Thrush (candidiasis)

Overview

Thrush is an infection caused by Candida, which lives on the skin and in places such as the mouth, throat and vagina, usually without causing symptoms. It can cause problems in the genital area of women and men, in the mouth, and on areas of skin such as the armpits and groin. The NHS says it is not classed as a sexually transmitted infection, although it can be triggered by sex or, less often, passed on during sex. It is usually treated with antifungal medicine.

Symptoms

What a clinician may find

• A white, often odourless discharge with itching and irritation around the vagina and vulva
• Redness and irritation around the head of the penis and under the foreskin, sometimes with a white discharge
• Red areas with white patches in the mouth of an adult with oral thrush
• A white coating on the tongue in babies
• A red, itchy rash in skin folds such as the armpits, groin and under the breasts

Complications

• Thrush that keeps coming back, which may need longer treatment
• Painful or difficult swallowing when the throat or oesophagus is involved
• Passing thrush back and forth between a breastfeeding mother and her baby
• Invasive candidiasis, which can involve the bloodstream and is a separate condition; the CDC says most people are not at risk of it

Diagnosis

UK sexual health guidance (BASHH) says the diagnosis of candidiasis rests on symptoms and clinical findings together, not on culture results alone. If it is unclear, the area may be examined and a cotton bud used on the discharge to test for other infections. If thrush keeps coming back, a vaginal swab may be taken to check whether a different kind of yeast is the cause. For men, a GP will want to confirm that it is thrush and rule out other infections. The BASHH guideline on recurrent vulvovaginal thrush expects diagnosis to be confirmed by microscopy or culture when symptoms are present.

Treatment

Thrush is usually treated with antifungal medicine, given as a tablet, a pessary placed in the vagina, or a cream. The NHS says thrush in men and women should clear up within 7 to 14 days of starting treatment. Partners generally do not need treatment unless they have symptoms. Treatment may be given for longer if thrush keeps coming back. For oral thrush, a pharmacist can supply an antifungal mouth gel. When a breastfeeding mother and her baby have thrush, both are treated at the same time. For skin thrush, MedlinePlus says antifungal skin creams, ointments or powders may be used.

Prevention

The NHS suggests washing the genital area with water or an emollient instead of soap, drying thoroughly, wearing cotton underwear, and avoiding douching. For oral thrush, the NHS lists good dental care, rinsing the mouth after using inhalers, not wearing dentures at night and not smoking.

Key facts

What is thrush?

Thrush is an infection caused by Candida, a fungus that is normally harmless. The CDC says Candida is normally present on the body and that most of the time it causes no symptoms. The CDC lists several types of candidiasis, including vaginal yeast infections, oral thrush and skin infections. The NHS says thrush can affect the genital area in both men and women, and can also appear on other areas of skin such as the armpits, groin and between the fingers.

Oral thrush, also called mouth thrush, is described by the NHS as usually harmless and common in babies and in older people with dentures. Oral thrush in adults is not contagious, according to the NHS. Thrush is not classed as a sexually transmitted infection, but it can be triggered by sex or, less often, passed on during sex.

What are the symptoms of thrush?

In women, the NHS lists a white discharge that is often odourless and may look like cottage cheese, with itching and irritation around the vagina and vulva. Stinging during sex or when passing urine can also occur. In men, symptoms can include irritation, burning and redness around the head of the penis and under the foreskin, a white discharge, an unpleasant smell, and difficulty pulling back the foreskin.

In oral thrush, adults may have a red mouth with white patches, while babies may have a white coating on the tongue. The CDC adds that infection of the oesophagus can cause pain and difficulty swallowing. On the skin, MedlinePlus describes intense itching with rashes in skin folds, the genitals and under the breasts. The CDC describes skin infection as an itching or burning rash with skin breakdown.

What causes thrush and who is more likely to get it?

Candida is normally harmless, and in the vagina normal bacteria usually keep its growth under control. The NHS lists several things that raise the risk, including antibiotics, poorly controlled diabetes, a weakened immune system, hormone replacement therapy and pregnancy. Irritated or damaged skin is also mentioned. The CDC says pregnancy and hormone changes raise the risk of vaginal candidiasis.

For oral thrush, NHS inform lists recent antibiotics, inhaled steroids such as some asthma inhalers, dentures, poor oral hygiene and dry mouth. The CDC says babies under one month old and people with HIV/AIDS have a higher risk of candidiasis in the mouth, throat or oesophagus. Diabetes UK says high sugar in the urine raises the risk of thrush, which is one reason diabetes is linked with it. NHS inform says that, for oral thrush, a GP may sometimes recommend blood tests to check for conditions such as diabetes.

How is thrush diagnosed and treated?

UK sexual health guidance (BASHH) says the diagnosis of candidiasis rests on symptoms and clinical findings together, not on culture results alone. If it is unclear, the area may be examined and a cotton bud used on the discharge to test for other infections. If thrush keeps coming back, a vaginal swab may be taken to check whether a different kind of yeast is the cause. For men, the NHS says a GP will want to confirm that it is thrush and rule out other infections. The BASHH guideline on recurrent vulvovaginal thrush expects diagnosis to be confirmed by microscopy or culture when symptoms are present.

Treatment is usually an antifungal medicine, given as a tablet, a pessary placed in the vagina, or a cream to ease irritation. The NHS says thrush in men and women should clear up within 7 to 14 days of starting treatment, and that partners generally do not need treatment unless they have symptoms. If thrush keeps coming back, treatment may be given for longer. For oral thrush, a pharmacist can supply an antifungal mouth gel.

Thrush in pregnancy, babies and breastfeeding

The CDC says pregnancy and hormone changes raise the risk of vaginal candidiasis, and the NHS says there is no evidence that thrush can harm an unborn baby. The NHS advises pregnant women to check with a GP or midwife before using any thrush treatment. The NHS advises against anti-thrush tablets in pregnancy, when trying to conceive or while breastfeeding, and describes a cream or pessary as the alternative. A baby can also catch thrush during delivery if the mother has it.

About 1 in 7 babies develops oral thrush at some point, according to a Kingston and Richmond NHS Foundation Trust leaflet. White patches on a baby's tongue that do not rub off easily can point to thrush, whereas a milk coating usually rubs off. If a breastfeeding mother or her baby has thrush, both are treated at the same time because it can easily spread between them. Breastfeeding can continue during treatment.

How can thrush be prevented, and when should medical help be sought?

The NHS suggests washing the genital area with water or an emollient instead of soap, drying thoroughly, wearing cotton underwear, and avoiding douching. For oral thrush, it lists good dental care, rinsing the mouth after using inhalers, not wearing dentures at night and not smoking.

A GP appointment, or a sexual health clinic, is the route the NHS suggests for a first episode, treatment that has not worked or thrush that keeps returning. Pregnancy, breastfeeding and a weakened immune system are also reasons to get advice, and a pharmacist can advise on treatment. For oral thrush, non-urgent GP advice is suggested if there is no improvement after a week of mouth gel, if swallowing is difficult or painful, or if a baby under 4 months has signs of thrush. The CDC separately describes invasive candidiasis, which can involve the bloodstream, and says most people are not at risk of it.

Frequently asked questions