Aerobic vaginitis (AV) is a vaginal infection marked by significant inflammation. This condition arises from an imbalance in the vaginal microbiome, where the population of protective bacteria decreases, allowing for an overgrowth of aerobic bacteria—microorganisms that need oxygen to thrive. It is a distinct form of vaginal dysbiosis, meaning it involves a disturbance in the natural microbial environment of the vagina. This disruption leads to a variety of uncomfortable symptoms and requires specific medical diagnosis and treatment to resolve.
Symptoms and Causes of Aerobic Vaginitis
The symptoms of aerobic vaginitis can cause considerable discomfort. Women with AV typically experience a sticky vaginal discharge that is yellowish or greenish and may have a foul or “rotten” smell. This is accompanied by significant vaginal inflammation, causing the vaginal walls to appear red, swollen, and irritated. Many also report a persistent burning sensation during urination and pain during sexual intercourse (dyspareunia).
The root cause of aerobic vaginitis is a shift in the vaginal ecosystem. A healthy vagina is dominated by Lactobacillus bacteria, which maintain an acidic environment that prevents harmful microbes from growing. AV occurs when these protective lactobacilli are depleted and replaced by an overgrowth of aerobic bacteria, which can be introduced from fecal, skin, or bladder sources. Common culprits include:
- E. coli
- Staphylococcus aureus
- Group B streptococci
- Enterococcus faecalis
This microbial imbalance is a disruption of the natural vaginal flora, not a sexually transmitted infection. Certain factors can increase the risk of developing AV. These include low estrogen levels during menopause, and hygiene practices like douching or using harsh soaps that disturb the natural pH of the vagina. Unprotected sexual activity can also introduce or spread the bacteria that lead to this condition.
Distinguishing Aerobic Vaginitis from Other Conditions
Aerobic vaginitis is frequently confused with bacterial vaginosis (BV), but there are clear differences. The primary distinction is the type of bacteria involved; AV is caused by aerobic bacteria (requiring oxygen), while BV is caused by anaerobic bacteria (flourishing in oxygen-poor environments). A feature of AV is significant inflammation, resulting in redness and swelling, which is minimal or absent in BV.
The symptoms also provide contrasting points. AV is characterized by a yellowish or greenish, often thick discharge with a foul odor. In contrast, BV produces a thin, grayish-white discharge with a distinct “fishy” odor. These differences in inflammation and discharge help a provider differentiate between the two.
AV also differs from vaginal candidiasis (a yeast infection). The difference is the causative agent: AV is bacterial, while yeast infections are caused by a fungus, typically Candida albicans. While both can cause itching and irritation, a yeast infection’s discharge is thick, white, and has a “cottage cheese” appearance, unlike the discharge in AV.
The Diagnostic Process
Diagnosing aerobic vaginitis involves a few steps to accurately identify the condition and rule out others. A healthcare provider will typically begin with a physical examination to observe the signs of inflammation within the vagina. During this exam, they will look for redness, swelling, and the presence of any erosions or ulcerations on the vaginal walls, which are common indicators of AV. The characteristics of the vaginal discharge, such as its color and consistency, are also assessed.
A sample of vaginal fluid is then collected for further analysis. One of the first tests performed is a pH test. A healthy vaginal pH is acidic, but in cases of AV, the pH is usually elevated. This sample is also examined under a microscope in a procedure known as a wet mount. This microscopic evaluation allows the clinician to observe the vaginal flora directly.
The microscopic view reveals several diagnostic markers. The practitioner will look for a noticeable decrease in or absence of the normal rod-shaped Lactobacillus bacteria. At the same time, they will identify the presence of large numbers of cocci (round bacteria) or bacilli (rod-shaped aerobic bacteria) and inflammatory cells. To formalize the diagnosis, some clinicians use a standardized “AV score,” which grades the severity of the condition based on the abundance of lactobacilli, the level of inflammation, and the types of bacteria present.
Treatment Approaches
The treatment for aerobic vaginitis is aimed at addressing the bacterial overgrowth and the associated inflammation. Since AV is a bacterial infection, the primary course of action involves antibiotics. These may be prescribed as a topical cream or suppository, such as kanamycin or clindamycin, which is applied directly to the vagina. In some instances, oral antibiotics like moxifloxacin may be used instead.
Due to the significant inflammation that characterizes AV, a healthcare provider might also prescribe a topical steroid cream. This is used in conjunction with antibiotics to help reduce the redness, swelling, and irritation more quickly, providing relief from the uncomfortable symptoms. The goal is to calm the inflammatory response while the antibiotics work to rebalance the vaginal flora.
For individuals who are postmenopausal, estrogen therapy may be recommended as part of the treatment plan. Low estrogen levels can contribute to a less resilient vaginal environment, making it more susceptible to infections like AV. Local estrogen therapy can help restore the thickness and health of the vaginal lining.