White spots under the tongue and a white coating on top of the tongue can be signs of oral thrush, leukoplakia or oral lichen planus among other problems, according to WebMD. If a person finds that they have white spots under their tongue, the person should schedule an appointment with a doctor to have an examination and possible tests performed.
Oral thrush is a condition with white spots that look as though they have been formed in a "cottage cheese-like" shape and consistency. It is seen in people with immune systems that are not strong, such as the elderly or a person with lung disease. It is an infection that is not serious and can be cured with medications and by adding "good bacteria" to the mouth, says WebMD.
Leukoplakia is a condition where white spots under the tongue and all around the mouth are present, states WebMD. Then mouth cells start to grow and grow at a much faster rate than is expected. This problem is not necessarily cancerous, but can easily become cancerous. Oral lichen planus looks like white lines rather than white spots. These white lines are also slightly elevated on the tongue. To get rid of oral lichen planus, it is important to learn good dental hygiene and to stay away from irritating foods and tobacco.