Vulvovaginal candidiasis: Clinical sciences

Vulvovaginal candidiasis, or VVC, is the second most common form of vaginitis, after bacterial vaginosis. It is the result of inflammation of the vagina and vulva due to infection with yeast, most commonly by Candida albicans. Now, asymptomatic colonization of the vagina with Candida species is common. However, when these species overgrow and invade the epithelial cells of the vagina, inflammation occurs.

Your first step in evaluating a patient who presents with a chief concern suggesting vulvovaginal candidiasis is a focused history and physical exam. Patients typically report an abnormal vaginal discharge, as well as vaginal itching. They may also describe vulvar symptoms, such as itching, pain, redness or swelling. Other symptoms might include dysuria; or dyspareunia, which is pain during sex.

When taking history, be sure to ask about any risk factors. First up, there’s the recent use of medications like broad spectrum antibiotics, which can alter the vaginal flora and allow Candida to overgrow. Next, ask if they have recently treated their symptoms with over the counter medications. Many patients successfully treat VVC with over the counter antifungals. However, when patients present with incomplete or partial treatment, it can be more difficult to make a clinical diagnosis. Finally, the medical history should also include questions about underlying medical risk factors for VVC, such as a history of diabetes or immunosuppression, which may include conditions like HIV, or patients on systemic corticosteroids.

Here is a clinical pearl! VVC is uncommon, before puberty, and in postmenopausal patients who are not using hormone replacement therapy, because Candida species are unlikely to proliferate in the vagina in the absence of estrogen.

Now for a focused physical exam. You’ll notice that the vaginal discharge is often thick, white and curd-like. The vulva may appear erythematous with edema and excoriations from scratching, and may develop fissures. Based on these findings, you should suspect VVC.

The next logical step is to confirm your diagnosis.

To do this, obtain samples of the discharge from the vaginal walls and fornices. Assess the discharge first by smearing it on a slide and applying a drop of 10% potassium hydroxide, or KOH, to the preparation. KOH breaks down epithelial cells and white blood cells in the specimen, but does not affect pseudohyphae and spores, which allows for better microscopic visualization of yeast. In addition to microscopy, you should also assess the vaginal pH, and consider sending swabs of the discharge for vaginal culture. You could also consider testing for Candida through polymerase chain reaction, or PCR; or by using a molecular test.

Here is another clinical pearl! The choice of diagnostic testing can vary based on cost and availability. Microscopy is inexpensive, easy to use, and provides rapid results, so it remains the most recommended test, but ​​at times may have large interobserver variability. Second line to microscopy are PCR tests; they're more accurate than microscopy. New DNA-based molecular tests may provide species information with reproducible accuracy; but they are the most expensive and are often unavailable in low resource settings. Lastly, vaginal cultures are rarely performed, since they’re also expensive and take more time, but are useful if microscopy is unavailable or Candida typing and antifungal susceptibility is desired.

Now let’s review our test results. If KOH microscopy is negative for pseudohyphae and spores, and the vaginal pH is greater than 4.5; or if the vaginal culture, PCR, or molecular testing is negative, consider an alternative diagnosis. On the other hand, if KOH microscopy reveals pseudohyphae and spores, as well as many lactobacilli; while the vaginal pH is 3.5 to 4.5; or if vaginal culture, PCR, or molecular testing is positive, you have a diagnosis of vulvovaginal candidiasis.

Once you have made the diagnosis of VVC, let’s see if it’s an uncomplicated or a complicated case.

It is important to assess for complicated disease. This takes in account the number of episodes, symptoms and any comorbidities the patient might have, leading to immunocompromise. This includes patients with diabetes mellitus, HIV infection, or those using medications that suppress the immune system, such as systemic corticosteroids.

First let’s consider uncomplicated VVC.

If the patient had fewer than three episodes of vulvovaginal candidiasis in one year; the symptoms are mild to moderate; and they are not immunocompromised; they are diagnosed with uncomplicated vulvovaginal candidiasis.