Swollen tonsils can accompany a number of different infections of the upper respiratory tract. Some people have larger tonsils than others, and it is possible to have large tonsils without associated symptoms or problems. Tonsillitis refers to inflammation of the tonsils, which typically occurs due to infection. Infection is most commonly due to viruses or bacteria. Tonsillitis is a common illness, especially in children. It is possible to have multiple episodes of tonsillitis throughout life. Tonsillitis is often accompanied by other symptoms, including sore throat, cough, sneezing, enlarged lymph nodes, fever, chills, hoarseness, headache, muscle aches, or fatigue. When the tonsils are infected, they may also appear to be coated with yellowish-white pus.