Aetiology, risk factors and management of vulvovaginal candidiasis

Vulvovaginal candidiasis is a type of fungal infection characterized by inflammation of vagina and vulva caused by candida species. It is the second most common cause of vaginitis after bacterial vaginosis. Clinical presentation includes intense vaginal itching, irritation, feeling of burning and soreness and dyspareunia, curdy “cheese”-like discharge, and oedema with normal vaginal pH. Most common causative pathogen is Candida albicans that accounts for 80 to 90% of infection and Candida glabrata is the second highest causative specie. Authors have classified vulvovaginal candidiasis into two major categories: uncomplicated and complicated vulvovaginal candidiasis (VVC). Infections with mild to moderate symptoms and less than four episodes in a year caused by Candida albicans are mainly classified as uncomplicated vulvovaginal candidiasis. While infections caused by other pathogens or with more severe symptoms are classified as complicated vulvovaginal candidiasis. Infections in women where more than 4 episodes occur in a year and have risk factors are classified as complicated recurrent vulvovaginal candidiasis (RVVC). It is estimated that nearly three quarters of all women (70-75%) will develop this infection at least once in their life and half of these women will have another episode (50%), whereas about 5-10% may develop recurrent vulvovaginal candidiasis in their lives (1).

Self-diagnosis or miss-diagnosis makes it difficult to determine prevalence of Vulvovaginal candidiasis. Symptoms of vaginal infections including dysuria, redness, itchiness, vaginal discharge, and pain etc are highly non-specific and often result in over-diagnosis or under-diagnosis by women based on these symptoms (2). Consideration to differential diagnosis is highly important to consider other diagnosis such as bacterial vaginosis, dermatoses, atrophic vaginitis, trichomonas vaginalis. Also, the availability of most antifungal drugs without a prescription and their increase usage makes it difficult to correctly perform epidemiology studies (3).

There are multiple risk factors which account for recurrent vulvovaginal candidiasis in women and are broadly classified as host related factors and behavioural factors.

Occurrence of recurrent vulvovaginal candidiasis in diabetic women is more common than non-diabetic women. High levels of glucose results in the impairment of defensive mechanism and promote adhesion of Candida specie to the vaginal wall. It has been estimated that in diabetic women, the prevalence of vulvovaginal candidiasis is between 32 to 76.5% whereas as only 11 to 23% in women without diabetes (4). Also, women with a history of gestational diabetes mellitus during pregnancy are at higher risk of developing type 2 diabetes particularly in women greater than 35 years of age. A prospective cohort study was conducted in which the risk of developing type 2 diabetes was assessed using the reproductive histories of women. Results showed increased risk of type 2 diabetes mellitus in women with history of gestational diabetes and multiple pregnancies with a hazard ratio of 3.87 (95% CI 2.60-5.75). The American Diabetes Association recommends the screening of women with a history of gestational diabetes at 4-12 weeks postpartum and then at least every 3 years (5).

Some authors have also identified the use of oral contraceptives as one of the risk factors for vulvovaginal candidiasis. Some studies have reported that the incidence of vulvovaginal candidiasis is higher (39-58% versus 20-38%) when women are using oral contraceptive pills as contraception than in women not taking oral contraceptive pills. Also, the prevalence of recurrent vulvovaginal candidiasis is found to be more in women using oral contraceptives pills for longer time. Oral contraceptives are made of higher hormonal dose of synthetic estrogen and progesterone that promote Candida growth by increasing glycogen in vagina and increase the available carbohydrate as nutrients for candida specie. It also stimulate Candida hormone receptors that increases the adhesion of candida to the vaginal walls (1).

The first step in the management of recurrent vulvovaginal candidiasis is to confirm the diagnosis by microbial investigation and identification of the specie. Also, attempts should be made to identify the triggering or precipitating factor such as screening for diabetes or discontinuation of the combined oral contraceptive(6).

After excluding the possibility of other vaginal infections and taking the vaginal swab for cultures and sensitivities, if cultures confirm the presence of Candida albicans then the Therapeutic Guidelines recommends treatment course with fluconazole with a dosage of 150mg on Day 1, 4 and 7 and followed by once-a-week dosing of 150mg fluconazole for a further 6 months. In case of pregnancy or if the patient is planning to conceive, oral fluconazole is not recommended as it is TGA category D drug. Alternative choice in case of pregnancy or planning for pregnancy would be clotrimazole 1% cream administered as 1 applicatorful intravaginally at night for 14 consecutive nights then once a week administration of clotrimazole 500mg pessary inserted vaginally at bedtime for the next 6 months. If cultures indicate the presence of Candida glabrata and azole-resistant species, then therapeutic guidelines recommend the treatment course with nystatin 100000 units/5g vaginal cream to be applied intravaginally with applicator once daily at night-time for 2 weeks (14 nights) in a month for a total of 6 months (3).

Treatment regimen consisting of induction and maintenance regimen has shown to reduce the symptoms and recurrences of recurrent vulvovaginal candidiasis. The intention of maintenance therapy is to supress the symptoms and does not target the elimination of infection therefore chances of recurrence is 50% after the maintenance therapy is stopped which is considered as challenge in the management of recurrent vulvovaginal candidiasis. Also, the emergence of azole-resistant strains due to repeated use of fluconazole imposes another challenge. In case of azole-resistance, other agents that can be used are boric acid vaginal suppositories or capsules, nystatin vaginal suppositories, amphotericin B vaginal suppositories or cream, or flucytosine cream (2).

Also, patient counselling on general management is also important that includes avoiding the use of harsh soaps and perfumes to avoid vulvar irritation. Also, keeping the vaginal area clean and dry and avoiding long exposure to hot tub use. Cool bath may sooth the irritation and provide some relief (7).

The response to the treatment can be monitored by looking at the positive outcomes of the treatments that includes resolution of the symptoms and reduction in the number of reoccurrences. If the desired response is not achieved to the treatment regimen for recurrent vulvovaginal candidiasis, then microbiological cultures can be repeated to assess the development of resistance to the treatment. Also, reassessment of the alternative causes of the symptoms can be done if no adequate clinical response is achieved.