13, Oct, 2025

STIs vs Thrush vs BV: How to Tell What Is Really Going On

Itching, soreness, odd discharge or a change in smell can be worrying. Many people immediately think of sexually transmitted infections. In reality, common vaginal conditions like thrush and bacterial vaginosis are just as likely, and they often present with overlapping symptoms. Knowing the key differences helps you decide when self care is reasonable, when pharmacy treatment can help, and when it is time to book an STI screen.

Quick definitions

Thrush
A yeast overgrowth, usually caused by Candida. It is not classed as an STI, although sex can sometimes trigger symptoms by upsetting the natural balance.

Bacterial vaginosis
Often called BV. Caused by a change in the vaginal microbiome with a drop in protective lactobacilli. Not an STI, but sex and new partners can increase the chance of BV recurring.

Sexually transmitted infections
Infections such as chlamydia, gonorrhoea, trichomonas, syphilis and herpes that are passed through sexual contact. Some cause few or no symptoms.

👉 If you want clarity without guesswork, arrange a confidential screen with STI Clinic.

Typical symptoms and clues

Thrush clues

Intense itching and soreness around the vulva
Thick white discharge that looks like cottage cheese and usually has little or no smell
Stinging or burning when urinating if the skin is sore
Pain during sex due to irritation
Thrush often flares after antibiotics, during pregnancy, or with tight clothing and heat. It can affect anyone with a vagina, regardless of sexual activity.

BV clues

Thin, grey or off white discharge
Noticeable fishy smell that may be stronger after sex or during periods
Mild irritation but usually less itching than thrush
BV is linked to a disrupted microbiome. Douching and scented washes can make it worse. Recurrence is common, and it can happen even if you are not sexually active.

STI clues

Unusual discharge that may be yellow, green or blood stained
Pain or burning when passing urine
Bleeding after sex or between periods
Pelvic or lower abdominal pain
Genital sores, blisters or warts
Sore throat after oral sex
Keep in mind that many STIs cause no symptoms at all. That is why testing matters.

Can you have more than one problem at once

Yes. A person can have BV and an STI, or thrush and an STI, at the same time. Symptoms can blur together, which is why self diagnosis is difficult. If you have a new partner, unprotected sex, or symptoms that do not match thrush neatly, plan an STI screen.

👉 Not sure which tests to choose? Get tailored advice at STI Clinic.

What helps in the short term

For likely thrush
Over the counter antifungal treatments can help. Avoid scented products and allow airflow with breathable underwear. If you are not better within a few days, or symptoms recur frequently, seek medical advice and consider testing.
For likely BV
Avoid douching and perfumed washes. BV usually needs prescription or pharmacy supplied antibiotics or antiseptics. If symptoms keep coming back, speak to a clinician and consider screening for STIs as part of the assessment.
If you suspect an STI or have a new partner
Book a test rather than guessing. Avoid sex or use condoms until you have results. Early diagnosis prevents complications and protects partners.

When to test for STIs

Plan a screen if any of the following apply:

You have had unprotected sex with a new partner
You notice bleeding after sex or between periods
You have lower abdominal or pelvic pain
You have sores, blisters or unusual rashes
Symptoms do not settle with appropriate thrush or BV treatment
You prefer certainty

Testing is quick and discreet. Many results are available within a few days, and most bacterial infections are easy to treat when found early.

👉 Book a confidential test today with STI Clinic.

What about partners

Thrush is not usually passed on, so partner treatment is seldom needed. BV is not classed as an STI, but symptoms can recur with partner changes, so condoms may help during treatment. For STIs, partners often need testing and treatment to prevent ping pong transmission. Your clinician can help with confidential partner notification.

Prevention tips that actually work

Use condoms consistently, including for oral sex if you are concerned about throat infections
Skip scented washes and douching to protect the vaginal microbiome
Choose breathable underwear and change out of sweaty clothing quickly
Clean or cover sex toys with a fresh condom between partners or body sites
Plan routine STI screens, for example yearly, or every three to six months if you have new or multiple partners
Consider vaccination where eligible, such as HPV and hepatitis B

Speak to Our Specialist

Confused about your symptoms? Chat with our sexual health experts in London for professional advice and tailored treatment options. Your health matters—get clarity today.

The practical takeaway

Thrush tends to itch and looks like thick white discharge with little smell. BV tends to have a fishy odour with thin discharge and less itching. STIs can present with discharge, pain when urinating, bleeding after sex, pelvic pain or sores, but they can also be silent. Because symptoms overlap, testing takes the guesswork out of the situation and allows the right treatment first time.

If in doubt, test. It protects your health, protects your partner and saves weeks of uncertainty.

👉 Ready for clear answers and fast results? Book your STI screen with STI Clinic.