A yeast infection in the mouth, also referred to as oral thrush, causes thick, white patches to grow inside the mouth. Treatments such as proper oral hygiene and anti-fungal medications help remedy the infection. The infection occurs when an imbalance causes the naturally occurring fungus, called Candida albicans, to accumulate in the mouth, according to the University of Maryland Medical Center. Certain medical conditions increase the risk of causing a disruption in the delicate balance.
Diabetes
Individuals with diabetes have an increased risk of developing an oral yeast infection, especially uncontrolled diabetes. High blood sugar levels in the mouth and excreted in saliva can feed the Candida fungus and allow it to thrive.
Suppressed or Weakened Immune System
Individuals with suppressed or weakened immune systems can develop an oral yeast infection. Viruses such as HIV or AIDS destroy the immune system and allow infections to occur easily in the body, including an overgrowth of yeast. People undergoing treatments for cancer such as chemotherapy or radiation have a weakened immune system. With the body's defenses weak, the risk of developing thrush increases. Another major group of individuals with a suppressed immune system that can experience bouts of thrush includes people on anti-rejection medications following an organ transplant.
Medications
Certain medications can cause thrush to occur. Corticosteroids, antibiotics and birth control pills can all upset the balance of microorganisms in the mouth and cause the overgrowth of fungus. Antibiotics can kill off good bacteria along with the bad and allow the fungus to spread because of the disturbed balance. Birth control pills alter hormone levels, which puts a woman at risk for fungal overgrowth.
Pregnancy, Childbirth and Breastfeeding
Due to altered hormone levels, pregnant women have an increased risk of developing yeast infections. A vaginal yeast infection can pass from the mother to the baby during birth and cause an oral infection for the newborn, according to MayoClinic.com. Due to the immature immune system in a newborn, they are at a greater risk for developing thrush and can pass the yeast back to the mother during breastfeeding. To break the cycle of passing the yeast between mother and child, both may require anti-fungal treatment.
Dry Mouth and Irritation
Individuals who have a dry mouth from conditions such as mouth breathing, smoking or who experience chronic irritation in the mouth from conditions such as poor fitting dentures can develop thrush.
