Some common diseases that affect the tongue include leukoplakia, Kawasaki syndrome and oral thrush, according to MedicineNet. Leukoplakia and oral thrush can cause a white tongue, while Kawasaki syndrome can cause a red tongue.
Leukoplakia is a condition where thick, white patches form inside the mouth that are impossible to remove, explains Mayo Clinic. Experts believe tobacco is the main cause for the condition, and symptoms are usually localized to where a person holds tobacco in his mouth. While leukoplakia usually is not serious, it can lead to oral cancer.
Kawasaki syndrome is a disease that causes inflammation in the walls of medium-sized arteries, notes Mayo Clinic. The disease also affects lymph nodes, mucous membranes and the skin. People with Kawasaki syndrome experience different symptoms for each of the three phases of the disease. Symptoms can include fever, rash, diarrhea and abdominal pain. Treatment for Kawasaki syndrome, such as gamma globulin infusions, reduces complications, since the disease usually goes away after 12 days.
Oral thrush is a yeast infection of the mouth due to an overgrowth of the candida fungus, according to WebMD. Certain factors that can cause candida overgrowth include the use of medications, such as antibiotics, and having diseases, such as uncontrolled diabetes, HIV and cancer. Symptoms of oral thrush include white lesions in the mouth, difficulty swallowing and fever. Antifungal medication treats the condition, and good oral hygiene practices prevent it.