A yeast infection is a fungal overgrowth — most often caused by Candida albicans — that disrupts the natural balance of bacteria and yeast in the body. In sexual health, it’s most commonly known as a vaginal yeast infection, but it can also affect the penis, mouth (thrush), or other warm, moist areas.
Yeast infections are not technically sexually transmitted infections (STIs), but they are often triggered or worsened by sexual activity. Friction, hormonal changes, and the introduction of new bacteria during sex can all create conditions that allow yeast to thrive. People can also pass yeast back and forth between partners, especially during unprotected sex.
Yeast infections are extremely common — up to 75% of people with vaginas will experience at least one in their lifetime. They’re usually easy to treat, but they can cause uncomfortable symptoms that mimic STIs and sometimes lead to recurrent issues.
What Are Symptoms of a Yeast Infection?
Yeast infections usually cause intense itching, irritation, and abnormal discharge. The symptoms may be mild at first and worsen over time if left untreated.
In people with female biology, symptoms often include:
- Itching, burning, or swelling in the vulva and vaginal area
- Thick, white vaginal discharge (often described as “cottage cheese-like”)
- Redness, soreness, or cracks in the skin around the vulva
- Pain during sex or urination
In people with male biology (especially uncircumcised men), symptoms can include:
- Itchy rash on the head of the penis
- Redness, burning, or irritation under the foreskin
- White patches or moist buildup
- Discomfort during sex
Not everyone has all these symptoms. Some people may only experience mild itching or irritation — which is why yeast infections are often confused with other STIs or allergic reactions.
What Does a Yeast Infection Look Like?
A yeast infection doesn’t always have a visible appearance, but when symptoms are present, they often include redness, swelling, and a thick white discharge.
On the vulva or vagina, you might see:
- Inflamed skin that looks red, shiny, or cracked
- Swelling of the labia or vaginal opening
- Thick, lumpy discharge that clings to the vaginal walls
On the penis, signs may include:
- Red rash or shiny patches on the glans (head of the penis)
- Small white spots or scaling under the foreskin
- Moist buildup or foul-smelling discharge
While these symptoms can be very uncomfortable, they’re not dangerous and typically resolve with treatment.
How Is a Yeast Infection Transmitted?
Yeast infections are not classified as STIs, but sex can definitely play a role in triggering them. The heat, friction, and exchange of fluids during intercourse can disrupt the vaginal flora and give yeast the upper hand.
You might get a yeast infection from:
- Having sex with a new partner
- Receiving oral sex (yeast can be passed from the mouth)
- Using spermicides, flavored lubes, or scented products
- Using condoms or diaphragms that irritate the vagina
It’s also possible to give a partner a yeast infection, particularly with repeated exposure or unprotected sex. Men can get penile yeast infections, and people of any gender can develop oral thrush from oral-genital contact.
How Do You Test for a Yeast Infection?
Most yeast infections are diagnosed based on symptoms and a pelvic exam. A healthcare provider may:
- Visually inspect the area
- Take a sample of vaginal or penile discharge to examine under a microscope
- Send a sample to the lab to confirm the presence of Candida
If you’ve had frequent yeast infections or your symptoms don’t improve with standard treatment, your provider may do additional testing to identify the specific strain or check for other infections.
How Is a Yeast Infection Treated?
Yeast infections are treated with antifungal medications, which are available both over-the-counter and by prescription.
Treatment options include:
- Vaginal creams or suppositories (e.g., miconazole, clotrimazole)
- Oral antifungal pills (usually fluconazole — a single dose works for many people)
Recurrent infections may require longer courses of treatment or a combination of topical and oral medications. If your partner also has symptoms, they should be treated at the same time to avoid passing the infection back and forth.
Complications of a Yeast Infection
Most yeast infections are mild and go away quickly with treatment. But if left untreated, they can become more painful or spread to other areas.
In people with weakened immune systems (e.g., from HIV, chemotherapy, or uncontrolled diabetes), yeast infections can become more serious and may require stronger treatment. Recurrent yeast infections — four or more per year — can signal a hormonal imbalance or immune issue and may need long-term care.
Outlook & Prognosis
Yeast infections are very treatable. Most people feel better within a few days of starting medication, and full recovery typically takes about a week.
The biggest challenge is recurrence. Some people are prone to frequent yeast infections, especially after sex, during their menstrual cycle, or after antibiotics. Managing underlying triggers and maintaining vaginal health can reduce the risk.
Living With Yeast Infections
Dealing with yeast infections can be frustrating — especially if they keep coming back. Some people feel embarrassed or confused about whether it’s an STI, even though it’s not.
If you’re prone to yeast infections, prevention strategies can help:
- Avoid douching, scented products, or harsh soaps
- Use condoms if you’re sensitive to semen or latex
- Wear breathable cotton underwear and avoid tight clothes
- Change out of wet swimsuits or workout gear quickly
- Urinate and gently wash after sex
Talking openly with your partner about symptoms and triggers can also reduce misunderstandings and help both of you feel more comfortable.
How to Tell Your Partner(s) You Have a Yeast Infection
This isn’t the same as telling someone you have an STI, but it’s still worth sharing if you’ve had recent sexual contact. You might say:
“I’m dealing with a yeast infection — it’s not an STI, but it can be triggered or passed during sex. I’m treating it now and just wanted to keep you in the loop.”
Letting your partner know can help them monitor for symptoms and avoid getting reinfected. It also keeps communication honest and respectful, which builds trust.
Quick Facts About Yeast Infections
- Caused by: Fungi (most often Candida albicans)
- Triggered by: Antibiotics, sex, hormonal shifts, or hygiene products
- Symptoms: Itching, burning, thick discharge, redness, irritation
- Testing: Physical exam; vaginal or penile swab for microscopy or culture
- Treatment: Antifungal creams, suppositories, or oral fluconazole
- Risk if untreated: Pain, chronic recurrence, possible spread in immunocompromised
- How common: Affects 3 in 4 people with vaginas at least once; can also affect men and oral/genital areas
Last reviewed: May 2025
This content is regularly reviewed and updated to reflect the latest medical guidelines.