Yeast Infection or Bacterial Vaginosis: How Do You Tell Which One You Have?

Yeast infection vs bacterial vaginosis (BV): the two can feel alike, but the discharge, odor and itching often differ. Yeast infections often cause itching, burning and thick, white, odorless discharge. BV more often causes thin, gray or white discharge with a fishy odor and less itching. Symptoms overlap, so a clinician usually needs an exam and testing to be sure. This article compares the two, explains why self-treating can backfire, and lists when to get care urgently.

Yeast infection or bacterial vaginosis: the main differences

Both conditions fall under vaginitis, the general term for inflammation or infection of the vagina. MedlinePlus (NIH) describes vaginitis as having several causes, including yeast, bacteria and other infections, so similar symptoms can come from different problems. You can read its overview at MedlinePlus: Vaginitis.

The table below shows the patterns clinicians often look for. Individual experiences vary, and many people do not fit neatly into one column.

What causes a yeast infection

Candida is a fungus that normally lives in small amounts on the skin and in the vagina. A yeast infection can develop when it overgrows. Antibiotic use, pregnancy, uncontrolled diabetes, a weakened immune system and hormonal changes are associated with a higher chance of this happening. Several factors usually contribute, and sometimes no clear trigger is found. More detail is on MedlinePlus: Yeast Infections.

What a yeast infection tends to feel like

Typical symptoms include itching or irritation of the vagina and vulva, burning, redness or swelling, pain with sex, and a thick white discharge. The skin around the vulva can look red or have small cracks. Discharge may be minimal in some people, with itching as the main complaint.

What causes bacterial vaginosis

BV involves a change in the mix of bacteria that normally live in the vagina. Protective bacteria decrease and other bacteria increase. The exact mechanism is not fully understood. The CDC Sexually Transmitted Infections Treatment Guidelines cover BV, and it is associated with sexual activity, new or multiple sexual partners and douching, but it also occurs in people who are not sexually active. Many people with BV have no symptoms at all.

What BV tends to feel like

When symptoms occur, the most noticed ones are a fishy odor and thin discharge. Itching and burning can be present but are often milder than with a yeast infection. Odor that seems stronger after sex or around a period is commonly reported.

Why guessing can backfire

Many people assume any vaginal itch is yeast and reach for an over-the-counter antifungal. If the cause is actually BV, an antifungal is not expected to help, and treatment gets delayed. Other conditions can look similar too, including trichomoniasis, genital herpes, irritation from soaps or products, and skin conditions of the vulva. See MedlinePlus: Genital Herpes and MedlinePlus: Vulvar Disorders for examples.

Clinicians combine your history, a pelvic examination and lab testing, which may include checking the pH of vaginal fluid and looking at a sample under a microscope or running a lab test. The CDC guidelines describe diagnosing BV and candidiasis with an exam plus testing such as vaginal pH and microscopy, because symptoms alone can be unreliable.

How each one is treated

Yeast infections are usually treated with antifungal medicine, either as a cream, suppository or oral tablet. Some creams and suppositories are available without a prescription. The oral tablet (fluconazole) needs a prescription. If you are pregnant or might be, do not take oral fluconazole. Talk to your prenatal clinician first. Treatment in pregnancy is usually a vaginal cream or suppository used for about 7 days, chosen with a clinician. Tell your prescriber or pharmacist about all medicines you take, including blood thinners such as warfarin, statins and medicines that affect heart rhythm (QT-prolonging drugs), since fluconazole can interact with them, and tell them about any liver problems.

Some studies link oral fluconazole in pregnancy with a higher risk of miscarriage, which is part of the reason for the caution; the evidence is observational, so ask your prenatal clinician about the details. The CDC treatment guidelines for vulvovaginal candidiasis recommend topical azole antifungals instead during pregnancy, often as a longer course. If you are or might be pregnant, talk with your prenatal clinician before using any antifungal, including over-the-counter creams and suppositories. If this is your first episode or you are unsure of the cause, it is reasonable to have it diagnosed before self-treating with over-the-counter products.

According to the CDC Sexually Transmitted Infections Treatment Guidelines, BV is treated with prescription antibiotics, taken by mouth or used as a vaginal gel or cream. Antibiotics only work on bacteria, as explained on MedlinePlus: Antibiotics.

Read the label of any product and follow your clinician's or pharmacist's directions. Metronidazole and tinidazole, which are used for BV, are labeled with warnings about alcohol, and the labels advise avoiding it during treatment and for several days afterward, so ask your prescriber or pharmacist how long applies to your medicine. Both labels also carry a boxed warning about tumors seen in animal studies and advise using these medicines only when needed. Ask your prescriber about this, and do not stop a prescribed course on your own. Do not change the dose or length of a prescribed course without asking. Tell your clinician if you could be pregnant, are breastfeeding or take other medicines, since pregnancy, especially the first trimester, can affect which medicine is chosen.

When over-the-counter treatment may be reasonable

Some people who have had a yeast infection diagnosed by a clinician before, and who recognize the same symptoms, use an over-the-counter antifungal. Many clinicians suggest seeing someone first if this is your first episode, if you are unsure, if you are pregnant, or if symptoms do not improve after treatment. Ask your pharmacist whether a product suits you.

Pregnancy and vaginal symptoms

Vaginal infections during pregnancy deserve a clinician's attention rather than self-treatment. BV in pregnancy has been associated with preterm birth in some studies. The CDC STI Treatment Guidelines (bacterial vaginosis section) advise evaluating and treating pregnant people who have symptoms, so ask your prenatal clinician about testing. MedlinePlus covers general risks on its Infections and Pregnancy page. Urinary symptoms are a separate issue, discussed in our article on UTI during pregnancy.

Things that may reduce irritation and recurrence

• Avoid douching. It can disturb the normal balance of vaginal bacteria.
• Skip scented soaps, sprays, wipes and bubble baths around the vulva, and wash with plain water or a mild, unscented cleanser.
• Wear breathable cotton underwear and change out of wet swimsuits or sweaty clothes promptly.
• Wipe front to back.
• If you have diabetes, talk with your clinician about glucose management, since higher glucose levels are associated with yeast infections.

These steps are general comfort measures and may reduce the chance of irritation, but they do not guarantee prevention.

If symptoms keep coming back

Repeated episodes of either condition are worth discussing with a clinician. They may check for another diagnosis and look at risk factors such as diabetes or recent antibiotics. Recurrent yeast infections are generally defined as three or more symptomatic episodes in a year; a clinician can confirm the diagnosis and discuss the longer or suppressive regimens described in the CDC treatment guidelines, which also cover recurrent BV. Recurrent symptoms can also reflect conditions such as vulvar skin disorders or sexually transmitted infections. If you have new partners or are at risk for infection, testing for other infections may be appropriate. Our article on pelvic pain with unusual discharge covers pelvic inflammatory disease.

Partners and sex during treatment

For BV, CDC guidance has not found routine treatment of male sex partners to be beneficial, while female sex partners may need evaluation, since BV can occur in both partners. Yeast infections are not usually treated as sexually transmitted, though a partner with symptoms may want to be seen. Ask your clinician whether to wait on sex until treatment is complete and whether anyone else needs evaluation.

Menopause and similar symptoms

After menopause, dryness and thinning of vaginal tissue can cause burning, irritation and discomfort that resemble infection. Our article on vaginal dryness and painful sex after menopause covers that topic. A clinician can help sort out whether infection or tissue changes are involved.

A rare emergency: toxic shock syndrome

Toxic shock syndrome is much less common than yeast infections or BV, and vaginal symptoms alone do not suggest it. It is a serious bacterial illness that has been associated with tampon or menstrual cup use. Warning signs can include a sudden high fever, a rash that looks like sunburn, vomiting or diarrhea, dizziness or fainting, and confusion. It can become serious, so do not wait to see whether symptoms settle. If these symptoms appear, remove the tampon or cup and get emergency care now, and call 911 if you feel faint, confused or very weak.

Fever with shaking chills, severe weakness or a racing heartbeat together with genital symptoms can also point to a serious pelvic or bloodstream infection, such as sepsis or a pelvic abscess. That combination needs emergency care rather than a routine appointment, and fainting, confusion or trouble breathing with fever means calling 911.

What to tell your clinician

• When symptoms began and how they have changed.
• The color, amount and smell of any discharge.
• Any products, treatments or douches you have used.
• Recent antibiotics, new partners, pregnancy or possible pregnancy.
• Whether you have diabetes, liver disease or a condition that affects immunity.

If you can, avoid using vaginal creams or inserts shortly before an appointment, since they can make testing harder to interpret. Ask the office if you are unsure.

When to Seek Medical Care