Can a Yeast Infection Cause a False Positive Genital Herpes Test?

Yeast infections, also known as vulvovaginal candidiasis, is a type of vaginal fungal infection that is caused by a form of fungus known as yeast, or candida.

Yeast infections are not considered a sexually transmitted infection (STI) and can occur in other moist areas on the body like under breast tissue or between skin folds. Yeast infections are very common, and are most frequently seen in women between the ages of 20 to 50 years. Yeast infections are highly treatable but recurrences can be common.

The symptoms of a yeast infection include:

• Vaginal itchiness or irritation
• Vaginal discharge that is white and clumpy like cottage cheese
• Discomfort with sex or urination
  

A yeast infection is diagnosed by examination where your health care provider will inspect the area of concern and obtain a sample of discharge for microscopy or fungal culture. Microscopy identifies yeast under a microscope, and fungal culture will identify yeast if it grows with other cells. 

Genital herpes on the other hand is a viral infection caused by the Herpes Simplex Virus (HSV), HSV-1 or HSV-2 strains. It is chronic and may be recurring. Genital herpes is most commonly caused by HSV-2. The HSV-1 strain is typically oral and responsible for cold sores. However, HSV-1 can also cause genital herpes. Genital herpes is sexually transmitted. The symptoms of a genital herpes infection includes:

• Tingling or itchy sensation in the groin area a few days after sex with an infected individual
• Blister sores around the vagina, cervix, penis, testicles, anus, buttocks or thighs
• Burning sensation with urinating
• Swollen, tender lymph nodes in the groin 
• Fever
• Headaches
• Muscle pain
  

When diagnosing genital herpes, doctors typically swab the sores and test the sample using either a nucleic acid amplification test (NAAT) or a viral culture. The NAAT looks for the virus’s genetic material, while a viral culture tries to grow the virus in the lab. In some cases, your doctor may suggest a blood test called Type-Specific Serology (TSS), which checks for antibodies to HSV-1 or HSV-2. This means it looks for your body’s immune response to the virus, rather than the virus itself.

Symptoms of yeast infections vs. genital herpes

It is possible to be symptom-free with a genital herpes infection, or have mild symptoms that can be confused with a yeast infection or a urinary tract infection.

The important differences in symptoms between a yeast infection and genital herpes are:

• Genital herpes includes painful blisters and sores, while yeast infections will have generalized itchiness and irritation. 
• Genital herpes does not cause discharge, whereas yeast infections often have thick, white discharge.
• Genital herpes can cause flu-like symptoms, but yeast infections do not. 
• Genital herpes is sexually transmitted; yeast infections are not.

Types of genital herpes tests available

Genital herpes can be diagnosed by confirming the presence of the HSV virus in the blister. This is done by opening the blister and taking a sample with a cotton swab or detecting antibodies against the virus in the blood.

As outlined above, the three main methods for testing for genital herpes or HSV are with a NAAT, viral culture, or TSS.

• NAATs are highly accurate, and therefore, the preferred choice for diagnosis. Unfortunately, NAAT tests are not always available. NAATs are commonly used when a viral culture has failed to detect HSV. 
• Viral cultures are best taken as soon as a sore appears. A viral culture is less accurate than the NAAT test, particularly on blisters or sores that have started to heal. Nevertheless, they are easy tests to perform and are widely available. Viral cultures can distinguish if HSV-1 or HSV-2. 
• TSS is a blood test that can identify if someone has HSV-1 or HSV-2, and can estimate how long one has had the infection by measuring the presence of specific antibodies, IgG and IgM. IgG antibodies usually indicate a past infection or exposure, whereas IgM antibodies indicate a recent or active infection. TSS is helpful under particular circumstances, such as:
  • When NAAT or viral culture is negative, but there are symptoms of HSV.
  • To determine if partners have different strains (one has HSV-1, the other HSV-2). 
  • In pregnancy to assess when the infection was acquired to determine risks to the newborn.

TSS testing availability in Canada varies, and it may not be covered by provincial or territorial health insurance plans. 

Can a yeast infection cause a false positive herpes test?

A false positive result indicates that an individual has a disease when they actually do not. A yeast infection will not cause a false positive genital herpes test.

Nevertheless, there are other circumstances in genital herpes testing where a false positive test may occur. 

False positive herpes tests are associated with:

• The blood test type-specific serology (TSS): The TSS is associated with high rates of false positive results. This happens because the test doesn’t directly detect the herpes virus but instead looks for markers in your immune system, making the results harder to interpret. TSS is more likely to give a false positive in people who are at low risk for genital herpes or if it’s done too soon after exposure — outside of the right testing window. For these reasons, it’s not recommended for routine screening or for people without symptoms.
• Cross-Reactivity: HSV-1 and HSV-2 are closely related, and our bodies produce similar antibodies in response to both types. Sometimes, the test might detect HSV-2 antibodies when someone doesn’t actually have HSV-2. Instead, it could be picking up on antibodies from a similar virus. If cross-reactivity is suspected, follow-up tests are usually done to get a clearer and more accurate picture.

Common misconceptions about genital herpes

Genital herpes is a relatively common sexually transmitted infection, with over 10% of Canadian adults infected. However, there are a few misconceptions about it.

These misconceptions include:

• Genital herpes is always symptomatic: Many people with genital herpes don’t even realize they have it. Some may never experience symptoms, while others may have mild symptoms that are easily mistaken for other conditions.
• Genital herpes only affects people with high-risk sexual behaviours: Genital herpes can affect anyone. It only takes one sexual encounter with someone who has the virus to contract HSV, regardless of your sexual history.
• Genital herpes is only spread through sexual intercourse: Genital herpes can also be transmitted through kissing or oral sex, not just intercourse
• Genital herpes will ruin relationships: With open communication and proper management, it’s absolutely possible to have healthy, happy, and intimate relationships while managing genital herpes.

Management and treatment options

Yeast infections are usually treated with antifungal medications like clotrimazole or fluconazole, taken for anywhere from one to seven days. These can come in different forms — either as an oral pill, a vaginal suppository, or a cream you apply directly to the affected area.

For genital herpes, while there’s no cure, flare-ups can be managed with antiviral medications like acyclovir, valacyclovir, or famciclovir. These are usually taken for five to seven days and work best if started within 72 hours of the first symptoms. In some cases, doctors may prescribe extra medication for you to keep on hand, so you can begin treatment quickly when a flare-up starts. While antiviral therapy won’t eliminate the virus, it can help reduce the severity and frequency of outbreaks. Since genital herpes can cause painful sores, pain medication may also be recommended to help with discomfort.

If you’ve been diagnosed with genital herpes, it’s important to inform your sexual partners and avoid sexual activity during an outbreak, when blisters or sores are present. It’s also essential to know that herpes can still be passed on even when there are no visible symptoms. Condoms can help reduce the risk, but they aren’t 100% effective, depending on where the lesions are located or if the virus is being shed without symptoms.

Consulting a healthcare provider

If you have been experiencing sores, pain, discharge, or recurring infections and are uncertain whether you may have a yeast infection or genital herpes, it is important to be assessed by a healthcare provider.

A proper and timely diagnosis is critical for achieving the best treatment outcomes, managing symptoms, preventing complications, and reducing the risk of transmission to others. However, If you’re one of the 6.5 million Canadians without a family doctor, you can consider speaking to a primary care provider on Maple.

It’s quick and simple to register, and we provide access to primary care providers, such as Canadian-licensed doctors and nurse practitioners, within minutes, 24/7/365.

With all conversations taking place over secure text, audio, or video call, we make it easy to take control of your health. 

Understanding the differences between yeast infections and genital herpes is essential for accurate diagnosis and effective treatment. While their symptoms may overlap at times, recognizing the unique characteristics of each condition can help guide proper care. If you’re ever unsure or concerned about your symptoms, it’s important to seek advice from a healthcare provider. They can help clear up any confusion and ensure you receive the right diagnosis and treatment to keep you healthy and comfortable.

The information presented here is for educational purposes and is not meant to replace the advice from your medical professional. Virtual care is not meant for medical emergencies. If you are experiencing an emergency like chest pain or difficulties breathing, for example, please call 911 or go to your nearest emergency room