Vulvovaginal candidiasis is the name often given to Candida albicans infection of the vagina associated with a dermatitis of the vulva (an itchy rash). ‘Vaginal thrush’, ‘monilia’, and vulvovaginal candidosis are also names used for Candida albicans infection.
What causes vaginal discharge?
Most women notice from time to time that they have a discharge from the vagina. This is a normal process which keeps the mucous lining of the vagina moist. The discharge is usually clear but may dry on underclothes leaving a faint yellowish mark. This type of discharge does not require any medication even when quite profuse, as is often the case in pregnancy.
Vaginal discharge may also be due to microorganisms:
- Vulvovaginal candidiasis (discussed here).
- Trichomoniasis (due to a small parasite,Trichomonas vaginalis). This causes a fishy or offensive odour and yellow, green or frothy discharge.
- Bacterial vaginosis (due to an imbalance of the amounts of bacteria which live in the vagina). This causes a thin, white/grey discharge and offensive odour.
Excessive vaginal discharge may also be due to injury, foreign bodies and other causes of vaginitis.
What is the cause of vulvovaginal candidiasis?
About 20% of non-pregnant women aged 15 to 55 harbour Candida albicans in the vagina. Most have no symptoms and it is harmless to them. Overgrowth of Candida albicans causes a heavy white curd-like vaginal discharge, a burning sensation in the vagina and vulva and/or an itchy rash on the vulva and surrounding skin.
Oestrogen causes the lining of the vagina to mature and to contain glycogen, a substrate on which Candida albicans thrives. Lack of oestrogen in younger and older women makes vulvovaginal candidiasis much less common.
Overgrowth of Candida albicans occurs most commonly with:
- Higher dose combined oral contraceptive pill and oestrogen-based hormone replacement therapy
- A course of broad spectrum antibiotics such as tetracycline or amoxiclav
- Diabetes mellitus
- Iron deficiency anaemia
- Immunological deficiency e.g., HIV infection
- On top of another skin condition, often psoriasis, lichen planus or lichen sclerosus.
- Other illness
What are the symptoms?
Symptoms of vulvovaginal candidiasis, i.e., an overgrowth of Candida albicans, include:
- Itching, soreness and/or burning discomfort in the vagina and vulva
- Heavy white curd-like vaginal discharge
- Bright red rash affecting inner and outer parts of the vulva, sometimes spreading widely in the groin to include pubic areas, inguinal areas and thighs.
These may last just a few hours or persist for days, weeks, or rarely, months. Vulvovaginal candidiasis may recur just before each menstrual cycle (cyclic vulvovaginitis).
Symptoms may sometimes be aggravated by sexual intercourse.
How is the diagnosis of vulvovaginal candidiasis made?
The doctor diagnoses the condition by inspecting the affected area and recognising typical clinical appearance. The pH of the discharge tends to be less than 4.5 and the diagnosis is often confirmed by a vaginal swab or vaginal smear. In recurrent cases the swab should be repeated after treatment to see whether Candida albicans is still present.
It is best to avoid treatment for four weeks prior to a swab to improve the chance of positive culture. Repeated self-sampling may be used if symptoms are not present at the time of medical examination. The doctor should provide swabs, completed laboratory forms, lab bags and instructions where to send or deliver the specimens.
Swab results can be misleading because the Candida albicans can be present without causing symptoms, and it can only be cultured if a certain amount is present. Swabs from outside the vagina can be negative, even when the yeast is present inside the vagina and there is a typical rash on the vulva. This is because the vaginal discharge has caused an irritant dermatitis, rather than the rash being directly due to infection.
In other cases, a different species of yeast i.e. a non-albicans candida is found. This is not likely to cause significant symptoms; researchers debate whether these yeasts cause disease or not. Antifungal agents may not clear non-albicans candida from the vagina but it tends to disappear in time by itself.
Treatment of vulvovaginal candidiasis
Appropriate treatment for Candida albicans infection can be obtained without prescription from a chemist. If the treatment is ineffective or symptoms recur, see your doctor for examination and advice.
There are a variety of effective treatments for candidiasis. Topical antifungal pessaries or vaginal tablets containing clotrimazole or miconazole are usually recommended – in mild cases a single treatment is all that is necessary. A cream formulation may be preferred. Oral antifungal medicines containing fluconazole or itraconazole may be used if Candida albicans infection is severe or recurrent.
The creams can be used safely in pregnancy, but the tablets are best avoided.
Not all genital complaints are due to candida, so if treatment is unsuccessful it may because of another reason for the symptoms.
Occasionally Candida albicans infection persists despite adequate conventional therapy. In some women this may be a sign of iron deficiency, diabetes mellitus or an immune problem, and appropriate tests should be done.
It is now thought that women who experience recurrent vulvovaginal Candida albicans do so because of persistent infection, rather than re-infection. The aim of treatment in this situation is therefore to avoid the overgrowth of candida that leads to symptoms, rather than necessarily being able to achieve complete eradication or cure.
There is some evidence that the following measures can be helpful:
- Cotton or moisture-wicking underwear and loose fitting clothing – avoid occlusive nylon pantyhose.
- Soaking in a salt bath. Avoid soap – use a non-soap cleanser or aqueous cream for washing.
- Apply hydrocortisone cream intermittently, to reduce itching and treat secondary dermatitis affecting the vulva.
- Treat with an antifungal cream before each menstrual period and before antibiotic therapy to prevent relapse.
- A prolonged course of a topical antifungal agent is occasionally warranted (but these may themselves cause dermatitis or result in proliferation of non-albicans candida).
- Oral antifungal medication (itraconazole or fluconazole) may be taken regularly and intermittently (e.g. once a month). The dose and frequency is quite variable, depending on the severity of symptoms. Oral antifungal agents may be unsuitable in pregnancy. They may require a prescription. In New Zealand, single dose fluclonazole is available over the counter at pharmacies.
- Boric acid (boron) 600mg as a suppository at night may help to acidify the vagina and reduce the presence of yeasts (albicans and non-albicans candida).
The following measures have not been shown to help.
- Treatment of sexual partner – males may get a brief skin reaction on the penis, which clears quickly with antifungal creams. Treating the male doesn't reduce the number of episodes of candidiasis in their female partner.
- Special low-sugar, low-yeast or high-yogurt diets
- Putting yogurt in the vagina
- Natural remedies (with the exception of boric acid)
On DermNet NZ:
- Cyclic vulvovaginitis
- Introduction to fungal infections
- Laboratory tests for fungal infections
- Treatment of fungal infections
- Auckland Sexual Health Service
- Thrush – spoken presentation on Bodytalk Online
- Candidiasis, Mucosal – Medscape Reference
Books about skin diseases:
See the DermNet NZ bookstore