Yeast Infection of the Vagina

Overview

A vaginal yeast infection is a fungal infection that causes itching, irritation, and discharge in the vagina and the surrounding skin of the vulva. It happens when a yeast called Candida, which normally lives in small amounts in the vagina, grows out of balance and multiplies. Most yeast infections are caused by a species called Candida albicans.

The vagina naturally contains a mix of yeast and helpful bacteria that keep each other in balance. When something disturbs this balance, such as a course of antibiotics or a change in hormones, the yeast can overgrow and cause symptoms. Understanding this balance explains why yeast infections often follow specific triggers rather than appearing at random.

Yeast infections are very common, and most people with a vagina will have at least one during their lifetime. They are uncomfortable but usually not serious, and they respond well to antifungal treatment. A yeast infection is not classed as a sexually transmitted infection, although sexual activity can sometimes trigger symptoms.

Symptoms

Symptoms can range from mild to intense and often include:

• Itching and irritation in the vagina and vulva
• A thick, white, odorless discharge that may look like cottage cheese
• Burning, especially during urination or sex
• Redness, swelling, or soreness of the vulva
• Small cracks or tenderness of the surrounding skin

Unlike some other vaginal infections, a yeast infection usually does not cause a strong or fishy odor. Symptoms that do not improve with treatment, or that come with a foul smell or fever, may point to a different problem and should be checked.

Causes

Yeast infections develop when the normal balance of yeast and bacteria in the vagina is upset, allowing Candida to overgrow. Common triggers include:

• Antibiotics: They can reduce the helpful bacteria that normally keep yeast in check.
• Hormonal changes: Pregnancy, hormonal birth control, and the menstrual cycle can shift the vaginal environment.
• High blood sugar: Poorly controlled diabetes encourages yeast growth.
• A weakened immune system: From illness or certain medications.
• Warmth and moisture: Tight, non-breathable clothing can create conditions yeast favors.

Risk Factors

• Recent or repeated antibiotic use
• Pregnancy
• Diabetes, especially when blood sugar is high
• A weakened immune system
• Use of estrogen-containing birth control or hormone therapy
• Frequent douching or use of scented vaginal products

Diagnosis

A clinician can usually diagnose a yeast infection from the symptoms and a pelvic examination. To confirm the cause and rule out other infections, they may:

• Examine a sample of discharge: Looking at it under a microscope to identify yeast.
• Test the vaginal pH: Yeast infections usually do not raise the pH the way bacterial infections do.
• Send a culture: Helpful for infections that keep returning or do not respond to treatment.

Because bacterial vaginosis and trichomoniasis can cause similar discomfort, testing helps make sure the right treatment is used.

Treatment

Most yeast infections clear up with antifungal medicine.

• Topical antifungals: Creams, ointments, or suppositories placed in the vagina, used for one to seven days.
• Oral antifungal: A single tablet taken by mouth is an option for many people.
• Longer courses: Repeated or severe infections may need a longer or maintenance regimen guided by a clinician.

Over-the-counter antifungal products work for many uncomplicated infections. If you are pregnant, have frequent infections, or are unsure of the diagnosis, see a clinician before self-treating. It also helps to finish the full course of treatment even if symptoms ease early, and to avoid scratching, which can irritate the skin further. Most people feel better within a few days of starting treatment, and complete relief usually follows within about a week.

Prevention

• Wear breathable cotton underwear and avoid staying in damp clothing
• Avoid douching and scented vaginal sprays, washes, or wipes
• Keep blood sugar well controlled if you have diabetes
• Take antibiotics only when needed
• Change out of wet swimwear or workout clothes promptly

When to See a Doctor

See a clinician if this is your first suspected yeast infection, if symptoms do not improve after treatment, or if they keep coming back (four or more times a year). Also seek care if you have:

• A foul-smelling or unusual discharge
• Fever, pelvic pain, or feeling generally unwell
• Sores or significant swelling
• Symptoms during pregnancy

Related Topics

Frequently Asked Questions

References

1. Centers for Disease Control and Prevention (CDC). Vaginal Candidiasis.
2. Mayo Clinic. Yeast infection (vaginal) — Symptoms and causes.
3. Office on Women's Health, U.S. Department of Health and Human Services. Vaginal yeast infections.
4. MedlinePlus, U.S. National Library of Medicine. Vaginal yeast infection.