In this month's Ask the Expert series, Chief Science Officer Beth DuPriest, PhD explains the difference between AV and DIV, and how these similarly diagnosed conditions differ from BV. Have a question about vaginal biome science? Submit yours here and your answer may be featured in an upcoming newsletter.
Q: What are AV and DIV? How are they different from BV?
A: Aerobic vaginitis (AV) is a dysbiotic inflammatory vaginal condition identified just 20 years ago1. It is often confused with bacterial vaginosis (BV) because symptoms are overlapping to some degree. Patients with BV typically report a whitish-gray thin vaginal discharge, often with an odor described as “fishy”. There may be some vaginal discomfort but it is usually not severe. In contrast, AV patients often have a copious thicker yellowish discharge with a strong, very unpleasant odor accompanied by moderate to severe discomfort, including vulvovaginal irritation and dyspareunia. In AV, as in BV, there is a reduction in number of vaginal lactobacilli, and an overgrowth of pathogenic organisms. In AV, however, these organisms typically include Escherichia coli, Streptococcus agalactiae (Group B Strep, GBS), Enterococcus faecalis, and Staphylococcus aureus which require treatment with different antibiotics than the anaerobes present in BV. GBS in particular is found in the vaginal fluid of healthy (asymptomatic) women with moderate frequency, and so AV – similar to BV – is not a condition with a single clear-cut cause, but rather a polymicrobial condition. AV benefits from testing to determine the causative microbe(s) in each case.
The name “AV” is supposed to reflect the metabolic function of the microbes involved, differentiating them from the anaerobes present in BV, but in reality, all of these organisms are facultative anaerobes / aerotolerant, as most BV organisms are; none is a true aerobic organism. The better differentiating factor with AV is the presence of leukocytes in vaginal fluid and symptoms of a true inflammatory state including edema and erythema of vulvovaginal tissues. BV is not considered an inflammatory condition because of the lack of leukocytes, edema, and erythema, though it is associated with alterations in certain immune markers. The antibiotic of choice for treatment of AV may depend on the organism present; kanamycin or quinolones are often selected because they have little effect on lactobacilli2. Anti-inflammatory topical steroids typically are also needed for full resolution of AV symptoms.
Desquamation of the vaginal epithelium is considered a distinguishing factor. In AV, superficial layers of vaginal epithelium are eroded so that intermediate and parabasal cells (the deeper layers of the stratified squamous epithelium comprising the vaginal lining) are observed in vaginal fluid smears or Pap tests. Often vaginal ulcerations or erosions are visible upon exam. When the desquamation is severe enough, the condition is labeled as desquamative inflammatory vaginitis (DIV). As such, DIV is an advanced form of AV. Some prefer to use the term DIV to encompass the entire range of AV/DIV conditions to avoid the misunderstanding arising from the use of the term “aerobic” and to emphasize the damage that is occurring at all stages of the condition.
Historically, BV has not been thought of as a desquamating condition. But it has recently been shown that women with BV – especially asymptomatic BV – also have desquamation and high levels of intermediate and parabasal cells in their vaginal fluid3, though visible erosions are not reported in BV. There have also been reports of vaginal fluid leukorrhea in BV. Thus, it is possible that the separation between DIV and BV is more artificial than we have previously thought, and perhaps there is a continuum of vaginal responses to various organisms or combinations of organisms. It seems likely that symptoms reported by a patient depend both on the species present and on a woman’s underlying immune system, and someday there may be diagnostics that will allow for more targeted therapies responding to these nuances.
There is much remaining to be learned about AV/DIV. For now, recognizing AV/DIV as a separate entity from BV is important to ensure proper treatment.
1. Donders GGG, Vereecken A, Bosmans E, Dekeersmaecker A, Salembier G, Spitz B. Definition of a type of abnormal vaginal flora that is distinct from bacterial vaginosis: aerobic vaginitis. BJOG Int J Obstet Gynaecol. 2002;109(1):34-43. doi:10.1111/j.1471-0528.2002.00432.x
2. Tempera G, Furneri PM. Management of aerobic vaginitis. Gynecol Obstet Invest. 2010;70(4):244-249. doi:10.1159/000314013
3. O’Hanlon DE, Gajer P, Brotman RM, Ravel J. Asymptomatic Bacterial Vaginosis Is Associated With Depletion of Mature Superficial Cells Shed From the Vaginal Epithelium. Front Cell Infect Microbiol. 2020;10:106. doi:10.3389/fcimb.2020.00106