Introduction
Normal physiological vaginal discharge is a white or clear, non-offensive discharge that can vary over time. Abnormal vaginal discharge is characterised by a change of colour, consistency, volume, and/or odour, and may be associated with symptoms such as itch, soreness, dysuria, pelvic pain, or intermenstrual or postcoital bleeding. It is most commonly caused by infection; however, there can be non-infective causes.
Causes of Abnormal Vaginal Discharge
Vaginal Infections
- Bacterial vaginosis
- Vulvovaginal candidiasis
- Trichomoniasis
Endocervical Infections
- Cervicitis caused by chlamydia or gonorrhoea
- Pelvic inflammatory disease caused by chlamydia or gonorrhoea
Non-infective Causes
- Retained foreign body (tampon, condom, vaginal sponge)
- Inflammation due to allergy or irritation
- Tumors of vulva, vagina, cervix, endometrium
- Atrophic vaginitis in postmenopausal women
- Cervical ectopy or polyps
- Fistulae
- Recent childbirth or vaginal surgery
Comparison of Vaginal Infections
| Feature | Bacterial Vaginosis | Trichomoniasis | Vaginal Candidiasis |
|---|---|---|---|
| Cause | Overgrowth of anaerobic bacteria esp. Gardnerella vaginalis | STI caused by Trichomonas vaginalis | Superficial fungal infection with Candida albicans |
| Discharge | Fishy-smelling, thin, grey/white homogeneous | Offensive smelling yellow/green frothy | White, odourless, curdy |
| Associated Symptoms | No soreness, itching or irritation | Vulval itching/soreness, dysuria, abdominal pain, dyspareunia | Vulval itching, soreness, irritation, dyspareunia, dysuria |
| Examination Findings | Thin white/grey homogeneous coating; fishy odor; no inflammation | Yellow-green frothy discharge; vulvitis/vaginitis; strawberry cervicitis | White curdy discharge; erythema; fissuring/oedema; excoriations |
| Investigations | Vaginal pH >4.5 & high vaginal swab | Vaginal pH >4.5 & high vaginal swab | High vaginal swab & fungal culture |
| Treatment | Oral metronidazole 400mg BD 5-7 days | Oral metronidazole 400mg BD 5-7 days | Intravaginal antifungal or oral antifungal ± topical imidazole |
Bacterial Vaginosis (BV)
Bacterial vaginosis (BV) is the most common cause of abnormal vaginal discharge. It is caused by an overgrowth of anaerobic bacteria, particularly Gardnerella vaginalis.
Pathophysiology
- The exact trigger for BV is unknown
- Symptoms appear when vaginal pH raises (>4.5)
- Creates alkaline environment favoring abnormal bacterial growth
- Approximately 50% of women with BV are asymptomatic
Clinical Features
- Fishy-smelling, thin, grey/white homogeneous discharge
- Not associated with itching or soreness
- Thin, white/grey homogeneous coating of vaginal walls and vulva
- Characteristic fishy odor
- No inflammation typically present
Diagnosis
Examination
- Speculum examination (except in pregnancy with low-lying placenta)
- Visualize cervix and vagina
- Look for characteristic signs
Testing
- Vaginal pH >4.5 suggestive of BV
- High vaginal swab for Gram staining
- Self-taken low vaginal swab alternative
Management
Asymptomatic Women
- Treatment not usually required
- Except if undergoing termination of pregnancy
Symptomatic Women
- Avoid vaginal douching, antiseptics, bubble baths
- First-line: Oral metronidazole 400mg BD 5-7 days
- Alternative: Intravaginal metronidazole gel 0.75% daily for 5 days
- Alternative: Intravaginal clindamycin cream 2% daily for 7 days
Complications
- Increased risk of acquiring STIs
- Association with obstetric complications
- Post-surgical infections
Trichomoniasis
Trichomoniasis is a sexually transmitted infection caused by the flagellated protozoan Trichomonas vaginalis. Vertical transmission can occur from an infected mother to baby during vaginal delivery.
Epidemiology
- Up to 50% of women are asymptomatic
- Sexually transmitted infection
- Vertical transmission possible during delivery
Clinical Features
- Frothy yellow-green offensive smelling discharge
- Vulval itching and soreness
- Dysuria or dyspareunia
- Lower abdominal pain in some cases
Diagnosis
Examination Findings
- Yellow-green, frothy discharge with offensive odour
- Inflammation of vulva and vagina
- Strawberry appearance of cervix (cervicitis)
Investigations
- High vaginal swab from posterior fornix
- Gram staining
- Vaginal pH >4.5 suggestive
- Self-taken low vaginal swab alternative
Management
Referral
Refer to genito-urinary medicine (GUM) clinic or specialist sexual health service for confirmation and treatment.
Treatment Options
- Metronidazole 400-500mg BD for 5-7 days
- Metronidazole 2g single oral dose
- Tinidazole 2g single oral dose
Partner Management
- Treat current partner(s) simultaneously
- Treat partners from previous 4 weeks
- Screen for other STIs
- Sexual abstinence for ≥1 week post-treatment
Complications
- Perinatal complications (preterm delivery, low birthweight)
- Maternal postpartum sepsis
- Facilitation of HIV transmission
- Pelvic inflammatory disease
- Increased susceptibility to bacterial vaginosis
- Increased risk of cervical cancer with HPV co-infection
- Infertility
Vulvovaginal Candidiasis
Vulvovaginal candidiasis is a symptomatic inflammation of the vagina and/or vulva caused by a superficial fungal infection, usually with Candida albicans.
Risk Factors
Medical
- Oestrogen exposure
- Immunocompromised state
- Poorly controlled diabetes mellitus
- Broad spectrum antibiotics
Lifestyle
- Local irritants
- Certain sexual behaviors
- Contraception use
- Hormone replacement therapy
Clinical Presentation
Symptoms
- Vulval itching (often defining symptom)
- Vulval soreness and irritation
- White, 'cheese-like', non-malodorous discharge
- Superficial dyspareunia
- Dysuria (external)
Signs of Severe Infection
- Erythema of vagina and vulva
- Extension to labia majora and perineum
- Vaginal fissuring and/or oedema
- Excoriation of the vulva
Diagnosis
Note: Investigations not routinely recommended if history indicates acute, uncomplicated vulvovaginal candidiasis.
When to Investigate
- Uncertain diagnosis
- Severe or recurrent symptoms
- Treatment failure
Available Tests
- Vaginal pH testing (differentiate infections)
- High vaginal swab
- Speciated fungal culture
Management
Antifungal Treatment
- Intravaginal: Clotrimazole, econazole, miconazole, fenticonazole
- Oral: Fluconazole, itraconazole
- Topical for vulval symptoms: Clotrimazole, ketoconazole
Additional Measures
- Self-care advice
- Avoid irritants
- Cotton underwear
- Proper hygiene practices
Diagnostic Approach
History Taking
- Character of discharge (color, consistency, odor)
- Associated symptoms (itch, pain, dysuria)
- Timing in relation to menstrual cycle
- Recent antibiotic use
- Contraceptive method
- Sexual history and partner symptoms
- Previous similar episodes
Examination
External Inspection
- Vulval erythema or edema
- Excoriation or fissuring
- Signs of inflammation
Speculum Examination
- Character of discharge
- Cervical appearance
- Presence of foreign bodies
- Signs of infection
Investigations
| Test | Indication | Findings |
|---|---|---|
| Vaginal pH | All cases of abnormal discharge | Normal: 3.8-4.5; BV/Trich: >4.5 |
| High Vaginal Swab | Uncertain diagnosis, treatment failure | Gram stain, culture, microscopy |
| STI Screening | Risk factors, persistent symptoms | Chlamydia, gonorrhea, trichomonas |
| Wet Mount | Suspected trichomoniasis | Motile trichomonads, clue cells |