Illustration of viral STI

STD vs. yeast infection: 4 differences in symptoms

Updated Dec 28, 2023. Medically reviewed by Karen Jansen, MS, MD. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.

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Sexually transmitted infections (STIs, also known as STDs, or Sexually Transmitted Diseases) and yeast infections have much in common. With a range of similar symptoms, it’s understandable why many people have difficulties telling them apart.

However, being able to distinguish between the two is critical for protecting your sexual and general health, as both the sexually transmitted infection and yeast infection can advance in severity if undiagnosed and untreated.

Below, find out more about the differences between STD vs. yeast infection in terms of causes, symptoms, and what to do if you think you have either.

What Is An STI?

Sexually transmitted infections are those that are most commonly transmitted through sexual activity. Such infections may be caused by [1]:

  • A virus
  • A bacteria
  • A parasite

Many STIs show no visible symptoms for weeks or months, and some are even asymptomatic. [1] Syphilis, for example, can lie dormant in the body for years without showing symptoms. [2] So, how long can an STD stay dormant without symptoms? Some can be dormant for months or even years.

Other STIs cause only mild symptoms that may go unnoticed. In fact, it’s common to be infected with an STI and not realize it (e.g. HPV), making it more likely you’ll pass it on to a sexual partner.

There are currently over 30 types of known STIs in total. [3] Some of the most common STD or STIs include [3]:

  • Chlamydia
  • Gonorrhea
  • Genital herpes
  • Hepatitis B and C
  • HIV
  • HPV
  • Pubic lice
  • Syphilis
  • Trichomoniasis

Among Americans, the single most common STD is HPV, or human papillomavirus. [4] The CDC estimates as many as 2 in 5 people between the ages of 15 and 59 years have HPV. [4]

How Are STIs Transmitted?

Different types of STIs can be spread in different ways [1]:

  • Some can only be transmitted through oral, vaginal, or anal sex
  • Other types of infections can be spread during intimate contact like kissing or touching
  • Other STIs may be transmitted during childbirth if the parent is infected

Some STIs can also be spread by entering the bloodstream, whether by sharing syringes, body piercing equipment, or tattooing devices. [1] These include [5, 6]:

  • Hepatitis B
  • Hepatitis C
  • HIV

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What Is A Yeast Infection?

Yeast Infection Treatment Online

Unlike the bacteria, viruses, or parasites that cause STIs, yeast is a fungus.

Yeast, a shorthand for vaginal candidiasis, grows naturally in small amounts around different parts of the body, including in the vagina. [7] In most cases, this fungus is entirely harmless. Infections occur when the yeast grows and multiplies out of control. [7]

Yeast thrives in warm, moist places—a trait shared by most of the places where an infection can develop. [7] You can develop a yeast infection [8]:

  • Between skin folds
  • In the mouth (also known as thrush) [9]
  • Around the corners of the mouth (angular cheilitis)
  • Inside the navel
  • Inside the vagina (yeast vaginitis)
  • Around your nail beds
  • On the penis
  • Between the butt cheeks

Most often, yeast infections crop up in the same places as STDs: the mouth, vagina, and the penis. Their location is why they’re easy to confuse with STIs.

Furthermore, yeast infections have several symptoms in common with STIs, including [7]:

  • Vaginal itcing
  • Swelling
  • Irritation, rash, and redness
  • Redness
  • Unusual vaginal discharge
  • Painful urination
  • Burning during urination
  • Pain or discomfort during sex

Yeast Infection Causes

Vaginal yeast infections are very common. Approximately 75% of women and people assigned female at birth will develop at least one in their lives. [7]

The following factors may also make you more susceptible to developing a yeast infection:

  • Recent antibiotic use – Yeast infections occur commonly in people who have taken antibiotics. As the antibiotic kills the offending bacteria, yeast may overgrow. [9]
  • Uncontrolled diabetes – Elevated blood sugar levels are associated with an increased risk of yeast infection. [9]
  • Hormonal changes – If you’re pregnant or taking hormonal contraceptives (e.g. “the pill”), you may be more likely to develop a vaginal yeast infection. [7]
  • A weakened immune system – Your immune system is always working to keep natural flora like yeast in balance. But when the immune system is impaired—whether due to chemotherapy, steroid medications, or a different infection—you’re more vulnerable to developing a yeast infection. [7]
  • Not allowing your body to dry off – Because yeast thrives in warm, moist environments, wearing wet swimsuits or sitting in a hot tub for long periods of time can increase your chances of developing an infection.

That said, if you notice any of these symptoms, it’s a wise idea to reach out to your healthcare provider to ensure it’s properly diagnosed and cared for.

STDs vs. Yeast Infections: How Their Symptoms Differ

If you’re not ready to pay a visit to your healthcare provider, you might consider testing at home for STIs. Additionally, getting to know the key differences between yeast infection and STI symptoms can help you form a clearer picture of what you may have.

With that in mind, let’s look at some symptoms that may help you distinguish between a possible STI and a yeast infection.

Sores or Blisters

Developing sores, warts, or blisters is characteristic of several common STIs, including:

  • Genital herpes – The most apparent sign of herpes is the herpes sore. These crop up during outbreaks and may appear as a cluster of small blisters, over tender, red skin. [10] They might develop near the genitals, rectum, or inner thighs.
  • Syphilis – Syphilis usually begins as a single painless sore (called a chancre) at the site of infection. [11] This is most commonly found around the genitals, though it may also appear on the anus or mouth. [11]
  • HPV – Certain strains of HPV can cause genital warts. [12] Sometimes, warts can also develop in the mouth, throat, anus, and other areas. [13]

Bear in mind that some STIs, like genital herpes, may not present with any symptoms at all. However, yeast infections of the mouth, vagina, or penis will not cause visible sores.

Abnormal Discharge

Both yeast infections and various STIs can trigger abnormal discharge from the genitals, but the color, texture, and odor can differ.

Vaginal yeast infection discharge is usually thin and watery or thick, white, and odorless. [7] The texture of yeast infection discharge is often described as “cottage cheese-like.” [7]

STI discharge tends to differ depending on the cause of infection. For example, gonorrhea can cause the penis to emit a cloudy-white or yellow discharge. [14] It can also cause rectal discharge (this is not a symptom of a yeast infection).

On the other hand, trichomoniasis discharge is more likely to be gray-green or yellow with a foul, fishy odor. [15] Discharge that accompanies a chlamydia infection can also carry a strong, unpleasant odor. [16] If you are experiencing this symptom or any other symptoms while carrying a baby, be sure to consult a healthcare provider to learn more about what happens if you have an STD while pregnant.

Pain

Although yeast infections can be itchy and uncomfortable, they don’t tend to cause pain beyond the affected area. Having intercourse or peeing during a yeast infection can trigger a localized burning sensation, but yeast infections won’t cause pain elsewhere.

Some STIs, however, may lead to pain and discomfort in other areas of the body, such as:

  • Genital herpes – At the first outbreak of a genital herpes infection, some people develop flu-like symptoms like headaches and muscle aches. [10]
  • Chlamydia – When chlamydia spreads, it can cause a dull pain in the lower abdomen or testicles. [16]
  • Syphilis – Secondary-stage syphilis can lead to headaches, muscle pain, or a sore throat. [11] Syphilis that spreads to the eyes (ocular syphilis) can cause eye pain. [17]

Yeast Infection: Cuts on The Skin

You're likely dealing with a yeast infection if you notice small tears or cracks over red skin around your vagina or penis. The skin on these parts of the body is tender and sensitive, and the irritation caused by yeast infections can cause paper-cut-like incisions on the affected areas. Cracks or cuts can also appear at the corners of the mouth with an oral yeast infection. [9]

STIs aren’t known to cause tiny cuts or cracks on the skin’s surface, though the itchiness caused by many STIs may encourage scratching and lead to genital irritation. That said, genital tearing and cracking are uncommon.

Fever

Most yeast infections are considered uncomplicated, expressing only mild to moderate symptoms. In rare cases, invasive yeast infections may lead to a fever—a sign to reach out to a healthcare provider immediately if you’ve already been diagnosed.

However, a fever accompanying other STI symptoms is more likely explained by an STI. Fever may occur in severe cases of [1]:

  • Genital herpes
  • Hepatitis
  • HIV
  • Secondary syphilis

If you experience a sustained fever alongside any other abnormal symptoms, don’t wait—reach out to a healthcare provider to ensure you’re tested, diagnosed, and on track for the proper treatment.

Make STI Testing Convenient with Everlywell

Perhaps the most important takeaway comparing STIs and yeast infections is that it’s nearly impossible to accurately assess your symptoms through observation alone. Many STIs are asymptomatic, and the risks posed by deferring treatment outweigh the ease of getting tested.

With Everlywell, testing for STIs is even easier. Our convenient and discreet at-home STD test for women and STD home test for men check for 6 of the most common infections, so you can feel secure in your status and test as regularly as you need to.

Everlywell also offers convenient STD telehealth options for various conditions. With our online platform, you can receive tailored consultations for yeast infection prescription online, genital herpes online treatment, and comprehensive STD care.

Explore more STI-specific at-home tests from Everlywell by browsing the complete Sexual Health collection today. Don't forget to consider our Everywell+ health tests membership for continuous access to comprehensive sexual health testing options.

Yeast Infection After Sex: Causes, Treatment & Prevention

Trichomoniasis vs. Yeast Infection: What’s the Difference?

Can You Have Sex With A Yeast Infection?

References

  1. Mayo Foundation for Medical Education and Research. (2023, September 8). Sexually transmitted diseases (stds). Mayo Clinic. URL. Accessed December 18, 2023.
  2. Mayo Foundation for Medical Education and Research. (2023b, October 7). Syphilis. Mayo Clinic. URL. Accessed December 18, 2023.
  3. World Health Organization. (n.d.). Sexually transmitted infections (stis). World Health Organization. URL. Accessed December 18, 2023.
  4. Centers for Disease Control and Prevention. (2022, April 18). Std Facts - HPV and men. Centers for Disease Control and Prevention. URL. Accessed December 18, 2023.
  5. Yale Medicine. (2022, September 24). Hepatitis B and C. Yale Medicine. URL. Accessed December 18, 2023.
  6. Hiv.gov. (2022, June 16). How is HIV transmitted?. HIV.gov. URL. Accessed December 18, 2023.
  7. Mayo Foundation for Medical Education and Research. (2023a, January 11). Yeast infection (vaginal). Mayo Clinic. URL. Accessed December 18, 2023.
  8. Cleveland Clinic. (2023, November 27). Unexpected places you can have a yeast infection. URL. Accessed December 18, 2023.
  9. Yeast infection. Johns Hopkins Medicine. (2019, December 2). URL. Accessed December 18, 2023.
  10. Mayo Foundation for Medical Education and Research. (2022, November 22). Genital herpes. Mayo Clinic. URL. Accessed December 18, 2023.
  11. Mayo Foundation for Medical Education and Research. (2023c, October 7). Syphilis. Mayo Clinic. URL. Accessed December 18, 2023.
  12. Mayo Foundation for Medical Education and Research. (2023b, June 30). Genital warts. Mayo Clinic. URL. Accessed December 18, 2023.
  13. Mayo Foundation for Medical Education and Research. (2022a, May 5). Common STD symptoms. Mayo Clinic. URL. Accessed December 18, 2023.
  14. U.S. National Library of Medicine. (n.d.). Gonorrhea | the clap. MedlinePlus. URL. Accessed December 18, 2023.
  15. Mayo Foundation for Medical Education and Research. (n.d.). Trichomoniasis. Mayo Clinic. URL. Accessed December 18, 2023.
  16. C. C. medical. (n.d.). Chlamydia: Causes, symptoms, treatment & prevention. Cleveland Clinic. URL. Accessed December 18, 2023.
  17. Centers for Disease Control and Prevention. (2022a, February 10). STD facts - syphilis. Centers for Disease Control and Prevention. URL. Accessed December 18, 2023.
Karen Jansen, MS, MD is a physician with 28 years of experience including the Emergency Department, hospital ward, and medical office. She was honored to be selected for multiple medical leadership positions including Chief of Pediatrics, Associate Medical Director, and Chief of Staff. Karen also owned, edited, and published a monthly magazine for the healthcare leaders of Northeast Florida. She currently enjoys offering medical writing and editing for medical education, websites, blogs, emails, and social media.
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