Why are yeast infections so complicated?

A vaginal yeast infection, also known as vulvovaginal candidiasis (VVC) or vaginal thrush, is a very common fungal infection caused by an overgrowth of yeast. In fact, approximately 75% of women will experience at least one yeast infection in their lifetime.

Mild to moderate yeast infections that are sporadic or infrequent are normally caused by the yeast, Candida albicans and are called “uncomplicated yeast infections”. This can usually be easily treated using over-the-counter antifungal medication. 

In some cases, the yeast infection cannot be easily treated or it will come back after treatment. This could be because it is a “complicated yeast infection” or because it is not a yeast infection at all! Up to two-thirds of non-prescription drugs used to treat yeast infections are used in error. 

Yeast infections that are severe, recurrent, caused by non-albicans Candida and/or occur in women who are immunocompromised are called “complicated yeast infections”. To maximize treatment success, it is important to know if your symptoms are really down to a yeast infection, and if so, what type of yeast infection it is. To add to all this, sometimes yeast isn’t a problem at all (if you have no symptoms)! 

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We are here to help you navigate through the complicated world of vaginal yeast. Here’s how to decode your yeast infection in 5 simple steps with Juno Bio.

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Step 1: Rule out the more common causes of these symptoms

Typical yeast infection symptoms include itching, white, cottage cheese-like discharge, vulval irritation and pain during sex. However, there are a number of other conditions that could cause these or similar symptoms. 

Vulval irritation

Whilst vulval itching and irritation is a common symptom of yeast infections, most of the time vulval itching is caused by dermatitis, not an infection.

Dermatitis is a term used to describe skin irritation that presents as itchy, red and dry, or a rash. It can be caused by genetics, your immune system, stress, exposure to allergens and irritants, or by a combination of these things.

There are a huge number of irritants or allergens that could potentially upset your delicate vulval skin! Below is a list of just some of the things that could cause irritation. It may be worth ruling these out as the cause of your discomfort before assuming you have a yeast infection.

• Fragranced soap or bubble baths
• Fragranced toilet roll or fragranced sanitary pads
• Cleansing wipes
• Antiseptics, topical medicine or pessaries
• Spermicides, lubricants, condoms or diaphragms
• Washcloths, certain dyes in underwear, tight-fitting clothes
• Bodily fluids

After dermatitis, yeast infections are the most common cause of vulval itching, accounting for 35-40% of cases of vulval itch in reproductive-aged women. Less common causes include other dermatological conditions (e.g. lichen simplex chronicus, lichen sclerosus, psoriasis and lichen planus), other microbial infections (e.g. Staphylococcus aureus, Haemophilus spp., Shigella spp.) or parasitic infections (pinworm, pubic lice and scabies). Itching can also be an early symptom of vulvar cancer, but this is very rare.

Unusual discharge

Vaginal discharge is fluid that keeps the vagina moist and clean. It changes throughout the menstrual cycle, with sexual arousal and during pregnancy. Normal vaginal discharge should be:

• clear or white
• thick and sticky
• slippery and wet
• not strong or unpleasant smelling

If you notice a change in the smell, color or texture of your discharge, it could be a sign of an infection. Most commonly this is due to bacterial vaginosis, yeast infections or trichomoniasis (a sexually transmitted infection; STI). Other STIs, aerobic vaginitis and cytolytic vaginosis can also cause unusual discharge.

Discharge that is white and clumpy but not unpleasant smelling is a sign of a yeast infection. However, cytolytic vaginosis can often be mistaken for a yeast infection as it too causes thick, white discharge.

Pain during sex

Vaginal pain during penetrative sex could be the result of a yeast infection, or it could be caused by an STI, vaginal dryness due to menopause, lack of sexual arousal, vaginismus, or exposure to irritants or allergens (see “Vulvar irritation”).

Pain felt deep inside the pelvis during penetrative sex could be the result of pelvic inflammatory disease (PID), endometriosis or fibroids. There could even be a non-gynecological cause such as irritable bowel syndrome (IBS) or constipation.

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Step 2: Identify the type of yeast

Most yeast infections are caused by the species Candida albicans but in 10-20% of cases of recurrent yeast infections, the cause is another species of Candida, such as Candida glabrata, Candida krusei, ​​Candida tropicalis, Candida utilis, Candida lusitaniae or Candida parapsilosis! These are known as “non-albicans Candida”.

Many non-albicans Candida infections are intrinsically resistant to azoles, a class of anti-fungal medication that is used as a first-line treatment for yeast infections (e.g. Fluconazole). So this could explain why your yeast infection won’t go away.

C. glabrata is not easily recognized using traditional microscopy, so other techniques are recommended to identify non-albicans Candida. The Juno Microbiome Test can identify non-albicans Candida using targeted Next-Generation Sequencing (tNGS).

Example Juno Vaginal Microbiome Test result showing of a non-albicans Candida. 100% abundance means this was the only type of fungus found, therefore it makes up 100% of your vaginal fungi.

Other types of yeast

Although not very well documented, vulvovaginal symptoms could be caused by types of yeast that are not Candida species. For example, Malassezia species are commonly found in the oral and skin microbiomes. When found in the vagina, however, Malassezia could be associated with inflammation and infection-like symptoms.

Other types of microbes

The Juno Vaginal Microbiome test looks for the very rare bacterial and fungal infections that you cannot test for using conventional methods. Regardless of your symptoms, we test everyone for our full range of over 10,000 microbial species so you can rest easy in the knowledge that we’ve looked for it.

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Step 3: Identify the quantity of yeast

Once you have established the type of vaginal yeast that you have, it is useful to understand how much you have. Culture-based tests and many PCR tests cannot tell you this. The microbial load feature of The Juno Vaginal Microbiome Test can tell you how much vaginal yeast you have.

Example Juno Vaginal Microbiome Test results showing Elevated Fungal Load.

In many cases, the presence of yeast in the vagina is perfectly healthy so long as you are not experiencing any vulvovaginal symptoms. Using modern testing techniques, C. albicans has been identified in the vagina of up to 65% of healthy women. Even non-albicans Candida is not harmful in up to 50% of cases. 

However, elevated or high levels of yeast are an indicator of fungal “overgrowth” and are associated with a yeast infection. Your Fungal Load can help you to tell if your level of yeast is cause for concern or not.

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Step 4: Check up on your good bacteria

A healthy vaginal microbiome is typically dominated by protective Lactobacillus bacteria, but women with a yeast infection have been shown to have a significantly reduced proportion of Lactobacillus and higher amounts of potentially disruptive bacteria. This is because of the protective nature of lactobacilli. In vitro (in the lab) studies show that lactobacilli can inhibit the growth and virulence of Candida.

Even within the group of bacteria called Lactobacillus, some species are better than others. Having a vagina that is dominated by the species L. iners means you are more likely to have C. albicans than someone with a vagina dominated by L. crispatus. 

Due to the protective nature of your vaginal bacteria, antibiotic use is associated with yeast infections because antibiotics can disrupt your good bacteria. Vaginal microbiome testing is a great way to check if your bacteria have returned to normal after antibiotic treatment.

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Step 5: Confirm the yeast infection has really gone

When your symptoms subside following treatment you may think the yeast has gone for good, only for your symptoms to come back in full force a few days later! It could be because you never completely got rid of the yeast, or it could be because your vaginal microbiome is lacking good bacteria so is easily disrupted. The only way to know for sure is to test your vaginal microbiome again. 

The Juno Bio team is waiting to help you understand your vaginal microbiome and help you get back to lasting vulvovaginal health. 

‍Get your Juno Vaginal Microbiome test here. To learn more about the symptoms, causes and treatments for yeast infections, check out the yeast infection article in our Vaginal A-Z.