Around 90% of vaginitis is caused by infection, mainly bacterial vaginosis, vulvovaginal candidiasis, and trichomoniasis.[4] These 3 diagnoses should be excluded in all patients before considering other less common causes.

Clinical history and examination

In a patient presenting with a complaint of ongoing vaginal discharge, the initial history should include:

  • Any new sexual partners

  • Use of new soaps or detergents

  • Use of feminine hygiene products (e.g., douches, wipes, sprays)

  • Contraceptive vaginal ring or intrauterine device use

  • Previous therapies

  • Symptoms such as pelvic pain, itching, quality/quantity/odour of discharge.

Bacterial vaginosis typically presents with a thin discharge and fishy odour ('whiff test'). Trichomoniasis presents with a purulent malodorous discharge. Vulvovaginal candidiasis presents with a white, cottage cheese discharge and pruritus.

A physical examination should include visualisation of the vulva, vagina, and cervix in search of lesions and/or erythema, and a bimanual examination to evaluate for pelvic mass or cervical motion tenderness.

In symptomatic women, self-obtained swabs and history alone may not be as useful as physical assessment and speculum exam by a clinician.[54]

Routine investigation

A sample of vaginal discharge should be obtained and pH elucidated using litmus paper. Wet mount microscopy is performed by placing a small sample of discharge on 2 separate areas in a slide and adding normal saline to 1 area and potassium hydroxide to the second. A cover slip is then placed on the slide, which is then visualised with a microscope.

The patient should be counselled and treated appropriately if the wet mount confirms any of the following:

  • Amsel's criteria, 3 out of 4 of: homogeneous vaginal discharge; positive whiff test with addition of 10% potassium hydroxide; clue cells; and pH >4.5 (bacterial vaginosis).com.bmj.content.model.assessment.Caption@5a316a3c[Figure caption and citation for the preceding image starts]: Photomicrograph revealing bacteria adhering to vaginal epithelial cells, known as clue cellsCDC Image Library; M. Rein [Citation ends].

  • Trichomonads (51% to 65% sensitive for trichomoniasis[23]).com.bmj.content.model.assessment.Caption@717f4b0e[Figure caption and citation for the preceding image starts]: Trichomonasvaginitis with copious purulent discharge emanating from the cervical os CDC Image Library [Citation ends].com.bmj.content.model.assessment.Caption@a332cae[Figure caption and citation for the preceding image starts]: Phase contrast wet mount micrograph of a vaginal discharge revealing the presence of Trichomonas vaginalisprotozoa CDC Image Library [Citation ends].

  • Budding yeast and hyphae (candidiasis).com.bmj.content.model.assessment.Caption@6f6cb8fd[Figure caption and citation for the preceding image starts]: Vaginal smear identifying Candida albicans using Gram stain technique CDC Image Library; Dr Stuart Brown [Citation ends].com.bmj.content.model.assessment.Caption@3e5d4fa6[Figure caption and citation for the preceding image starts]: Vaginal smear identifying Candida albicans using a wet mount technique CDC Image Library; Dr Stuart Brown [Citation ends].

  • White blood cells without trichomonads or yeast (may suggest cervicitis[23]).

Alternative or supplementary tests include the following:

  • Vaginal culture with sensitivities for vulvovaginal candidiasis: should be obtained to confirm diagnosis in patients with typical clinical features but normal vaginal pH and negative wet mount microscopy. Should also be obtained for patients with recurrent symptoms and multiple failed therapies.

  • Vaginal assays for trichomoniasis: should be considered if pH is >4.5, if there are high polymorphonuclear leukocytes but no motile trichomonads on wet mount microscopy, or if microscopy is not available.

  • Gram stain to determine the relative concentration of lactobacilli: considered by some to be the best test for diagnosing bacterial vaginosis.[23] A Gram stain can be evaluated by the Nugent criteria or the Hay-Ison criteria. The Nugent criteria report the relative proportions of the different bacterial morphotypes. The Hay-Ison criteria are graded: 0 for only epithelial cells; 1 for mostly Lactobacillus; 2 for mixed flora; 3 for predominantly Gardnerella and/or Mobiluncus; and 4 for aerobic vaginitis with mostly aerobic bacteria. The British Association for Sexual Health and HIV recommends using the Hay-Ison criteria over the Nugent criteria.[15]

Nucleic acid amplification tests and nucleic acid probes are available for the detection of bacterial vaginosis, Candida, and trichomoniasis. The nucleic acid amplification tests appear to be more accurate but all of these tests are expensive; therefore, they should typically be reserved for areas of high prevalence or where wet mount microscopy or cultures are not available.

Women at risk for sexually transmitted infections

In women at risk for sexually transmitted infections (those with new, multiple partners, or partners with multiple partners, as well as women younger than 25 years old) and profuse yellowish vaginal discharge, a pelvic examination should be performed and assays for Neisseria gonorrhoeae and Chlamydia trachomatis obtained. Mycoplasma genitalium testing may be considered in women with persistent or recurrent symptoms.[55][34] These women should also be tested for Trichomonas vaginalis.

If the discharge is accompanied by pelvic pain and/or cervical motion tenderness, the patient should be treated for pelvic inflammatory disease (PID) according to local guidelines. Treatment of N gonorrhoeae, C trachomatis, and suspected PID should prevent infertility and chronic pelvic pain.

Recurrent vaginal discharge

If the patient presents with recurrent vaginal discharge, other diagnoses should be considered, including recurrent vulvovaginal candidiasis. Patients with recurrent vulvovaginal candidiasis should have the following excluded: diabetes mellitus; immunocompromised states such as HIV; other type of Candida (e.g., Candida glabrata), because they can be resistant to antifungal agents used in the management of Candida albicans.

Normal examination and negative results

Patients with vaginal discharge, an unremarkable examination, negative assays, and a history concordant with possible irritants (e.g., change in soap or detergents) have allergic vaginitis. This typically resolves with avoidance of the irritant. Poor hygiene must be considered in those with negative assays and no history of contact irritants: for example, patients who don't change tampons regularly or wash appropriately (wiping back to front).

Patients with isolated vaginal discharge of normal colour, odour, and consistency and who have a normal pelvic examination and wet mount can be reassured that the vaginal discharge is of the physiological type.

Uncommon causes

Less common and very unusual causes of vaginal discharge should be ruled out by appropriate tests and studies once more common causes have been excluded clinically and/or by investigation.

Atrophic vaginitis

  • If the woman is postmenopausal and the vaginal epithelium appears pale, smooth, and shiny, then clinical diagnosis of atrophic vaginitis may be considered.

  • Microscopy reveals abundant white blood cells, parabasal cells, and absent infectious pathogens. Papanicolaou smear can confirm the diagnosis.

Physiological postpuerperal atrophic vaginitis

  • History of recent child birth with characteristic discharge (lochia rubra, serosa, or alba) is diagnostic.

Herpes simplex virus

  • Multiple crops of painful, shallow ulcers may indicate herpes simplex virus cervicitis, which can be confirmed with viral cultures and nucleic acid assays. Tzanck stain is of historical interest, but guidelines do not support its use in diagnosis.[23]com.bmj.content.model.assessment.Caption@35f14458[Figure caption and citation for the preceding image starts]: Presence of herpes simplex virus in a Tzanck test specimenCDC Image Library; Joe Miller [Citation ends].

Foreign body

  • Presents with malodorous discharge and irritation, and, if longstanding, can lead to extensive adhesion formation with near complete obstruction of the vagina inferior to the location of the foreign body.[52]

  • Diagnosis may be confirmed with a pelvic examination, pelvic x-ray, transvaginal/transabdominal ultrasound, and/or contrast pelvic MRI.

Behcet's syndrome

  • Will present with other features of the syndrome (e.g., aphthous ulcers, skin lesions, and uveitis) in addition to vaginal ulceration and discharge. Typically diagnosed clinically.

Desquamative inflammatory vaginitis (DIV)

  • Associated with purulent and copious discharge, severe dyspareunia, or minor vulvar symptoms such as irritation and/or pruritus; may indicate diagnosis of inflammatory vaginitis.

  • Wet mount excludes infective cause and shows an abundance of polymorphonuclear leukocytes. Parabasal cells are often found.

  • Vaginal biopsy demonstrates features of acute and chronic inflammatory reaction of stroma with capillary dilatation.

  • Colposcopy may be utilised to aid diagnosis if there is uncertainty.

Lichen planus

  • May be difficult to distinguish from atrophic vaginitis if there are no extravaginal symptoms.

  • Presents with shiny papules, which are typically intensely itchy. Biopsy of vaginal wall confirms diagnosis.

Streptococcal vaginitis in adults

  • Predisposing factors include household or personal history of an upper respiratory tract infection with group A streptococci, sexual contact, or vaginal atrophy. Vaginal discharge is profuse or copious. Diagnosis is confirmed with culture.[38]

Genital schistosomiasis

  • Has been described in Africa; characterised by copious vaginal discharge and an erythematous cervix. Diagnosis is made by microscopic detection of parasitic eggs in urine, followed by cervical punch biopsy.[39] Punch biopsy has 100% sensitivity for schistosomiasis but can increase HIV transmission due to breakdown of the mucosal barrier, therefore the risk and benefits of punch biopsy need to be carefully weighed. High-magnification colposcopy may also be used for diagnosis.[56]

Entamoeba gingivalis

  • Has been associated with oral infection and intrauterine device use in Egypt.[40]


  • Prior history of intravaginal slingplasty with onset of purulent and offensive vaginal discharge suggests postsurgical (rare) vaginitis and can be confirmed with contrast MRI. In April 2019, the US Food and Drug Administration prohibited sales and distribution of surgical mesh intended for transvaginal repair of anterior compartment prolapse (cystocele).[43] In the UK, the use of surgical mesh/tape for urogynaecological prolapse, where the mesh is inserted through the vaginal wall, is currently restricted while an independent review takes place. In July 2018, NHS England advised that all cases should be postponed if it is clinically safe to do so.[47][45] Other less common causes of vaginal discharge reported in the literature include prolapsing fibroid[48] and vaginal fistula.[49]


  • History of radiation therapy; vaginal atrophy may be present.[41]

Cervical cancer

  • An older patient presenting with foul-smelling discharge and a cervical mass on examination should have a biopsy of the mass, and consideration of a Pap smear and CT scan of the abdomen and pelvis to rule out cervical cancer.

Carcinoma of the fallopian tube

  • Rare, and only 16% of patients present with the classic triad of vaginal discharge, colicky pelvic pain, and palpable pelvic mass, although data are very limited.[57]

  • Pelvic ultrasound and CA-125 may aid diagnosis, but surgical staging is definitive.

Lymphoma of genital tract

  • Very rare cause of vaginal discharge. Patients may present with mass, malodorous discharge or vaginal bleeding, or abdominal pain or fullness. A mass may be palpated on bimanual examination or visualised on speculum examination.[58][59]

Paediatric patients

In the paediatric population, foreign body and sexual abuse should always be ruled out clinically, and if necessary by history and physical exam, vaginal swabs, transabdominal pelvic ultrasound, vaginoscopy, and referral to a child abuse specialist.

Other diagnoses and investigations include the following:

  • Microscopy of vaginal sample demonstrates sheets of vaginal epithelium in physiological leucorrhoea.

  • Recent history of pharyngitis and signs of vaginal infection suggest streptococcal vaginitis, which is confirmed with vaginal swabs for streptococcal organisms.

  • Babies under 1 year old with vaginal symptoms may have been infected by the mother in the birth canal. Vaginal and cervical swabs of the mother confirm this.

  • If there is a history of use of bubble baths, perfumed soaps, tight-fitting clothes, or back-to-front wiping, then diagnosis of non-specific vaginitis is clinical.

  • Pinworms may be suspected if there is nocturnal discomfort or pruritus. Cellophane tape testing confirms the[Figure caption and citation for the preceding image starts]: Enterobius vermicularis egg (human pinworm) CDC Image Library [Citation ends].

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