Vaginal and vulval candidiasis

Synonyms: thrush, vulvovaginal candidiasis

What is vaginal and vulval candidiasis?

This is a yeast infection of the lower female reproductive tract.

How does vaginal and vulval candidiasis develop (Pathogenesis)?

The infective organism is a fungus that reproduces by budding:

• 85-90% of cases are due to Candida albicans.¹

• Other organisms include Candida glabrata, Candida tropicalis, Candida krusei and Candida parapsilosis.

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

Candida is a normal commensal organism in the vagina. Recent research suggests that symptomatic vaginal and vulval candidiasis (VVC) is not due to opportunistic infection or immunodeficiency but is a hypersensitivity response to the commensal organism. This response may be genetically determined and oestrogen also seems to play a role.

How common is vaginal and vulval candidiasis (Epidemiology)?

Incidence and prevalence²

• Peak incidence age is 20-40 years.

• 70% of women report having had candidal vulvovaginitis at some point in their lifetime.

• 8% have recurrent infection.

• 10% of women have asymptomatic vaginal colonisation with Candida spp. and do not need treatment.

The incidence rate for acute VVC is almost impossible to estimate, as it is under-reported to clinicians because there are effective over-the-counter treatment options. While VVC is not serious, the sheer size of disease burden results in approximately $1.8 billion in medical costs each year and the economic impact due to lost work hours was recently extrapolated to approach an additional $1 billion per annum in the USA alone.³

Risk factors⁴

• Pregnancy.

• Diabetes mellitus (impaired glucose tolerance in pregnancy does not seem to be a statistically significant risk factor).

• Treatment with broad-spectrum antibiotics.

• Chemotherapy.

• Vaginal foreign body.

• Contraceptives may predispose to recurrent vaginal and vulval candidiasis - but evidence is conflicting and of poor quality.

Symptoms and signs of vaginal and vulval candidiasis (presentation)⁵

Symptoms

• Pruritus vulvae.

• Vulval soreness.

• White, 'cheesy' discharge. The discharge is non-offensive. Foul-smelling or purulent discharge suggests bacterial infection.

• Dyspareunia (superficial).

• Dysuria (external).

Symptoms tend to be exacerbated premenstrually and remit during menstruation.

Signs

• Vulval erythema, possibly with fissuring.

• Vulval oedema.

• Satellite lesions.

• Excoriation.

Differential diagnosis²

• Bacterial vaginosis (BV).

• Trichomonas vaginalis.

• Sexually transmitted infections (STIs).

• Atrophic vaginitis or hypo-oestrogenism.

• Helminthic infection (particularly threadworm/pinworm in young girls).

• Lichen sclerosus.

• Contact dermatitis (enquire about new hygiene products).

• Eczema.

• Psoriasis.

• Mechanical irritation - eg, long-distance cyclists, sexual abuse in girls.

• Rectovesical fistula.

• Urinary tract infection.

Diagnosing vaginal and vulval candidiasis (investigations)

• Routine vaginal swabs are not required.

• In suspected bacterial/resistant or complicated infection, take swabs from the anterior fornix or lateral vaginal wall and send for microscopy, culture and sensitivity.

• Self-taken swabs appear to be a valid alternative for detecting candidal infections.⁶

• Take midstream specimen of urine (MSU) if symptoms could be due to urinary tract infection.

Management of vaginal and vulval candidiasis⁴

General advice

• Use a soap substitute to clean the vulval area (advise the patient not to use internally and not to use more than once daily).

• Use an emollient to moisturise the vulval skin.

• Wear loose-fitting underwear (although there is little evidence to support this).

• Avoid applying topical irritants such as perfumed products.

• Good hygiene.

Pharmacological treatment

Both topical and oral azole therapies give a clinical and mycological cure rate of over 80% in uncomplicated acute vaginal and vulval candidiasis.⁴ Personal preference, availability and affordability will affect choice.

For a single episode

• Prescribe either an intravaginal antifungal, such as clotrimazole or miconazole pessaries, or an oral antifungal, such as fluconazole or itraconazole.

• If there are vulval symptoms, consider a topical imidazole as well (eg, clotrimazole or miconazole). Combination packs of pessary/vaginal cream and topical cream are available.

• Note that topical treatment may worsen burning symptoms in the first few days and the patient may prefer oral treatment if they have an inflamed/oedematous vulva.

• Intravaginal clotrimazole, clotrimazole cream and oral fluconazole can be bought over-the-counter.

• Advise the woman to return if her symptoms have not resolved in 7-14 days.

• If symptoms resolve, there is no need for test-of-cure or follow-up.

Severe infections

• Take vaginal swabs and send for culture, microscopy and sensitivity to confirm diagnosis.

• Treat with two doses of oral fluconazole (150 mg) three days apart.

• If oral fluconazole is contra-indicated, treat with a 500 mg pessary of clotrimazole, two doses three days apart.

• Consider adding a topical imidazole cream, such as clotrimazole if vulval symptoms are present.

• Advise the woman to return if her symptoms have not resolved in 7-14 days.

• Seek specialist advice in girls under 16 years of age.

Treatment failure

• Exclude poor compliance. Consider a short course of an oral antifungal if there has been poor compliance with intravaginal treatment.

• If symptoms are improving and compliance has been good, consider prescribing an extended course of either intravaginal or oral treatment.

• Topical treatments can cause vulvovaginal irritation so this should be considered.

• Look for an alternative diagnosis:

  • Consider measuring vaginal pH (Candida spp. pH ≤4.5; bacterial vaginosis and T. vaginalis pH >4.5).

  • Take a vaginal swab for microscopy, culture and sensitivity.

• Seek specialist advice for girls under 16 years old, if:

  • Treatment fails again.

  • The diagnosis is not certain.

  • A non-albicans species is identified.

  • Treatment failure is not explained.

Rarely, male partners may have candidal balanitis. There is no evidence to support the treatment of asymptomatic male sexual partners in either episodic or recurrent vaginal and vulval candidiasis. There is also a lack of evidence for sexual transmission of genital Candida spp. between women who have sex with women.

Treatment in pregnancy⁴

• Intravaginal clotrimazole or miconazole should be used. There is no evidence that one is more effective than another.

• Treatment should be continued for seven days.

• Topical clotrimazole or miconazole may also be used for vulval symptoms.

• Some women prefer to insert pessaries by hand to avoid any damage to the cervix.

• Advise the woman to return if symptoms have not resolved in 7-14 days.

• Refer to a genitourinary medicine clinic if there is any suspicion of an STI.

Immunocompromised patients

For people with controlled diabetes or HIV, manage uncomplicated, severe, and recurrent infections as for women without diabetes or HIV.

Expert opinion is that women with HIV and symptomatic vulvovaginal candidiasis (including recurrent infections) should be treated in an identical way to women who are not HIV positive.⁴ However, vulvovaginal candidiasis does occur more frequently and is more likely to persist in HIV-positive women and longer courses of treatment may be required.

Self-treatment

Once a diagnosis of uncomplicated candidiasis has been made, women can be advised to treat further episodes with over-the-counter products. However, advise seeking further medical opinion if:

• <16 or >60 years old.

• Pregnant or breastfeeding.

• Symptoms differing from normal - eg, malodorous discharge, ulcers, blisters.

• Systemic upset.

• Symptoms not settling after using over-the-counter treatment.

• Two episodes in six months and the patient has not seen a healthcare professional about this for over one year.

• The patient/partner has had a previous STI.

• Abnormal menstrual bleeding or lower abdominal pain.

• Previous adverse reaction to antifungal treatments, or they have been ineffective.

Alternative treatments

• There is no evidence supporting oral or vaginal lactobacillus for the prevention and treatment of vaginal and vulval candidiasis. However, there is no evidence that they cause harm.

• There is only low-quality evidence to support the use of probiotics.⁷⁸

• Tea tree oil and other essential oils have been shown to be antifungal in vitro. However, they may cause hypersensitivity reactions and there is insufficient evidence to recommend their use.

Complications and prognosis

• Cure rate is 80% for uncomplicated cases.²

• Depression and psychosexual problems can occur in women who suffer recurrent episodes.

• Treatment during pregnancy is more likely to fail; hence, the longer treatment period advised.

Prevention of vaginal and vulval candidiasis

Advances in understanding the pathogenic mechanisms that are found in candida have led to vaccine development which is currently in trials.⁹¹⁰

Recurrent vaginal and vulval candidiasis¹¹

Recurrent vaginal and vulval candidiasis is defined as four or more episodes in one year with partial or complete resolution of symptoms in between episodes.¹²

Around 5% of women who develop one episode of vaginal and vulval candidiasis will develop recurrent disease.

It is usually due to infection with C. albicans and various host factors including:

• Diabetes mellitus.

• Immunosuppression.

• Broad-spectrum antibiotic use.

• A possible link with allergy, particularly allergic rhinitis.

Investigation

• Send a high vaginal swab for microscopy, culture and sensitivity to exclude alternative diagnoses.

• Consider measuring vaginal pH (see under 'Treatment failure', above).

• Check FBC and fasting glucose, depending on the level of clinical suspicion.

Treatment⁵

Commence induction treatment

• EITHER three doses of fluconazole 150 mg (1 x 150 mg dose to be taken every 72 hours); OR a topical imidazole treatment for 10-14 days according to response.

• A topical cream may be used in addition to the above for vulval symptoms.

Maintenance and further treatment

• Give a prescription for 'treatment as required', OR prescribe a six-month maintenance regimen.¹²

• In either case, review the patient after six months.

• Possibilities for the maintenance regimen include:

  • 500 mg intravaginal clotrimazole once weekly.

  • 150 mg oral fluconazole once weekly.

  • 50-100 mg oral itraconazole once daily.

  • Zafirlukast 20 mg twice daily for six months may also induce remission. This may be an alternative for maintenance prophylaxis, particularly in atopic women.

  • Cetirizine 10 mg daily for six months has also been shown to induce remission for women in whom fluconazole alone does not provide complete resolution of symptoms.

  • A 2022 Cochrane review found little difference in efficacy between possible regimes.¹³

Prophylaxis reduces relapse to between 9-19% of women, but cure remains difficult to achieve.¹²

Other considerations in recurrent infection

• Give general advice as with non-recurrent infection.

• Consider a contraceptive review:

  • Vaginal and vulval candidiasis does appear to be more common if the vagina is exposed to oestrogen but whether combined hormonal contraceptives actually increase the risk of vaginal and vulval candidiasis is uncertain because the evidence is conflicting.

  • One study shows that switching to a progestogen-only injectable contraceptive may help relieve symptoms in women with recurrent vaginal and vulval candidiasis.¹⁴

  • The effect of switching to other progestogen-only forms of contraception is not certain.

• Optimise glycaemic control in those with diabetes.

• Seek specialist advice in girls under 16 years old.