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The common vaginal infection thrush can make life "hell" for millions of women worldwide, particularly if it keeps coming back, scientists are warning.

According to University of Manchester research, recurrent thrush is a growing problem which can feel "like torture" if it isn't treated.

Three out of four women are thought to develop thrush at least once and 6% suffer repeatedly, scientists say.

More than a million women in the UK are affected by the painful infection.

But for many women it is a taboo subject, says Dr Riina Rautemaa-Richardson, clinician and lead Manchester researcher of a review in The Lancet Infectious Diseases.

"Thrush is often thought of as an embarrassing problem women should accept, rather than a medical problem which needs to be dealt with.

"But for millions of women, it can have a massive impact on their quality of life."

Marriage wrecker

She says the itching, pain and discomfort of chronic thrush can make women feel neurotic and desperate.

For some, it causes a serious loss of confidence which can make exercise and sex very difficult.

Dr Rautemaa-Richardson says it can affect absolutely every aspect of a woman's life.

"They say, 'Life is hell', 'I can't go on holiday because of it' and 'I can't do this or that'.

"Female patients have told me I saved their marriage by getting rid of thrush."

Most cases occur in women aged 25 to 34, but a growing female population using hormonal replacement therapy (HRT) - to alleviate menopause symptoms and improve sexual experience - is thought to be behind the rise in the numbers affected.

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Thrush symptoms in women:

white discharge (like cottage cheese), which doesn't usually smell

itching and irritation around the vagina

soreness and stinging during sex or when you pee

Thrush can affect other areas of skin, such as the armpits, groin and between the fingers, causing a red, itchy or painful rash.

Sometimes thrush causes no symptoms at all.

Source: NHS Choices

Why does thrush occur?

Vulvovaginal candidiasis - known as thrush - is caused by the overgrowth of the fungus candida.

It often arises in the week before a period starts and is most common in sexually active women taking the pill or those on HRT or antibiotics.

There are other causes for vaginal itching, such as eczema, so women should be properly examined before starting treatment.

Why does it come back?

Although thrush is treatable, using over-the-counter tablets, creams and pessaries, it often returns and can become a chronic problem which won't go away.

In some cases, after 20 or 30 episodes, the infection can become resistant to standard drugs, leaving women with few treatment options.

Special infection centres can provide treatment even if your own GP cannot.

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Does yoghurt really work?

Dr Riina Rautemaa-Richardson says there isn't any scientific evidence that putting yoghurt on vaginal thrush makes it go away.

But it could have a cooling effect - and is likely to be more beneficial for thrush on the tongue.

The yoghurt must contain live bacteria to work.

Any other myths?