There are some nasty bugs out there and our mouth is often the first place these bad boys land.
Thrush is an example of one such infections. Thrush is caused by yeast, which are slow growing microorganisms that exist just about everywhere.
Most of the time our immune system wards these invaders off. However, if for some reason either the immune system is on the blink ( ie cancer, chemotherapy, patients on Prednisone and other drugs which slow down the immune system) or if there is something wrong in your mouth such as rotten teeth, then thrush can occur. It also is more common in infants, as their immune system is somewhat immature and therefore not fully functional. If you have just finished or are taking antibiotics, thrush is more common. This is because the antibiotics kill off some of the good mouth microorganisms which help ward off thrush.
Thrush looks like a bad painter had quickly put on some white paint on to the tongue and sides of the mouth. Other more dangerous conditions including precancers and cancers can at times look very similar to this. However, these are much more unusual
Thrush is treated with antifungal agents, which usually are gargled and then swallowed. There are pills as well.
In some patients, especially those with poorly working immune systems, the yeast infection can spread to the esophagus. This often presents with painful swallowing. This is more serious and can even occasionally require iv medications to treat.
If you notice some white plaques over your tongue, then have your doctor examine you to see if thrush is present.