A vaginal yeast infection is a fungal infection that causes itching, irritation, and unusual discharge in and around the vagina. It’s one of the most common vaginal infections, with roughly 138 million women worldwide experiencing recurrent episodes each year. Most yeast infections are caused by an overgrowth of a fungus called Candida that naturally lives in the vagina in small amounts.
What Causes the Overgrowth
Your vagina normally hosts a balanced mix of bacteria and yeast. A type of bacteria called Lactobacillus keeps things slightly acidic, with a pH between 4.0 and 4.5. That acidity holds yeast in check. When something disrupts this balance, Candida can multiply quickly and cause symptoms.
Candida albicans is responsible for about 62% of vaginal yeast infections. The rest are caused by related species, most commonly Candida glabrata. This matters because some non-albicans species respond differently to standard treatments.
The most common triggers for overgrowth include:
- Antibiotics. They kill off Lactobacillus along with the bacteria they’re targeting. Without enough Lactobacillus, the vagina becomes less acidic, creating an environment where yeast thrives. This is why yeast infections frequently follow a course of antibiotics.
- Higher estrogen levels. Estrogen increases the amount of glycogen (a sugar) stored in vaginal cells, which feeds yeast. Pregnancy, birth control pills, and hormone therapy all raise estrogen levels, increasing your risk.
- A weakened immune system. Conditions like uncontrolled diabetes or HIV reduce the body’s ability to keep Candida in check.
- Moisture and warmth. Tight clothing, wet swimsuits, and non-breathable underwear create conditions that encourage yeast growth.
What It Feels Like
The hallmark symptom is intense itching in and around the vagina. This can range from mildly annoying to severe enough to disrupt sleep and daily activities. Along with the itch, you may notice redness, swelling, and soreness of the vulva (the outer genital area).
Discharge is another telltale sign. It’s typically white, thick, and clumpy, often compared to cottage cheese. Unlike bacterial vaginosis or other infections, yeast infection discharge usually has no strong odor. If you notice a fishy smell, that points toward a different type of infection. Some people also feel burning during urination or sex, because inflamed tissue is sensitive to contact.
How It Differs From Other Vaginal Infections
Yeast infections are easy to confuse with bacterial vaginosis (BV) or trichomoniasis because all three cause discharge and discomfort. One useful distinction is pH. Yeast infections occur at a normal vaginal pH of 4.0 to 4.5, while BV and trichomoniasis push the pH above 4.5. That’s why some at-home test kits measure vaginal pH as a screening tool, though they can’t confirm a yeast infection on their own.
BV typically produces a thin, grayish discharge with a noticeable fishy odor. Trichomoniasis often causes a frothy, greenish-yellow discharge. Yeast infections produce the thick, white, odorless discharge described above. If you’re unsure which type of infection you have, especially if it’s your first time experiencing symptoms, getting a proper diagnosis matters because the treatments are completely different.
Treatment Options
Most uncomplicated yeast infections clear up within a few days of treatment. Over-the-counter antifungal creams and vaginal suppositories are the first line of defense and are available at any pharmacy without a prescription. These topical treatments typically run for one, three, or seven days depending on the product strength.
For people who prefer a single-dose option, a prescription oral antifungal is a popular alternative. Clinical trials comparing the two approaches show similar cure rates in the short term, around 83 to 85% for both. However, the oral option appears to hold up better over time. In one study, only one patient in the oral treatment group showed signs of recurrence at a follow-up visit, compared to 17 in the topical group. Your choice may come down to convenience and personal preference.
Symptoms like itching and burning often start improving within the first day or two of treatment, but it’s important to finish the full course of a topical product even if you feel better. Stopping early can allow the yeast to bounce back.
Recurrent Yeast Infections
Some people get yeast infections over and over again. The CDC defines recurrent vulvovaginal candidiasis as three or more symptomatic episodes within a single year. This affects fewer than 5% of women, but the impact on quality of life is significant.
Recurrent infections sometimes signal an underlying issue. Uncontrolled blood sugar, a compromised immune system, or a non-albicans Candida species that resists standard treatment can all drive repeat episodes. If you’re dealing with frequent infections, testing to identify the specific yeast species can help guide more effective treatment. Long-term management often involves an extended course of antifungal medication, sometimes taken weekly for several months to suppress regrowth.
What Happens if You Don’t Treat It
A yeast infection won’t resolve on its own in most cases, and symptoms tend to get worse without treatment. The itching intensifies, and the surrounding skin can become increasingly red and inflamed. Repeated scratching can crack or tear the skin, opening the door to a secondary bacterial skin infection.
During pregnancy, an untreated yeast infection won’t affect the developing baby, which is why doctors don’t typically treat infections that aren’t causing symptoms. But symptomatic infections during pregnancy still warrant treatment to prevent worsening discomfort and skin breakdown. In rare cases, a prolonged untreated infection can lead to fatigue, oral thrush, or digestive issues as the fungal imbalance spreads.
Reducing Your Risk
You can’t always prevent a yeast infection, but certain habits lower the odds. Wear breathable cotton underwear and avoid sitting in wet clothing for extended periods. After showering or swimming, dry the genital area thoroughly. Avoid douching or using scented products in or around the vagina, as these disrupt the natural bacterial balance that keeps yeast under control.
If you’re prone to yeast infections after taking antibiotics, let your doctor know. They may recommend starting an antifungal alongside the antibiotic course. For people on hormonal contraceptives who notice a pattern, switching to a lower-estrogen formulation is worth discussing. Managing blood sugar carefully also helps, since elevated glucose feeds Candida growth.