What are fungal infections? Fungal infections are infections caused by a fungus, a type of microorganism. Two common causes of fungal infections are a fungus called tinea and yeast infections caused by the fungus Candida albicans. Some very common types of fungal infections caused by tinea include: Athlete’s foot Jock itch Ringworm Common yeast infections, also called candida and candidiasis, can infect other areas of the body including: Esophagus Digestive tract (gastroenteritis) Lungs Mouth (oral thrush) Urinary tract Vagina (vaginal yeast infection, vaginal thrush) In most cases, fungal infections are treatable in generally healthy people. However, these infections are more likely to occur and can be more difficult to treat in people with weakened immune systems due to such conditions as HIV/AIDS, diabetes, organ transplantation, or taking steroid medications or chemotherapy. In these cases, complications of fungal infections may become life threatening. Recurring fungal infections can also be a symptom of a serious, undiagnosed, underlying disease, such as HIV/AIDS or diabetes. Seek prompt medical care for recurring fungal infections including vaginal yeast infections.