Vaginal candidiasis

Vaginal candidiasis or vulvovaginal candidiasis, more commonly known as thrush, is an unpleasant condition that affects women. Vaginal candidiasis is a symptomatic inflammation of the vagina and/or vulva caused by a superficial fungal infection (usually yeasts of the genus Candida), and most commonly occurs in women of reproductive age (National Institute for Health and Care Excellence (NICE), 2023a).

The condition is generally classified as:

• Acute vaginal candidiasis: a first or single isolated presentation
• Recurrent vaginal candidiasis: at least four episodes during a 12-month period, with at least two episodes confirmed by microscopy or culture, when the patient is symptomatic (Saxon et al, 2019)

Symptoms of vaginal candidiasis are very common, with estimates suggesting that approximately 75% of women will have at least one episode in their lifetime, and 40–45% of women will have two or more episodes (Centers for Disease Control and Prevention, 2022). True prevalence rates are difficult to confirm, because many women may self-treat the condition with over-the-counter medications. Presentation frequently differs and varies in severity (from mild to severe). The most common symptoms of vaginal candidiasis include:

• vaginal soreness and itching
• vaginal discharge – this is usually thick and white in colour and has an appearance which resembles cottage cheese and is typically not odorous
• the vaginal area is very red (erythematous) on examination
• the skin around the vaginal and vulval areas can be cracked and inflamed
• intercourse may be uncomfortable or painful
• in some cases, the infection can be more severe and the area of redness may extend to

In healthy adult women, during the reproductive years, the vaginal flora is a host to many microorganisms, including Candida, which do not usually cause any problems unless there are changes to the environment. Overgrowth of the causative organism leads to vaginal infection.

Lactobacillus is the most frequently isolated organism from the vagina of healthy women, and its role is to maintain an acidic pH, with the production of substances which keep the vagina healthy and prevent the development of infection by Candida or any other pathogenic organisms (Chen et al, 2021). Lactobacillus spp. normally flourishes in the vaginal anaerobic environment and produces various antimicrobial compounds, such as lactic acid, hydrogen peroxide (H2O2) and bacteriocins. These contribute to a healthy vaginal microbiome and establish a defence against invading pathogens (Chen et al, 2021).

Minimal disturbance to the healthy environment is needed for Candida organisms to become pathogenic and cause the

Diagnosis can often be made on history and clinical examination. Investigations are not routinely needed for women presenting with typical symptoms, but a high vaginal swab can be undertaken if the diagnosis is uncertain or the patient’s symptoms are resistant to treatment or recurrent (NICE, 2023a). When clinical examination is not possible, a self-collected vaginal swab for microscopy and culture is an acceptable alternative to samples taken by clinicians (Barnes et al, 2017).

Treatment usually involves both oral and topical medications, with a clinical and mycological cure rate of over 80% (Saxon et al, 2019). Please refer to the most up-to-date guidance for specific prescription and dosage recommendations.