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Managing abnormal vaginal discharge

Key learning points: There is physiological variation in vaginal discharge during the menstrual cycle. Bacterial vaginosis and candidiasis can be treated on clinical and sexual history. Bacterial vaginosis is the most common cause and can lead to pelvic inflammatory disease, pregnancy and post-termination complications
Vaginal discharge is a common reason for women to seek help from their general practice, gynaecologist, family planning service or genito-urinary clinic. The exact prevalence is unknown, as vaginal discharge is often self-diagnosed and self-treated. One telephone survey suggested that 8% of Caucasian women and 18% of Afro-Caribbean women had more than one episode of vaginal symptoms in the previous year.1 The aims of this article are to set out the nature and role of physiological vaginal discharge and the presentation, investigation, diagnosis and treatment of pathological discharge.
Physiological vaginal discharge: Leucorrhoea
In order to distinguish between physiological and pathological vaginal discharge, one must first appreciate what constitutes normal vaginal discharge. A woman may commonly have an idea of what is normal for her. Although variable, 1-4 mls of vaginal discharge is produced in 24 hours.2 The normal pH is 3.8-4.4 and it is transparent, odourless and white.3 It consists of mucous secreted from cervical glands, fluid that transudates across the vaginal walls and sloughed epithelial cells.4 The Bartholin's glands secrete small amounts of fluid. The discharge contains the normal bacterial flora of the vagina - predominantly Lactobacilli, which metabolise glycogen to lactic acid, resulting in the acidic pH.3 The role of vaginal discharge is to provide lubrication and prevent infection.4
Vaginal discharge may vary in amount and consistency, according to age, hormones (oral contraceptives, intra-uterine contraceptive devices [IUCDs] and pregnancy) and local factors.5 During the menstrual cycle, as oestrogen levels increase towards ovulation, more cervical mucous is produced and the discharge becomes clearer, wetter and stretchy to facilitate passage of sperm. As oestrogen levels fall, the discharge becomes thick and sticky again.6 
There are many causes of abnormal vaginal discharge. These can be grouped into non-infective causes, non-sexually transmitted infections and sexually transmitted infections (STIs). To determine the most likely cause, take a focused history and perform a risk assessment, appropriate questions are listed in Box 1.5,6 A sexual history is pertinent, and risk factors for STIs include age
BV may cause pregnancy complications such as late miscarriage, pre-term birth, premature rupture of membranes, low birth weight and post-partum endometritis.5 Symptomatic pregnant women should be treated.10 Women should be screened for BV prior to having a termination, to prevent endometritis and pelvic inflammatory disease (PID).10 
BV is caused by a change in the normal flora of the vagina, with reduction in Lactobacilli and overgrowth of other bacteria. It commonly presents with a characteristic offensive, fishy, white-grey vaginal discharge. There is usually no soreness, itching or irritation.10 BV can be associated with PID and signs of upper reproductive tract infection, including lower abdominal pain, fever and deep dyspareunia. If the risk of STI is low and there are no signs of pelvic infection, it is satisfactory to treat empirically for BV based on clinical suspicion, with topical or oral metronidazole. General advice includes avoiding vaginal douching and perfumed products, and to re-attend if symptoms haven't improved, as BV can recur or there could be another explanation.6,10
Vulvo-vaginal candidiasis is a fungal infection, causing copious amounts of thick, white, non-offensive 'cottage-cheese'-like discharge. Irritation, itching, soreness, dysuria and dsypareunia may accompany the discharge. On examination, there may be erythema, oedema, fissuring and excoriation. The lifetime incidence of Candidal infection is at least 75%, and 40-50% of women may have more than one episode.5 Risk factors include broad-spectrum antibiotics, pregnancy and diabetes. Asymptomatic colonisation with Candida occurs in 30-40% of pregnant women.13 Candidiasis is not associated with preterm birth or low birth weight and treatment of asymptomatic infection in pregnancy is not warranted.14 
If the presentation is uncomplicated and the risk of STI is low, it is acceptable to treat empirically with topical or oral anti-fungals (clo-trimazole/fluconazole).6 There is no evidence-based preferential route of therapy and women may choose their method of treatment.15 Oral therapy is contra-indicated in pregnancy.13 General advice includes using moisturiser as a soap substitute, avoiding tight clothing and wearing cotton underwear.13 There is no evidence that contraception, sanitary products or vaginal douching cause candidiasis.6 There is no evidence for dietary modification or oral/topical Lactobacillus, although there have been anecdotal reports.13
Recurrent vulvo-vaginal candidiasis occurs in 5% of women.13 HRT and high-oestrogen oral contraceptives may be implicated and reviewing contraception may be worthwhile. There have been reports suggesting receptive cunnilingus predisposes to recurrent candidiasis.16 Treatment involves high dose suppression therapy, followed by low dose maintenance therapy for six months.13 
Sexually transmitted infections 
Women at high risk of STIs or with signs of upper reproductive tract infection should have speculum and bimanual examinations, with triple swabs taken, including a high vaginal swab and two endocervical swabs for gonorrhoea and chlamydia.6
Once STI has been confirmed, referral to a genito-urinary clinic is recommended. Patients should be tested for co-existent STIs. Their partner should be screened and treated simultaneously and they should abstain from unprotected intercourse until treatment is complete. Trained personnel should perform contact tracing and partner notification. 
Trichomonas vaginalis (TV) may cause offensive yellow discharge, which can be frothy and profuse. It can be associated with soreness, itching, lower abdominal pain, dysuria and dyspareunia. Between 10-50% of infected women may be asymptomatic.17 It can occur concurrently with other STIs or bacterial vaginosis and 20% of women with TV have co-existent gonorrhoea.5 Treatment consists of oral metronidazole.17 
Chlamydia trachomatis may cause a copious purulent discharge due to cervicitis, or abnormal bleeding, lower abdominal pain, dysuria or dyspareunia. Around 5-10% of women under 24 years old may be infected, but up to 80% of these women are asymptomatic.6 It is the most common bacterial STI. Treatment regimens include a single dose of azithromycin, one week of doxycycline/ofloxacin or two weeks of erythromycin. Without treatment, 10-40% of women will develop pelvic inflammatory disease.18 
Neisseria gonorrhoea may present with a purulent vaginal discharge due to cervicitis, but it may be asymptomatic in up to 50%. 40% are co-infected with chlamydia.18,19 Treatment consists of a single dose of ceftriaxone (depending on microbial resistance - see local guidelines). 
In conclusion, abnormal vaginal discharge is a common and distressing condition. Many cases may be straightforward to manage on the basis of the history. Complicated presentations require examination and confirmation of the diagnosis and referral to a genito-urinary clinic may be necessary. Management includes reassurance, general advice and medication as indicated. 
1. Foxman B, et al. Frequency and response to vaginal symptoms among white and African American women: Results of a random digit dialing survey. J Womens Health 1998;7:1167-1174
3. Mylonas I, Bergauer F. Diagnosis of vaginal discharge by wet mount microscopy: A simple and underrated method. Obstet Gynecol Surv 2011; 66(6):359-68.
4. Vulvovaginal health in premenopausal women. Best Practice Journal 41 December 2011. 
5. Mitchell H. Vaginal discharge - causes, diagnosis, and treatment. BMJ 2004;29;328(7451):1306-8.
6. The management of women of reproductive age attending non-genitourinary medicine settings complaining of vaginal discharge. J Fam Plann Reprod Health Care. 2006;32(1):33-42; quiz 42.
7. Hay PE, et al. Abnormal bacterial colonization of the genital tract and subsequent preterm delivery and late miscarriage. Br Med J 1994;29; 308(6924):295-8. 
8. Blackwell AL, et al. Health gains from screening for infection of the lower genital tract in women attending for termination of pregnancy. Lancet 1993;24;342(8865):206-10.
9. McCaffrey M, Varney PA, Evans B, et al. A study of bacterial vaginosis in lesbians. Int J STD AIDS 1997;8(Suppl 1):11.
10. British Association for Sexual Health and HIV. Guideline on Management of Bacterial Vaginosis. 2012.
11. Tchamouroff SE, Panja SK. The association between receptive cunnilingus and bacterial vaginosis. Sex Transm Infect 2000;76(2):144-5.
12. Evans BA, McCormack SM, Kell PD, et al. Trends in female sexual behaviour and sexually transmitted diseases in London, 1982-1992. Genitourin Med 1995;71:286-90.
13. British Association for Sexual Health and HIV. Guideline on Management of Vulvovaginal Candidiasis. 2007.
14. Young GL, Jewell D. Topical treatment for vaginal candidiasis (thrush) in pregnancy. Cochr Database of Syst Rev 2001;(4):CD000225. 
15. Watson MC, et al. Oral versus intra-vaginal imidazole and triazole anti-fungal agents for the treatment of uncomplicated vulvovaginal candidiasis (thrush): a systematic review. BJOG 2002;109(1):85-95. 
16. Hellberg D, et al. Sexual behaviour of women with repeated episodes of vulvovaginal candidiasis. Eur J Epidemiol 1995;11:575-9.
17. British Association for Sexual Health and HIV. Guideline on Management of Trichomonas vaginalis infection. 2007. 
18. British Association for Sexual Health and HIV. Guideline on Management of Chlamydia. 2006. 
19. British Association for Sexual Health and HIV. UK National Guideline for the Management of Gonorrhoea in Adults. 2011.