An infection caused by overgrowth of the fungus ‘Candida albicans’. The fungus exists naturally in the mouth, throat, vagina, digestive tract and folds of the skin including the penis. Normally candida does not cause disease, although it is a sign of lowered immunity and is a common opportunistic infection in untreated advanced HIV disease. Candidiasis develops if something disrupts the balance of fungus in the body and an overgrowth develops, commonly called thrush. Symptoms vary depending on the site affected. Oral candidiasis – oral/mouth thrush – appears as white patches on the tongue, gums, and inner cheeks, which may be painful. Vaginal candidiasis causes a white discharge and itch. It is a common problem for all women but the prevalence is higher in women who are HIV-positive. HIV-positive men do not seem to have a higher prevalence of penile candidiasis, and it is less common in men overall, although it can be passed on through sexual contact. Candida of the oesophagus (throat) is rarely seen if the immune system is functioning well, and is more likely to develop if the CD4 cell count is below 200. Oesophageal (throat) candidiasis can be painful and may lead to difficulty swallowing. Treatment depends on the site affected but candidiasis responds well to antifungal drugs, although it can also be difficult to treat in severe cases and may often reoccur without any apparent predisposing risk factors.