Thrush, also known as candida or candidosis, is a yeast infection caused by a fungus called Candida albicans which lives in and around the body.

Both men and women can get thrush. In women, thrush causes itching, irritation, discharge, redness, soreness and swelling of the vagina and vulva. In men, it causes itching, irritation, redness, soreness and discharge under the foreskin, or on the tip of the penis.

It is possible for thrush to be passed on through sexual intercourse, although it is quite rare. A man is more likely to get thrush if he has a weak immune system or poor levels of personal hygiene. Men with a foreskin are more likely to get thrush because the warmth and moisture underneath the skin encourages the yeast infection to grow.

Thrush is not a sexually transmitted infection (STD) because many people already have small amounts of the candida fungus in their bodies. However, the fungus does not usually cause any harm because the body's immune system keeps it under control.

However, anything that weakens your immune system, such as an illness like depression, or antibiotic medication, may cause the candida fungus to multiply, increasing the likelihood that you will develop thrush.

If you have thrush, it is best to avoid sex until you have completed a course of treatment and the infection has cleared up.