Vaginal and Vulval Candidiasis

Synonyms: thrush, vulvovaginal candidiasis

This is a yeast infection of the lower female reproductive tract. Rarely, male partners can suffer candidal balanitis.

The infective organism is a fungus that reproduces by budding:

• 90% are due to Candida albicans.
• 5% are due to Candida glabrata.¹

Other fungal infections of the vagina are caused by Saccharomyces cerevisiae (Brewer's yeast) and, rarely, Trichosporon sp.

Candida is a normal commensal organism in the vagina. Pathological infection usually follows a change in the local environment or a decrease in the host's susceptibility to infection.

However, recent research suggests that symptomatic candidiasis is due to an exaggerated immunological response to the presence of candida, rather than a failure of immune mechanisms.²

Incidence and prevalence

• This is difficult to gauge as many women self-treat using over-the-counter (OTC) medication. A Swedish survey of OTC and prescribed anti-fungals for vaginal candidiasis in the mid-1990s, showed about 85-90 cases per 1,000 women in the age group 15-45 years.³
• Post-marketing surveillance of women prescribed quinolone and related antibiotics revealed an incidence of around 600 cases per 100,000 women. The control population (on antidepressants) had about 150 cases per 100,000.⁴
• It is undoubtedly common and estimated to affect about 75% of women in their reproductive years; 10-20% of women have asymptomatic vaginal colonisation with Candida species.
• Peak incidence age 20-40 years.

Risk factors

• Pregnancy⁵
• Diabetes mellitus (impaired glucose tolerance in pregnancy does not seem to be a statistically significant risk factor)⁶
• Treatment with broad spectrum antibiotics (occurs in 28-33%)
• Chemotherapy
• Vaginal foreign body
• Contraceptives may predispose to recurrent vulvovaginal candidosis - but evidence is conflicting and of poor quality¹

Symptoms

• Pruritus vulvae
• White, 'cheesy' discharge
• Dyspareunia
• Dysuria

NB: the presence of foul-smelling or of purulent discharge suggests bacterial vaginitis.

Signs

• Erythema, possibly with fissuring
• Vulval oedema and erythema
• Satellite lesions
• Excoriation

• Genital herpes simplex infection
• Bacterial vaginosis plus infection with coliforms, Shigella sp; Group A streptococci
• Trichomonas vaginalis
• Sexually transmitted diseases (STDs)
• Atrophic vaginitis or hypo-oestrogenism
• Helminthic infection (particularly threadworm/pinworm in young girls)
• Lichen sclerosus et atrophicus
• Contact dermatitis (enquire about new hygiene products)
• Eczema
• Psoriasis
• Mechanical irritation, e.g. long-distance cyclists, sexual abuse in girls
• Recto-vesical fistula
• Underlying immunosuppression/undiagnosed diabetes mellitus
• Urinary tract infection

• Can test vaginal pH, but this is rarely used in practice and there is little evidence to support its use.⁵
  • pH 4.0-4.5 is normal and not altered by presence of candidiasis.
  • pH >5.0 suggests bacterial vaginitis or trichomoniasis.
• Routine culture not required.
• In suspected bacterial/resistant or complicated infection, culture swabs from anterior fornix or lateral vaginal wall.
• Refer to genito-urinary medicine (GUM) clinic if suspected STD.
• MSU if symptoms could be due to urinary tract infection.

NB: cervical smears frequently reveal false positive/asymptomatic candidal colonisation. This does not need further investigation unless there is a reason to suspect an underlying cause, or it is causing problems.

General advice

Routine recommendation of use of vulval moisturisers as soap substitute and regular skin conditioner (advice may need to be given to the patient that this does not constitute "internal use").⁷ Also:

• Loose-fitting, natural fibre underwear
• Avoidance of topical irritants
• Good hygiene

Pharmacological

Since all topical and oral azole therapies give a clinical and mycological cure rate of over 80% in uncomplicated acute vulvovaginal candidiasis, choice is a matter of personal preference, availability and affordability:⁷

• Single episode:
  • Topical azole, e.g. clotrimazole, miconazole. These are less expensive than their oral counterparts, but have some disadvantages.
  • Oral triazole, e.g. fluconazole or itraconazole.
  • Single high-dose oral triazole is effective as treatment for 3-7 days.⁵
  • Topical treatment may worsen burning symptoms in first few days and the patient may prefer oral treatment if inflamed/oedematous vulva.⁸
• Treatment failure:
  • May be due to poor compliance, and a further short course of treatment would then be suitable.
  • Otherwise, use longer course perhaps combining oral and topical treatment. Where azole has failed, may be due to infection by Candida glabrata and nystatin can be more effective.
  • 10% of women have mixed infection with bacteria; may need to send vaginal swab for culture.
  • Consider possibility of underlying disorder.
• Recurrent infections (4 or more episodes per year):
  Send swabs for culture and exclude alternative diagnosis and underlying cause.⁹
  Treatment consists of:
  • Induction period of 1-2 weeks with at least one week of oral agent or 1-2 weeks of topical antifungal, then
  • Maintenance period of 6 months with oral fluconazole 100 mg weekly or topical clotrimazole 500 mg weekly. NB: maintenance therapy with triazoles is unlicensed indication.
  • Treatment can be stopped after 6 months and, if recurrent infection returns, then repeat induction/maintenance.
  • Approximately 90% of women will remain disease-free at 6 months and 40% at 1 year.⁷
  • If infection occurs during maintenance period refer for specialist treatment, as may be due to azole resistance.
  • Non-albicans infection is harder to treat due to increased azole resistance. May use nystatin, boric acid or flucytosine (usually under supervision of secondary care).

NB: there is no evidence to support the treatment of asymptomatic male sexual partners in either episodic or recurrent vulvovaginal candidiasis.

Treatment in pregnancy

Longer courses of topical clotrimazole, miconazole, econazole may be necessary. Nystatin is less effective.¹⁰

Immunocompromised patients

If immunocompromised, especially HIV infection or diabetes, extend treatment period to 7-14 days.⁷

Once diagnosis of uncomplicated candidiasis made, women can be advised to treat further episodes with OTC products. However, advise seeking further medical opinion if⁵:

• <16 or >60 yrs old
• Pregnant or breast-feeding
• Symptoms differing from normal, e.g. malodorous discharge, ulcers, blisters
• Systemic upset
• 2 episodes in 6 months and not seen GP for 1 yr
• Patient/partner has had previous STD
• Abnormal menstrual bleeding/lower abdominal pain
• Previous adverse reaction to anti-fungal treatments, or they are ineffective
• Symptoms persist >7 days.

Alternative treatments

• There is no current evidence to support the use of oral or vaginal lactobacillus for the prevention of vulvovaginal candidiasis.^5,7
• There is insufficient evidence to make any dietary recommendations, including on carbohydrate or yeast intake.
• Zafirlukast 20 mg bd for 6 months may induce remission. Zafirlukast may be considered as maintenance prophylaxis for recurrent vulvovaginal candidiasis, particularly in women with a history of atopy.
• Tea tree oil (and other essential oils) are antifungal in vitro but may cause hypersensitivity reactions. There is currently insufficient evidence to recommend their use.

• Cure rate 80% for uncomplicated cases.⁷
• About 20% will have treatment failure (defined as persisting symptoms at 7- 4 days).⁵
• Recurrent candidiasis (defined as >4 episodes per year) can affect up to 50% of sufferers at a given period in their life.
• Depression and psychosexual problems can occur in women who suffer recurrent episodes.
• Treatment during pregnancy more likely to fail.