Candida albicans or thrush is an ubiquitous yeast-like fungus that is commonly carried as a commensal. It is present in the vaginas of 20% of women with no symptoms. Predisposing factors include diabetes (therefore exclude glycosuria), pregnancy, broad-spectrum antibiotic treatment, steroid treatment, and immunodeficiency as in AIDS. Contrary to popular opinion, the low-dose oral contraceptive pill is not a cause of thrush and the pill should not be discontinued for this reason alone. Although vaginal candidiasis in healthy women does not result in serious complications, it can cause considerable distress. In addition, in the lay press thrush has been blamed (with little scientific evidence) for a multitude of symptoms including those often attributed to irritable bowel syndrome.
Symptoms and signs
Candida may cause itching and soreness of vulva and vagina leading to dysuria and dyspareunia. However, it can improve spontaneously, and often causes no symptoms. On examination, the vagina and vulva may be inflamed and oedematous, and fissures can occur. The typical discharge is white or yellow, like cottage cheese, but clinical examination is notoriously unreliable for diagnosis.
This is by culture and microscopy of a high vaginal or cervical swab. Candida may occasionally be diagnosed on cervical cytology. However, most women in stable partnerships who have had microbiologically diagnosed thrush previously will not need swabs unless their symptoms fail to improve on treatment.
This is only required for symptomatic candida. Topical or oral treatments are both 80 – 90% effective in uncomplicated candida, but topical treatment is cheaper and less toxic. Common regimens are:
- clotrimazole pessaries 200 mg per vaginam nocte for 3 nights or 500 mg for one night; or
- fluconazole 150 mg orally as a single dose. This is contraindicated in pregnancy or lactation.
Additional creams containing steroid, e.g. clotrimazole with hydrocortisone, are useful for local irritation. All these treatments are available over the counter.
Ideally “thrush” should only be treated blind on one occasion before being investigated, and then only in low-risk women who will return if symptoms persist. Many women with so-called “recurrent candida” do not have candida at all. Therefore clinical examination and full microbiological tests are essential. The patient may have bacterial vaginosis, herpes, or dermatological conditions such as eczema, lichen planus, or lichen sclerosis. There may be psychosexual problems and some women may use their symptoms as an excuse to avoid sexual intercourse.
Management of women with proven recurrent vaginal candidiasis can be difficult. They should be advised to use emollients, not to wash excessively, and to avoid vaginal deodorants, bubble baths, and other additives such as dettol and TCP. KY jelly can be used to reduce trauma during sexual intercourse. Loose clothing is recommended. Two-week courses of clotrimazole pessaries 100 mg nocte or oral fluconazole 50 mg daily may be effective. Unfortunately, oral treatment is no more likely than topical treatment to prevent relapse. If thrush occurs premenstrually, pessaries can be used prophylactically. Partners should be treated if symptomatic. There is little evidence that yoghourt, either orally or vaginally, is effective, but some patients find local application soothing. Self-help books and complementary therapies may be useful.
Bacterial vaginosis is due to an overgrowth of Gardnerella vaginalis and mixed anaerobes. It is the commonest cause of abnormal vaginal discharge in women of child-bearing age. It is not generally regarded as a sexually transmitted infection although its prevalence increases with increasing sexual activity.
Symptoms and signs
Bacterial vaginosis has a characteristic fishy smell because of the production of diamines. The smell is worse after sexual intercourse and may be associated with a watery, grey, offensive discharge. It causes little irritation and up to 50% of women with bacterial vaginosis have no symptoms.
In general practice this is usually by culture and microscopy of a high vaginal or cervical swab. Clue cells – vaginal epitheliel cells covered with adherent bacteria – may be seen on a wet mount of vaginal fluid.
There is no absolute indication to treat healthy asymptomatic women with bacterial vaginosis. For those complaining of smelly vaginal discharge, a 90% cure rate is produced by:
- metronidazole orally 400 mg b.d. for 5 days or a single dose of 2 g orally. (Metronidazole is contraindicated in the first trimester of pregnancy, and patients should be advised to avoid alcohol because of the Antabuse-like effect.)
- alternatively, clindamycin 2% cream, one 5 g application may be inserted per vaginam nightly for 7 nights.
If initial treatment is unsuccessful, the alternative treatment may be tried. In resistant cases oral clindamycin 300 mg b.d. for one week is occasionally used. Treatment of the male partner has not been shown to increase cure rate or reduce recurrence, but is probably worthwhile in women with recurrent bacterial vaginosis.
Table Diagnosis and management of infective causes of vaginal discharge