BV and yeast infections are distinct conditions that affect the vagina, but they are frequently linked. BV does not biologically turn into a fungal infection, as they have different causes. However, the connection between the two is strong and primarily relates to how BV is treated.
Understanding Bacterial Vaginosis and Yeast Infections
Bacterial vaginosis (BV) and yeast infections are two different types of vaginitis, which is inflammation of the vagina. The fundamental difference lies in their biological causes: BV is bacterial, while a yeast infection is fungal.
BV results from an imbalance in the vaginal flora, specifically an overgrowth of anaerobic bacteria, such as Gardnerella vaginalis, replacing beneficial Lactobacilli species. This shift causes the vaginal environment to become less acidic, with the pH often rising above 4.5. A yeast infection (vulvovaginal candidiasis) is caused by an overgrowth of a fungus, most commonly Candida albicans. This fungus multiplies rapidly when the normal protective balance is disrupted.
The Link Between BV Treatment and Fungal Overgrowth
The connection between BV and a subsequent yeast infection stems from the treatment required for bacterial vaginosis. BV is treated with prescription antibiotics, such as metronidazole or clindamycin, designed to eliminate problematic anaerobic bacteria. Unfortunately, these antibiotics are non-selective and kill a broad range of bacteria, including the protective Lactobacilli species.
The loss of these beneficial bacteria is a significant factor because Lactobacilli naturally produce lactic acid, which maintains the vagina’s acidic environment (pH 4.0 to 4.5). When antibiotic treatment depletes the Lactobacilli, the vaginal pH rises, creating a more alkaline environment. This less acidic condition is highly favorable for the growth of the Candida fungus, allowing it to multiply rapidly and cause a secondary yeast infection.
How to Differentiate Symptoms
BV and yeast infections can share general symptoms like itching or discomfort. However, key differences in the discharge and odor help distinguish between the two conditions.
Bacterial vaginosis is typically characterized by a thin, grayish-white or yellow discharge that often has a distinct “fishy” odor. This odor frequently becomes more noticeable after intercourse or during menstruation. In contrast, a yeast infection usually presents with a thick, white discharge often described as having a “cottage cheese-like” consistency. A yeast infection rarely has a strong, unpleasant odor; instead, the primary complaints are intense itching, burning, and redness around the vulva and vaginal opening.
Treatment Options and Managing Recurrence
The standard medical approach for bacterial vaginosis involves a course of prescribed antibiotics, such as oral or topical metronidazole or clindamycin. For a yeast infection, treatment involves antifungal medications, administered as oral tablets (like fluconazole) or as topical creams and suppositories. Self-diagnosing is not recommended, as a medical professional can confirm the specific infection.
Managing recurrence often involves proactive steps to restore the vaginal microbiome. Because BV treatment can trigger a yeast infection, some practitioners may prescribe a single dose of an antifungal like fluconazole concurrently or immediately following the BV treatment. Probiotics containing Lactobacillus species are also a strategy used to help re-establish a healthy vaginal environment after antibiotic use and reduce recurrence risk. For chronic BV, longer-term suppressive therapy with vaginal gels or boric acid suppositories may be used to maintain microbial balance.