Thrush and bacterial vaginosis (BV) are common vaginal infections that can cause symptoms including abnormal discharge.
They are also both easily treatable, but Deborah Bateson says because there is less awareness around BV, people may be reaching for the wrong treatment option.
She's a professor of practice at the University of Sydney's faculty of medicine and health.
"Sometimes we know women might just be going to the chemist to get short courses of treatment, which can be quite helpful," Professor Bateson says.
"But if it's the wrong diagnosis, it won't work."
We explain the similarities — and differences — between the two conditions, to help people better identify what might be going on for them.
What is vaginal thrush?
Thrush (vaginal candidiasis) is a yeast infection, caused by a yeast called candida.
Professor Bateson says candida is a usually harmless fungus found in low amounts on genital skin and in the vagina.
It can also be found in the bowel and other parts of the body.
"You get [thrush] symptoms because of an overgrowth of that candida yeast," Professor Bateson says.
About three in four people with a vagina will experience thrush in their lifetime.
Symptoms can include a thick, white discharge, commonly described as a "cottage cheese" consistency, says Professor Bateson.
There may also be burning, itching, redness, and swelling of the vulva and vagina.
Thrush may have a mild, yeasty smell, but typically isn't associated with a strong odour.
Professor Bateson says thrush can be triggered by taking antibiotics and hormonal changes.
"Thrush thrives in conditions where there is high estrogen, so certainly in pregnancy, and people taking oral contraception with estrogen."
She says people with chronic health conditions such as diabetes, or those taking immune-regulating drugs, may also experience more frequent occurrences of thrush.
What is bacterial vaginosis (BV)?
Bacterial vaginosis is caused by an imbalance of bacteria in the vagina, explains Pav Nanayakkara, a gynaecologist at Jean Hailes for Women's Health.
"Typically it's bacteria that would normally be living in the vagina, but some become overgrown."
She says anaerobic bacteria outnumbers the lactobacilli bacteria (which are normally found in the vagina and help maintain vaginal health).
One in three people with a vagina will experience BV in their lifetime.
Dr Nanayakkara says discharge associated with BV is thin, watery and greyish.
While there can be some mild irritation, itching and burning is less likely than with thrush.
An unpleasant odour associated with BV is one of the key differences in symptoms, says Professor Bateson.
"Sometimes we call it a fishy smell — that's because of that change in the microbiome.
"This can be so stigmatising, can cause real distress, and a fear other people are noticing it."
Dr Nanayakkara says BV can be triggered by new sexual partners, vaginal douching, and putting things inside the vagina.
Quick ways to spot the difference
Discharge
Thick and white like "cottage cheese" — thrush
Discharge thin, watery and grey – BV.
Irritation
Burning, itching, stinging, redness, swelling — thrush.
Mild or no irritation — BV.
Smell
No smell or mild yeast odour — thrush
Strong fishy, unpleasant smell — BV.
It's important to note that some of the symptoms associated with thrush and BV can also be a sign of other conditions such as sexually transmitted infections or hormonal changes, Professor Bateson says.
It's important to see your doctor to get a diagnosis if you are unsure, or experiencing recurring issues.
Are thrush or bacterial vaginosis dangerous?
Neither thrush or BV are dangerous, Professor Bateson says, but both can cause some distress and reduced quality of life.
BV left untreated, however, can increase someone's risk of:
• catching and transmitting sexually transmitted infections
• pelvic inflammatory disease
• miscarriage
• premature birth
• low birth weight.
"That's why it's important to treat it," Professor Bateson says.
Prevention and treatment options
Vaginal hygiene practices can act as preventative measures for both thrush and BV, says Professor Bateson.
"Wiping front to back [after going to the toilet], don't use anything perfumed on the vagina, avoid tight, synthetic underwear, and changing underwear after sweaty activity.
"It needs breathing space."
Over-the-counter treatments for thrush include creams, pessaries and oral medication — some of which are used over one, three, or up to seven days.
For recurring thrush, Professor Bateson says it's important to see your doctor as you may require longer treatment.
"If thrush is inadequately treated it will just keep being recurrent.
"Sometimes a doctor will take a swab and send off to lab because it might be a different kind of candida that requires different medication."
For BV, people will need to see their doctor to be diagnosed and be prescribed an antibiotic.
"It's typically a tablet but we can also use gels for BV as well," says Dr Nanayakkara.
New research shows BV can be wiped out in many cases if the male partner of women is treated too.
"There was a lot of evidence clinically and anecdotally that BV was being acquired from new partners, and recurrence was being driven by ongoing exposure to untreated partners," said study co-author Catriona Bradshaw, a sexual health physician at Melbourne's Alfred Health and researcher at Monash University.
Dr Nanayakkara says both thrush and BV are common and there is no reason to feel ashamed about having either condition.
"There is no need for embarrassment when it comes to this stuff.
"They are very, very common."
This is general information only. For personal advice, you should see a qualified medical practitioner.
