Vaginal and Vulval Candidiasis

Synonyms: Thrush, Vulvovaginal candidiasis

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

The infective organism is a fungus that reproduces by budding.

• 90% are due to Candida albicans
• 5% due to Candida glabrata¹
• Remainder are caused by other Candida species, Saccharomyces cerevisiae (Brewer's yeast) and rarely Trichosporon species.

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 anti-depressants) 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 Factors⁵

• Pregnancy
• 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%).⁶
• Chemotherapy
• Vaginal foreign body
• Contraceptives may predispose to recurrent vulvovaginal candidosis - but evidence is conflicting and of poor quality.¹

Symptoms

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

NB: The presence of foul-smelling or purulent discharge suggest bacterial vaginitis.

Signs

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

• Genital herpes simplex infection
• Bacterial vaginosis plus infection with coliforms, shigella, group A streptococci
• Trichomonas vaginalis
• 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 GUM clinic if suspected STD.
• MSU if symptoms could be due to UTI.

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.

Non-drug

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

Drugs

• Single episode:
  • Topical nystatin; 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 as 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.⁷
• 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 C. glabrata and nystatin can be more effective.
  • Ten percent 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.⁸
  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 100mg weekly or topical clotrimazole 500mg 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.
  • 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).

Treatment in Pregnancy

Longer courses of topical clotrimazole, miconazole, econazole may be necessary. Nystatin is less effective.⁹Oral fluconazole and itraconazole should not be used during pregnancy or breast feeding.

Immunocompromised Patients

If immunocompromised, especially HIV infection, or diabetes, extend treatment period to 7 - 14 days.¹⁰

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 breastfeeding
• Symptoms differing from normal e.g. malodorous discharge, ulcers, blisters
• Systemic upset
• 2 episodes in 6/12 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 or they are ineffective
• Symptoms persist >7 days.

Lactobacillus preparations for treatment or prophylaxis are used by some women. There is no current evidence to support their use.⁵

• Cure rate 80% for uncomplicated cases.¹⁰
• About 20% will have treatment failure (defined as persisting symptoms at 7 - 14 days).
• 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.