more commonly seen during pregnancy, perimenopause, and the luteal phase of the menstrual cycle
• Diabetes mellitus, as it has been suggested that lactobacilli thrive with high serum glucose levels.

What are the clinical features of cytolytic vaginosis?

Many women with findings suggestive of cytolytic vaginosis on a vaginal swab or cervical smear have no symptoms. Affected women may report:

• Vulvovaginal itching (pruritus) or burning
• Discomfort with passing urine (dysuria)
• Pain during penetrative sexual intercourse (dyspareunia)
• Increased vaginal discharge — usually whitish and odourless; may be thin and watery or thick and curd-like
• Vulvar erythema, oedema, and excoriations
• Cyclical increase in symptoms during the luteal phase.

What are the complications of cytolytic vaginosis?

Cytolytic vaginosis that persists due to being untreated or misdiagnosed can lead to psychological distress and significantly affect self-esteem and sexual wellbeing.

How is cytolytic vaginosis diagnosed?

It is difficult to clinically differentiate cytolytic vaginosis from other causes of abnormal vaginal discharge, especially vulvovaginal candidiasis. In patients with persistent vaginal symptoms despite treatment for other suspected causes, cytolytic vaginosis should be considered.

Cibley and Cibley et al (1991) proposed the following diagnostic criteria for cytolytic vaginosis:

• High clinical suspicion
• Vaginal discharge with a pH between 3.5 and 4.5
• Wet smear findings:
  • Absence of Trichomonas, Gardnerella, and Candida
  • Abundant lactobacilli
  • Paucity of white blood cells
  • Evidence of cytolysis: bare or naked intermediate epithelial cell nuclei.

What is the differential diagnosis for cytolytic vaginosis?

Other conditions may mimic cytolytic vaginosis — differentiating features include:

• Vulvovaginal candidiasis
  • pH usually 4.5
  • Wet mount: hyphae / pseudohyphae / spores
• Bacterial vaginosis
  • pH usually >4.5
  • Whiff test positive: fishy odor when adding a drop of 10% potassium hydroxide to vaginal discharge
  • Wet mount: ‘clue cells’ (epithelial cells with borders obscured by small, anaerobic bacilli)
• Trichomoniasis
  • pH usually >4.5, although can be normal
  • Wet mount: motile trichomonas, abundant white blood cells.

Sexually transmitted infections (STIs), pelvic inflammatory disease (PID), and pregnancy risk should be considered in all patients presenting with abnormal vaginal discharge.

What is the treatment for cytolytic vaginosis?

General measures

• Use pads instead of tampons during menstruation — as menstrual flow is alkaline, raising the vaginal pH and inhibiting the growth of lactobacilli.
• Avoid sexual intercourse until symptoms resolve.
• Avoid tight clothing.
• Avoid using soap to wash the vaginal area. Wash with just water instead.
• Avoid scented vaginal products.
• Wear cotton underwear.

Specific measures

No specific treatment is necessary in asymptomatic patients. If a patient has been started on an antifungal for presumed vulvovaginal candidiasis, it should be discontinued.

Management of symptomatic cytolytic vaginosis aims to increase (alkalinise) the vaginal pH to discourage the growth of lactobacilli. Suggested treatment options include:

• Baking soda douche
  • Dissolve 30–60g baking soda (sodium bicarbonate) in 1 litre of warm water, and douche 2–3 times per week, then as required.
• Baking soda vaginal suppository
  • Fill empty gelatin capsules with baking soda. Insert 1 capsule intravaginally twice a week for 2 weeks.
• Baking soda sitz bath
  • Dissolve 2–4 tablespoons of baking soda in a 5 cm deep warm bath. Soak for 15 to 20 minutes, 2–3 times in the first week, then once or twice per week as required.

Re-evaluate if symptoms persist 2–3 weeks after starting treatment.

What is the outlook for cytolytic vaginosis?

Cytolytic vaginosis symptoms can be relieved with vaginal alkalising measures, although it may recur and can flare up cyclically in the luteal phase. Misdiagnosis may also prolong the disease course.

Further research is needed to improve our understanding around this condition, which is debated as a specific diagnosis.