Is It Thrush, BV or Something Else? A Decision Table

Thrush itches and gives a thick white discharge with little smell; bacterial vaginosis (BV) gives a thin grey-white discharge with a fishy smell and rarely itches; trichomoniasis is frothy, yellow-green and sore; cystitis is a bladder problem, with stinging when you pee and no discharge. In practice, when 95 women buying an over-the-counter thrush treatment were examined, 34% had thrush alone, 19% BV alone, 21% both and 14% nothing wrong.^{1, 2} The misses that cost years are not infections: lichen sclerosus, atrophy after the menopause, an allergy to the cream itself. This is the symptom spoke of the Wellgard guide to what causes BV.

Sources checked on 29 October 2026.

Is it thrush, BV or something else? The decision table

How can you tell if it's thrush?

By the itch more than the discharge. In a review of diagnostic studies, no single symptom confirmed any cause, but no itching made thrush less likely and no smell made BV unlikely.² The NHS lets a pharmacist sell an antifungal to a woman who has had thrush diagnosed before, and not more than twice in six months without advice.¹ A second pack inside six months means asking a pharmacist or doctor. Vaginal thrush: symptoms, causes and treatment covers the condition and its triggers.

What is usually mistaken for BV, and what does BV get mistaken for?

BV is mistaken for thrush far more often than the other way round: in the thrush-aisle study, BV or a mixed picture accounted for 40% of the women.² BV is also mistaken for poor hygiene, for an STI (it is neither) and for ordinary smells: semen, sweat, the first day of a period and urine leakage each have a smell, none fishy. "How do I know if I have BV or just a smell?" A thin grey discharge with a smell that is worst after sex fits the NHS description of BV; a smell that comes and goes with sweat or the end of a period, with no change in discharge, does not.³ What your discharge means takes each sign in turn.

How do I know if it's BV or trichomoniasis?

Often you cannot without a swab. Trichomoniasis is a sexually transmitted parasite; the NHS describes a yellow-green discharge that may be frothy or fishy, with itching, soreness, swelling and pain when you pee or have sex.⁴ The two travel together: in a 2021 meta-analysis of 12 studies, women with BV were about 1.9 times as likely to acquire trichomoniasis.⁹ A sexual health clinic tests for both from one swab, and for trichomoniasis current and recent partners need treatment too.⁴

How can I tell the difference between BV, thrush and a UTI?

By where it hurts. Cystitis is a bladder infection: burning as you pee, going often and urgently, lower tummy ache, and no vaginal discharge.⁵ Thrush stings as urine passes over sore skin and is read as cystitis; the giveaway is itch and discharge. BV gives discharge and smell with no urinary symptoms. The UTI red flags: a high or very low temperature or shivering, pain in the back under the ribs, blood in the urine, pregnancy, or no improvement within 48 hours mean an urgent GP appointment or 111, and confusion or drowsiness means 999.⁵ Cystitis: everything you need to know covers the rest and how long a UTI lasts and what settles it the wait.

What could be mistaken for thrush when it isn't an infection at all?

Four things. Vaginal atrophy (genitourinary syndrome of menopause): falling oestrogen thins the vaginal skin, giving dryness, burning, soreness, pain during sex and repeated UTIs; it can start in perimenopause, and no antifungal helps it.⁶ Vaginal health after the menopause covers it. Lichen sclerosus: an inflammatory skin condition with a relentless itch and white smooth or crinkled patches that tear; the NHS says it cannot be cured but a prescription steroid ointment usually relieves it; because it slightly raises the risk of vulval cancer it is checked regularly.⁷ Contact dermatitis: the vulval skin reacts to a wipe, a pad, a wash or the antifungal cream itself, so each treatment makes the itch worse; the test is to stop everything but water and an emollient. Cytolytic vaginosis: a contested diagnosis in which lactobacilli are over-abundant and the discharge is white and itchy, so it mimics thrush but swabs are negative; a 2023 review found it in about 5% of women with vaginal symptoms, with no agreed treatment.⁸ A negative swab is information, not a dead end; sometimes it is normal discharge through the cycle.

When should I stop self-treating and see a GP or sexual health clinic?

When thrush treatment has not worked within a week, or you have needed it twice in six months.¹ For a first episode. For bleeding between periods, after sex or after the menopause. For sores, blisters, white patches, splits or any skin change. For pelvic pain, fever or pain during sex. For symptoms in pregnancy. For a new partner, with an STI test. For BV more than four times a year. And for a smell that does not go. Sexual health clinics need no referral, and the NHS says not to self-diagnose.^{3, 10}

How do a swab, pH test and culture settle it?

A clinician looks, dips a pH strip into the discharge (BV and trichomoniasis push the pH above 4.5; thrush and cytolytic vaginosis leave it low) and puts a drop under the microscope: clue cells mean BV, yeast cells and threads mean thrush, moving parasites mean trichomoniasis, and sheets of lactobacilli with fragmented cells suggest cytolytic vaginosis.^{2, 8} The same review concluded that microscopy, not the story, is the most useful way to diagnose the three infections;² how a BV test is done has the detail.

What we don't know

No UK study has repeated the thrush-aisle count; the 95-woman sample is American.² Cytolytic vaginosis has no agreed diagnostic criteria or tested treatment.⁸ No study has measured how long UK women with lichen sclerosus or atrophy wait, labelled as thrush, before the right diagnosis.

Frequently asked questions

What happens if you use a thrush cream but you have BV?

Nothing useful: antifungals do not act on bacteria, so the discharge and smell carry on and the cream can irritate. Antibiotics for BV are prescription-only; how BV is treated in the UK covers the routes.

What smells like BV but isn't BV?

Trichomoniasis, a retained tampon (a far stronger, foul smell), semen for a day after sex, the end of a period, and urine leakage after the menopause.^{3, 4}

Can you have BV and thrush at the same time, and can you treat both together?

Yes. In a study of 1,740 women with symptoms, one in five had two of BV, thrush and trichomoniasis at once.¹¹ A swab settles which is present; a GP or sexual health clinic can prescribe the antibiotic and the antifungal together.

What is the treatment for an infection "down there"?

It depends which one: an antifungal pessary, cream or tablet for thrush; a prescription antibiotic for BV and trichomoniasis; steroid ointment for lichen sclerosus; vaginal oestrogen for atrophy. No single product covers them; the diagnosis comes first.^{1, 3, 4, 5, 7}

Sources

1. NHS. Thrush in men and women. Reviewed 28 July 2023. nhs.uk/conditions/thrush-in-men-and-women.
2. Ferris DG, et al. Over-the-counter antifungal drug misuse associated with patient-diagnosed vulvovaginal candidiasis. Obstetrics and Gynecology, 2002. Cross-sectional, 95 women. PubMed 11864668; Anderson MR, Klink K, Cohrssen A. Evaluation of vaginal complaints. JAMA, 2004. Diagnostic review. PubMed 15026404.
3. NHS. Bacterial vaginosis. Reviewed 19 June 2026. nhs.uk/conditions/bacterial-vaginosis.
4. NHS. Trichomoniasis. Reviewed 16 July 2025. nhs.uk/conditions/trichomoniasis.
5. NHS. Urinary tract infections (UTIs). Reviewed 11 July 2025. nhs.uk/conditions/urinary-tract-infections-utis.
6. Portman DJ, Gass MLS. Genitourinary syndrome of menopause: new terminology for vulvovaginal atrophy. Menopause, 2014. Consensus statement. PubMed 25160739.
7. NHS. Lichen sclerosus. Reviewed 9 December 2024. nhs.uk/conditions/lichen-sclerosus.
8. Kraut R, et al. Scoping review of cytolytic vaginosis literature. PLoS One, 2023. Scoping review. PubMed 36701339.
9. Seña AC, et al. Bacterial vaginosis and its association with incident Trichomonas vaginalis infections: a systematic review and meta-analysis. Sexually Transmitted Diseases, 2021. Meta-analysis, 18,424 women. PubMed 34433796.
10. NHS. Vaginal discharge. Reviewed 15 February 2024. nhs.uk/conditions/vaginal-discharge.
11. Gaydos CA, et al. Clinical validation of a test for the diagnosis of vaginitis. Obstetrics and Gynecology, 2017. Manufacturer-involved validation study, 1,740 women. PubMed 28594779.

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This article is general information, not medical advice. A first episode, treatment that has not worked, bleeding, skin changes, pain, fever, pregnancy or symptoms over 50 mean a GP or sexual health clinic rather than self-treatment.