What Are the Causes of Thrush Mouth?


Everyone has a number of unhealthy and healthy organisms in their mouth. Normally the healthy ones will keep the unhealthy ones at levels that do not cause illness. One of these unhealthy microorganisms is called candida fungus, which is also found in the digestive tracts and skin.

Sometimes certain medicines, stress or illnesses can destroy this balance between healthy and unhealthy organisms, challenge the immune system and make us less resistant to infection. The candida fungus will grow beyond normal limits and cause mouth and tongue lesions, also known as thrush mouth.


Many medications have side effects and we have to take the good with the bad. There are a number of pharmaceuticals that will increase the unhealthy organisms in our mouths. These include antibiotics, prednisone, birth control pills and corticosteroids. People who are having chemotherapy treatments for cancer are also at risk for thrush mouth.

Illnesses and Health Conditions

Candida will also increase when the immune system is suffering with illness. The virus that causes AIDS also greatly injures the immune system, which makes thrush mouth very common in later stages of the disease. Those who have HIV may also be at risk. Cancer victims have a greater chance of having thrush mouth with their weakened immune system. If people do not know they have diabetes or are not treating the illness well enough, their "surgary" saliva will increase candida fungus growth. Pregnant women may get thrush mouth due to a hormonal changes.

Mothers and Babies

Many pregnant women get thrush mouth or vaginal infections, which are both caused by candida fungus. This condition can be passed to the baby during delivery, and the newborn may get thrush mouth a couple of weeks later. Some babies are also susceptible, because their immune system is not strong enough to fight off the candida. In some cases, the mothers and infants pass the thrush mouth to each other through breastfeeding. However, some mothers do not get infected when breastfeeding their babies who have this condition, and some babies do not get thrush mouth from their mothers who have a yeast infection.

Seniors and Elderly

Seniors who wear dentures are at greater risk of thrush mouth, so it is important to clean the mouth and the dentures very well every evening. The condition is also called denture sore mouth or "stomatitis." Soft liners in dentures may increase the risk. The elderly often get thrush mouth because their immune system is also weakened or they have a physical ailment or injury or another illness. The condition becomes more difficult to eliminate and has a greater opportunity to spread in those who are ailing. Elderly individuals should be checked regularly.

Miscellaneous Causes

People who smoke cigarettes and cigars are more at risk of thrush mouth, as are those who have dry mouth syndrome and do not produce enough saliva. Other immune deficiency illnesses, such as mononucleosis, thyroid disorders and Sjogren's syndrome, may also cause an increase in yeast and thrust mouth. Similarly, when people are run down and very tired or highly stressed, it is more possible to have the condition.