Thrush is caused by a group of yeast (fungi) called Candida. It is the same organism responsible for thrush in newborns and yeast infections in women. The organism is normally found present in the mouth of all individuals but does not cause disease if the immune system works normally. According to the Mayo Clinic, when the immune system is compromised, this opportunistic organism takes over and causes disease symptoms.
Cancer and Surgical Procedures
Cancer has been known to suppress the immune system by causing complications such as pneumonia---inflammation of the lung and septicemia---infection of the blood. The immune system works overtime to combat these infections thereby becoming suppressed. Cancer treatments such as chemotherapy and radiation destroy normal cells along with cancer cells which puts a lot of stress on the body and its immune system.
Organ and bone marrow transplant predisposes individuals to thrush because of immune suppression drugs. The drugs are given to patients to prevent organ rejection. When organs are transplanted, the body's immune system views the transplanted organ as an invader and tries to destroy it. Drugs help to prevent this occurrence.
Open heart surgery and artificial heart valves also predispose individuals to Candida infection. The organism is able to gain entry into the body when the skin barrier is opened. It is for this reason surgery is a last resort because it can lead to infections.
Diabetes and HIV
Diabetes is a disease where the body is unable to produce enough insulin to absorb glucose from the blood. The glucose remains in the blood and body fluids like saliva. High glucose in saliva enables the Candida organism to grow causing thrush.
HIV, the virus causing AIDS kills-off important T-Cells of the immune system which are responsible for identifying invaders and setting them up to be destroyed. As T-Cells die off, Candida grows unchecked by the immune system.
Antibiotics
Antibiotics have been used for decades to treat bacterial infections. The problem arises when good bacteria, which are part of the normal flora of the body, are destroyed along with the disease causing ones. This gives organisms like Candida an opportunity to grow because the competition has been removed.
Vaginal Yeast Infections
Yeast infections caused by Candida are very common in women and become a problem when pregnant. Although the organism is not dangerous, it can pass on to the child during delivery.
