Vaginal thrush is a common yeast infection caused by an overgrowth of Candida, a fungus that naturally lives in and on your body. Most cases are caused by Candida albicans, though other Candida species can occasionally be responsible. Around three out of four women will experience at least one episode in their lifetime, and for many, it comes back more than once.
The infection develops when something disrupts the balance of microorganisms in the vagina, allowing Candida to multiply beyond its usual levels. Importantly, thrush is not a sexually transmitted infection, and it occurs at a normal vaginal pH (around 4.0 to 4.5), meaning the vaginal environment can be acidic and healthy-seeming while still hosting an overgrowth.
What Causes the Overgrowth
Candida is always present in small amounts in the vagina. It only becomes a problem when conditions shift in its favor. The most common triggers fall into a few categories: medications, hormonal changes, and immune system factors.
Antibiotics are one of the most frequent culprits. They kill off the protective bacteria (especially lactobacilli) that normally keep Candida in check. Without that competition, the yeast multiplies quickly. Steroids and chemotherapy can have a similar effect by suppressing your immune response.
Hormonal shifts also play a significant role. Pregnancy raises estrogen levels, which increases glycogen in vaginal tissue and gives Candida more fuel to grow. Hormonal contraceptives, particularly birth control pills, carry a similar risk. This is why thrush is more common during reproductive years and less common before puberty and after menopause.
Uncontrolled diabetes creates a high-sugar environment throughout the body, including vaginal secretions, which encourages yeast growth. A weakened immune system from conditions like HIV also makes it harder for the body to keep Candida populations in balance.
How It Feels
The hallmark symptom is itching, sometimes intense, around the vulva and vaginal opening. Many women also experience a burning sensation, particularly during urination or sex. The skin around the vulva may look red, swollen, or feel sore to the touch.
Discharge is another key sign. Thrush typically produces a thick, white discharge with a cottage cheese-like texture. It’s usually odorless or has only a mild yeasty smell. The amount of discharge varies, and some women have very little.
Thrush vs. Bacterial Vaginosis
Thrush is often confused with bacterial vaginosis (BV) because both cause abnormal discharge, but the two infections look and feel quite different. BV produces a thin, grayish or yellowish discharge with a strong, fishy odor. Thrush produces thick, white, clumpy discharge that typically has no noticeable smell. The other major distinction is itching: thrush almost always causes it, while BV generally does not.
The vaginal pH also differs between the two. Thrush occurs at a normal pH of around 4.0, while BV raises the pH above 4.5. This is one reason a healthcare provider may test your vaginal pH as part of a diagnosis. The treatments are completely different, so getting the right diagnosis matters. Antifungals treat thrush, while BV requires antibiotics.
How It’s Treated
Most uncomplicated cases of vaginal thrush clear up within a few days of starting treatment. You have two main options: a topical antifungal cream or pessary (inserted into the vagina), or an oral capsule.
The oral route is a single 150mg dose of fluconazole, which is often the most convenient option. Topical treatments, such as clotrimazole creams and pessaries, are applied directly to the affected area over one to seven days depending on the strength. Both approaches are similarly effective for straightforward cases, and many are available over the counter without a prescription.
Symptoms like itching and soreness usually start improving within a day or two, though it can take up to a week for the infection to fully resolve. If your symptoms haven’t improved after a full course of treatment, it’s worth getting tested to confirm the diagnosis, since BV and other conditions can mimic thrush.
When Thrush Keeps Coming Back
Some women deal with thrush four or more times a year, which is classified as recurrent vulvovaginal candidiasis. This pattern can be linked to frequent antibiotic use, uncontrolled diabetes, or other underlying health factors, but in many cases there’s no clear cause.
The treatment approach for recurrent thrush is more intensive. A typical regimen involves taking 150mg of fluconazole once every 72 hours for three doses to knock out the active infection, followed by a 150mg dose once a week for up to six months. This maintenance phase helps suppress the yeast and break the cycle of reinfection. If you’re experiencing frequent episodes, it’s worth having a healthcare provider investigate possible underlying causes like blood sugar issues or immune system changes.
Do Probiotics Help?
There’s growing interest in using probiotics alongside standard antifungal treatment. The theory is that oral lactobacilli can travel from the gut to the vaginal area and help restore the protective bacterial balance that keeps Candida in check.
A randomized trial from India compared standard fluconazole treatment alone to fluconazole combined with oral probiotic capsules containing Lactobacillus strains. The group taking probiotics alongside their antifungal achieved a 97% complete remission rate, compared to 90% in the antifungal-only group. No side effects were noted in either group. While promising, the difference wasn’t statistically significant in this study, meaning probiotics appear safe to try but aren’t a proven substitute for antifungal treatment.
Reducing Your Risk
You can’t always prevent thrush, especially when antibiotics or hormonal changes are involved. But a few practical habits can lower the odds:
- Wear cotton underwear and avoid tight-fitting clothing, both of which help keep the area dry and ventilated. Candida thrives in warm, moist environments.
- Keep the vulval area clean and dry. Wash with plain water or a gentle, unscented wash. Scented soaps, bubble baths, and douches can disrupt the vaginal environment.
- Change out of wet clothing promptly, especially swimwear and workout clothes.
- Be aware of antibiotic-related risk. If you’re prone to thrush and need a course of antibiotics, you may want to have an antifungal treatment on hand to use at the first sign of symptoms.
If you’re managing diabetes, keeping blood sugar well controlled is one of the most effective things you can do to reduce your risk of thrush and other Candida infections.