What Is a Yeast Infection? What to Know About Diagnosis and Treatment

Roughly 75 percent of women will deal with the burning, itching and discomfort associated with a yeast infection at least once in their lifetimes, and almost half will more than once.

But here’s the twist: Most people who think they have a yeast infection actually don’t have one.

“There’s some fairly simple things that can be done that most people don’t bother to do, starting with an accurate diagnosis,” said Dr. Paul Nyirjesy, co-director of the Jefferson Vulvovaginal Health Center in Philadelphia. Here’s what to know.

What is a yeast infection?

The vagina is a delicate ecosystem of microorganisms, including bacteria and yeast, said Dr. Andrew Rubenstein, director of the obstetrics and gynecology department at NYU Langone Health. When that balance is disrupted, it can lay the groundwork for the growth of yeast — typically of a species called Candida albicans, though there are others.

Symptoms include “itching, burning, irritation, swelling, redness, and with these symptoms, women would also have painful intercourse,” said Dr. Jack Sobel, a former dean of the Wayne State University School of Medicine whose research focuses on infections of the female genital tract.

Women might also notice abnormal discharge, but more often than not that’s an indication of a different issue, Dr. Nyirjesy said. “Normal discharge fluctuates a lot,” he explained. “And actually, the infection that causes abnormal discharge much more commonly than yeast infections is bacterial vaginosis, which is an infection that most women have never even heard of.”

What can set off an infection?

A variety of triggers can disrupt the vaginal environment.

Antibiotics are one of the most common, Dr. Nyirjesy said, because they can kill the good bacteria that help keep yeast under control. Diabetes and treatments for diabetes, like a class of drugs called gliflozins, are also associated with an increased susceptibility to yeast infections.

Hormonal fluctuations can stimulate yeast growth, Dr. Sobel said, so some women might be more susceptible to infection if they are on menopausal hormone therapy, and others during certain phases of the menstrual cycle.

Penetrative sex can lead to a yeast infection even though it is not a sexually transmitted disease, Dr. Nyirjesy said. The reasons for that are not fully understood; it was long thought that it might be because of yeast on the penis, but that is uncommon, he said. Another theory is that something about the friction of sex, and the microscopic abrasions it can cause, sets off a colonization of yeast, he noted.

It is unclear why some women recover quickly after one infection and others have recurring infections even when they’ve tried eliminating many of the potential causes, Dr. Nyirjesy said.

Can I diagnose myself?

Self-diagnosis is tricky with yeast infections. Many of the symptoms “are very nonspecific,” Dr. Sobel said. Bacterial vaginosis or an allergic reaction to a new menstrual pad, for example, can cause almost the same symptoms as a yeast infection.

In a 2002 study on which Dr. Sobel was a co-author, women who thought they had a yeast infection and had gone to a drugstore to purchase an over-the-counter treatment were tested to see if they actually had one. Only a third of the 95 participants tested positive for a yeast infection.

There are now several start-ups selling at-home testing kits for yeast. But, Dr. Sobel said, none of them are cleared or monitored by the Food and Drug Administration, so it’s hard to gauge their accuracy.

If you think you have an infection, it is worth seeing a doctor, who will perform a pelvic exam and a test — or a couple of tests, the more accurate of which can take up to a week for results — to confirm the presence of yeast and rule out other causes of discomfort, Dr. Nyirjesy said.

If you have a recurrent infection and have already discussed a treatment plan with your doctor, you probably don’t need to go in for a test every time, Dr. Nyirjesy said.

What treatment options are there?

Antifungals usually bring a yeast infection under control.

The over-the-counter option is Monistat, which is a suppository. The prescription option is a pill called fluconazole, sold as Diflucan. For those fighting off a first-time, nonrecurrent infection, Monistat or a two-pill regimen of Diflucan are about equally effective and should do the trick, Dr. Sobel said. Patients may prefer the pills because they are more convenient and tidier than a suppository. Some studies suggest that fluconazole may increase the risk of miscarriage, so the Centers for Disease Control and Prevention does not recommend its use by pregnant women or those trying to get pregnant.

In 2022, the F.D.A. approved a new antifungal called Vivjoa, which is effective at treating recurrent infections and, according to Dr. Nyirjesy, may be even more effective than Diflucan in those cases. But the approval came with one big caveat: It can’t be given to women of reproductive age. “And who gets recurrent yeast infections? It tends to be women in their reproductive years,” Dr. Nyirjesy said.

Boric acid, which can be found over the counter in suppository form at most drugstores, is also an option. It can be effective particularly for women with recurrent infections, if taken daily for up to two weeks. It is also effective against antifungal-resistant strains of yeast, Dr. Sobel said.

Is there a limit to how much antifungal you can take?

Not really. Women who have recurrent yeast infections can take a maintenance dose of Diflucan for months, even years, Dr. Sobel said. “There are women who take fluconazole prophylaxis for 20, 30 years or more,” he said. “It’s pretty safe. It just needs to be monitored.”

Physicians are increasingly concerned about the development of antifungal-resistant strains of yeast, but they are still rare, Dr. Sobel said. “We do not have new drugs that work against resistant yeast,” he said. Research suggests that roughly 7 percent of patients have infections that are resistant to antifungal drugs.

Can diet tame an infection?

Only in rare circumstances, Dr. Sobel said. Some women with diabetes, for example, might find that eating too many sugary foods can set off an infection. But there is no concrete evidence that for most women, dietary changes can set off, or treat, a yeast infection.

Women are often told to take probiotics or eat yogurt (or even soak a tampon in yogurt and insert it into the vagina), but those suggestions are not backed by science. “That’s all nonsense,” Dr. Sobel said.