Vaginal thrush

Thrush is an overgrowth of a yeast, almost always Candida albicans. The yeast lives harmlessly in and on a great many people; thrush is what happens when it multiplies beyond the point the body keeps it in check. It occurs in the mouth, in skin folds and under nappies as well, but this article is about the vaginal and vulval form.

It is extremely common — roughly three-quarters of women have at least one episode, and something like four in ten have more than one. It is not a sexually transmitted infection, and a partner without symptoms does not need treating.

Two things are worth establishing before the rest of it, because both are widely got wrong.

Candida is a yeast, not a bacterium, which is why antibiotics do not treat it and why taking antibiotics for something else is one of the commoner things that brings it on.

The vagina is acidic, not neutral. Its normal pH sits somewhere around 3.8 to 4.5, maintained by resident lactobacilli, and that acidity is part of what keeps other organisms in their place. Advice built on the idea of restoring a neutral balance is working from the wrong figure.

What it feels like

Itching, soreness and irritation of the vulva, usually the most prominent feature. A thick white discharge, often likened to cottage cheese, which characteristically does not smell. Stinging on passing water, discomfort during sex, and sometimes small splits in the skin, redness and swelling.

The discharge is not always typical and is sometimes absent altogether, which is part of why thrush is hard to diagnose on symptoms alone.

What else produces the same symptoms

This is the most useful section here, because a large proportion of people who treat themselves for thrush do not have thrush. Itching and discharge are produced by several quite different things, and the wrong treatment simply delays the right one.

• Bacterial vaginosis. The commonest alternative. A thin, greyish discharge with a distinct fishy smell, usually without much itching. It is treated with an antibiotic, not an antifungal, so an antifungal will do nothing for it.
• Trichomoniasis, which is sexually transmitted and needs testing, treatment and partner notification.
• Chlamydia and gonorrhoea, which frequently produce no symptoms at all, which is the argument for testing rather than assuming when there is any possibility of either.
• Contact dermatitis — in effect eczema of the vulva, caused by something applied to it. Perfumed soap, shower gel, bubble bath, wipes, panty liners, intimate deodorants and washes are the usual causes, which is an irony worth sitting with, since several of those products are marketed as the solution to the symptom they are producing.
• Lichen sclerosus, which thins and whitens the skin and makes it fragile and prone to splitting. It needs a proper diagnosis and treatment with a potent steroid ointment, and left untreated over years it carries a small risk of vulval cancer. It is frequently mistaken for recurrent thrush for a long time.
• Genital changes around and after the menopause, where falling oestrogen thins the tissue and produces dryness, soreness and irritation that antifungals will not touch.
• Genital herpes, and vulvodynia, a persistent pain condition with no visible cause.

The practical consequence: a first episode is worth having confirmed rather than guessed at, and symptoms that a full course of treatment has not cleared should always be looked at rather than treated again.

Treatment, which is straightforward

Thrush is treated with an antifungal, available from a pharmacy without a prescription. It comes in three forms, and they work about equally well:

• A pessary or internal cream — clotrimazole is the usual one, with econazole, fenticonazole and miconazole as alternatives. Either a single large dose or a short course over several nights.
• A capsule by mouth — a single dose of fluconazole.
• A cream for the outside, used alongside either of the above for the itching and soreness rather than instead of them.

Most episodes settle within a few days. A severe one may need a second dose a few days after the first. There is no need for any test afterwards if the symptoms have gone.

Three points that get left out:

In pregnancy, when trying to conceive, and while breastfeeding, the oral capsule is avoided. Treatment is topical, and a longer course is used, because short courses cure less reliably in pregnancy.

Antifungal creams and pessaries damage latex. Condoms and diaphragms may fail during treatment and for a few days afterwards.

Thrush treated repeatedly without ever being confirmed is a situation to get out of. At that point either it is not thrush, or it is a Candida species that does not respond to the usual drugs, and both need a swab to establish.

When it keeps coming back

Four or more episodes in a year is defined as recurrent thrush, and affects a small but not trivial proportion of women. It is not something to manage with repeated trips to the pharmacy.

Proper management involves confirming by culture which organism is actually there, then an induction course followed by maintenance treatment over about six months — typically weekly, rather than the single doses used for an isolated episode. There are alternatives for species that resist the standard drugs. Any of this needs a prescription and follow-up.

Recurrence also prompts a look for a reason, and one of those reasons matters a great deal: repeated thrush can be the first sign of undiagnosed diabetes, because glucose in the urine and in the tissues feeds the yeast. Anyone with recurrent episodes, particularly alongside thirst, passing water more often, tiredness or unexplained weight loss, should have this checked — the background is under risk factors for diabetes and in the diabetes section. Where diabetes is already diagnosed, better glucose control reduces the episodes.

Other contributors include courses of antibiotics, hormone replacement therapy, pregnancy, and any condition or treatment that suppresses the immune system.

What actually helps between episodes

Almost all of it is a matter of leaving the area alone rather than doing more to it.

• Stop using soap, shower gel and bubble bath on the vulva, and stop using wipes, intimate washes, deodorants and anything perfumed. An emollient used as a soap substitute does the job without stripping the skin, and is the single most effective change available.
• Wash once a day, not more, with water or an emollient, and only externally.
• Do not wash hair in the bath water, which puts shampoo where it is least wanted.
• Loose clothing and cotton underwear are sensible, and the evidence for them is weaker than their reputation. The same goes for wearing panty liners every day and sitting about in wet swimwear. All worth trying; none a cure.
• Sex does not need avoiding, though it may be uncomfortable where the skin is split. A water-based lubricant helps, and some lubricants are themselves irritant.

Douching, which comes up repeatedly

Douching — flushing the inside of the vagina out with water or anything else — is harmful in itself. It disturbs the resident lactobacilli that maintain the acidity described above, and is associated with infection rather than cleanliness. Every health body advises against it, in all circumstances, including when there are symptoms.

It is worth stating plainly because older writing on natural remedies recommends it frequently, sometimes in the same article that correctly advises against it, and often with something added to the water.

The remedies, assessed honestly

Most of what is recommended for thrush outside medicine has been looked at. The findings, drawn from the British Association for Sexual Health and HIV guideline on the subject:

• Yoghurt, eaten or applied: insufficient evidence of benefit.
• Probiotics and acidophilus supplements: insufficient evidence.
• Honey: insufficient evidence.
• Garlic, taken by mouth: no benefit demonstrated.
• Dietary change — cutting out sugar, yeast or bread: no evidence supports it.

None of those will do harm beyond the delay. One item on the list is different, and it is the reason this article needed rewriting rather than tidying.

Tea tree oil and other essential oils have no useful evidence behind them and are a recognised cause of hypersensitivity reactions. Using one as a suppository, or applying it undiluted to vulval skin, means putting a concentrated plant extract onto mucous membrane — tissue far more absorbent and far more easily damaged than the skin of an arm. The result is chemical irritation and burning on top of whatever the original problem was, and a sensitisation that is permanent once established. Tea tree oil is among the more sensitising of the common oils. The reasoning behind all of this is set out under using essential oils safely, which deals with the general principle: essential oils do not go inside the body.

One substance deserves a note so that nobody improvises it. Boric acid is a genuine second-line treatment, used as a pessary for the Candida species that resist the standard antifungals. It is prepared by a pharmacy on prescription, it is not used in pregnancy, and it is toxic if swallowed. Seeing it named online as a natural remedy and making something up at home is a bad idea.

When to be seen rather than self-treated

• A first episode, where the diagnosis has never been confirmed.
• Pregnancy, or trying to conceive.
• Age under sixteen or over sixty.
• Symptoms still present after a complete course of treatment.
• Four or more episodes in a year.
• Any abnormal bleeding, pain low in the abdomen, fever, or sores and ulcers.
• Any possibility of a sexually transmitted infection, including after a new partner — sexual health clinics test for everything at once and are free to use without a referral.
• White, thinned or fragile vulval skin, or itching that has gone on for months regardless of treatment.

The last of those is the one most often left too long. Persistent vulval itching is a symptom that deserves a diagnosis, not a shelf of antifungals.