According to WebMD, there are certain conditions that cause white spots on the tongue. Because this symptom sometimes indicates a potentially serious condition, it is important to seek medical attention when spots are noticed.
WebMD explains that "leukoplakia" causes mouth cells to grow abnormally fast, and white spots form on the mouth and tongue. The condition is often caused by irritation to the tissue or tobacco products. Leukoplakia itself is not dangerous, but sometimes it signals the possibility of cancer.
Oral thrush is a yeast infection, and spots resembling cottage cheese develop on the mouth and tongue, notes WebMD. The infection often appears when antibiotics or inhaled steroids are used. Thrush is also seen in people with poor or undeveloped immune systems.