A yeast infection is a common fungal infection, usually caused by Candida, that leads to itching, soreness and discharge. In the vagina it is also known as vaginal thrush.
Typical symptoms include itching and soreness around the vagina, a white discharge that may look like cottage cheese and usually does not smell, and stinging or pain when urinating or during sex. The skin around the vulva can look red or swollen.
Candida yeast normally lives on the skin and in the vagina without causing problems. An infection develops when it grows more than usual. Things that make this more likely include antibiotics, pregnancy, diabetes that is not well controlled, a weakened immune system and hormonal changes. Thrush is not a sexually transmitted infection, although sex can sometimes trigger it.
Antifungal medicines, as creams, pessaries or tablets, are the usual treatment, and some are available from a pharmacist. See a GP or doctor if it is your first yeast infection, if you are pregnant, if symptoms do not improve after treatment, or if infections keep coming back.
Yeast infections share some symptoms with other conditions, such as bacterial vaginosis (BV) and sexually transmitted infections. BV often causes a thin, grey-white discharge with a fishy smell, and it is usually less itchy. Because the treatments differ, a doctor, nurse or pharmacist can help confirm the cause before treatment. Recurring infections may be checked with a swab test.
Sources: NHS, MedlinePlus.