Vaginal thrush: recognising symptoms, treating it properly and preventing recurrences

What vaginal thrush is

Yeasts of the genus Candida are part of the normal vaginal flora in around one in five women without causing symptoms. Vulvovaginal candidiasis is the term for when the yeasts multiply strongly and inflame the mucosa. According to Sobel’s review in the Lancet, three out of four women experience at least one episode, 40 to 45 percent several. In 85 to 90 percent Candida albicans is the pathogen; rarer species such as Candida glabrata cause milder but more stubborn symptoms and respond less well to standard treatments.

Anything that disturbs the balance of the vaginal flora or feeds the yeasts encourages thrush: antibiotics, which reduce the protective lactic acid bacteria, high oestrogen levels in pregnancy and with some hormonal products, poorly controlled diabetes, weakened immunity, cortisone and a hereditary predisposition. Tight synthetic clothing and intimate sprays play a smaller role than often claimed but irritate the skin.

Symptoms and telling it apart from other causes

The leading symptom is itching, often tormenting and worse at night. Added to this are burning, redness and swelling of the labia and vaginal entrance, whitish, crumbly, odourless discharge, pain during sex and burning when urinating as urine passes over inflamed skin.

Not every discharge with itching is thrush. The S2k guideline stresses that self-diagnosis is frequently wrong and that unnecessary antifungal treatment delays the real cause.

Cause	Discharge	Odour	Itching	Typical additional signs
Vaginal thrush	white, crumbly, thick	none	strong	redness, swelling, burning
Bacterial vaginosis	thin, greyish-white, homogeneous	fishy, stronger after sex	mild	pH above 4.5, little inflammation
Trichomonas	yellow-green, frothy	unpleasant	moderate	burning, redness, sexually transmitted
Contact irritation, allergy	little or normal	none	strong	after new products, detergents, panty liners
Lichen sclerosus	little	none	chronic	whitish, thin skin, tears, mostly after menopause
Genital herpes	little	none	burning, pain	blisters, ulcers, fever with first infection

For a first episode, unclear discharge, after unprotected sex with a new partner or if a treatment fails, a swab with microscopy and fungal culture at the gynaecologist is needed. A known, typical episode, on the other hand, can be treated without examination.

Treatment: what works and for how long

Antifungals from the azole group are the standard. Topical clotrimazole as a vaginal tablet or cream for one, three or seven days and a single dose of fluconazole 150 mg are equally effective: over 80 percent of women are symptom-free after treatment. Symptoms usually subside after two to three days; the itching may last a little longer because the skin needs to heal. For severe external itching an additional cream on the labia helps, briefly also combined with a mild cortisone.

Clotrimazole is available at pharmacies without prescription. Fluconazole is prescription-only (section 48 of the Medicinal Products Act) and has interactions, for example with anticoagulants, some statins and medicines that affect the heart; the list of medicines therefore belongs in every consultation. In pregnancy fluconazole is avoided: a Danish registry study of over 1.4 million pregnancies found an increased risk of miscarriage after use. Topical products for seven days are the choice there.

Yoghurt or tea tree oil in the vagina are not sensible; they irritate and do not help. Lactic acid or lactobacillus products can support the flora after treatment but, on current evidence, only prevent recurrences to a limited extent.

When the video consultation fits and when it does not

The video consultation is well suited if you know thrush, the symptoms are typical and you need a prescription-only treatment or an assessment. The doctor asks about symptoms, duration, pregnancy, contraception, pre-existing conditions such as diabetes, current medicines and frequency of infections and decides on treatment and private prescription.

An examination with a swab is needed for a first episode, for discharge with odour or unusual colour, for fever or lower abdominal pain, for blisters or ulcers, in pregnancy, if a correctly carried out treatment brings no improvement and for four or more infections a year, because then a fungal culture should determine the species.

Recurrent thrush

Four or more episodes per year count as recurrent vulvovaginal candidiasis. Denning and colleagues estimate in the Lancet Infectious Diseases that around 138 million women worldwide are affected each year. The cause is usually not poor hygiene but a combination of predisposition, hormonal status and disturbances of the flora.

The guideline recommends a two-step approach. First the acute episode is treated and the pathogen identified by culture. Then follows maintenance therapy: fluconazole 150 mg once a week for six months. In the study by Sobel and colleagues in the New England Journal of Medicine around 90 percent of women remained symptom-free during therapy; after stopping, however, about half had infections again within a year. Triggers are therefore addressed in parallel: optimise blood sugar, antibiotics only when clearly indicated, review oestrogen-containing products, alternative substances such as boric acid pessaries or nystatin for Candida glabrata.

What helps in everyday life, without promising miracles: wash externally only with water or mild soap, no intimate sprays, change panty liners and tampons regularly, take off wet swimwear, prefer cotton underwear, be alert after a course of antibiotics.

Thrush after antibiotics and in particular phases of life

Antibiotics are the most common avoidable trigger. They kill not only the pathogens of a bladder or throat infection but also the lactic acid bacteria that maintain the acidic vaginal environment. Within a few days yeasts can multiply. Anyone who recognises this pattern can discuss with their doctor planning a preventive single dose of fluconazole or a topical treatment at the start of an antibiotic course. For everyone else: antibiotics only when really necessary, and watch for early signs in the days afterwards.

The cycle also plays a role. Many women notice symptoms in the second half of the cycle, when progesterone is high, or just before their period. Hormonal contraception with a high oestrogen content, pregnancy and hormone replacement therapy also favour yeast growth. After menopause thrush is rarer; itching and burning are then more often due to oestrogen deficiency and dry mucosa, which respond to local oestrogen, not to antifungals.

Poorly controlled diabetes raises the sugar content of the mucous membranes and is one of the first questions with recurrent infections. Anyone with repeated thrush for no apparent reason should have fasting glucose or HbA1c checked; sometimes thrush is the first sign of previously unknown diabetes. Medicines from the SGLT2 inhibitor group used for diabetes and heart failure also raise the risk because they excrete sugar via the urine.

Thrush and your partner, thrush and sex

Thrush is not a sexually transmitted disease. Transmission during sex is possible but plays a minor role in recurrences. Men occasionally develop redness with itching of the glans, treated with an antifungal cream. The guideline advises against routine partner treatment; whoever has symptoms is treated. During treatment you should abstain from sex because the mucosa is irritated and creams can weaken condoms.

If it was not thrush

If itching and burning persist despite treatment, it is worth looking at other causes: bacterial vaginosis, treated with metronidazole or clindamycin, a contact allergy to care products or detergents, lichen sclerosus, which needs long-term cortisone treatment, skin changes from oestrogen deficiency after menopause that respond to local oestrogen, or a sexually transmitted infection. Chronic itching without findings can also be nerve-related. In all cases an examination gets you there faster than the next trial treatment on suspicion.