Tonsillitis is inflammation of the tonsils, typically of quick onset. It is a type of pharyngitis.Symptoms may include sore throat, fever, expansion of the tonsils, trouble swallowing, and large lymph nodes around the neckTonsillitis is most regularly caused by a viral contagion, with about 5% to 40% of cases caused by a bacterial infection. When triggered by the bacterium group A streptococcus, it is referred to as strep throat. Rarely microorganisms such as Neisseria gonorrhoeae, Corynebacterium diphtheriae, or Haemophilus influenzae may be the cause.Typically the infection is spread among people through the air.A scoring system, such as the Centor score, may help separate possible origins. Confirmation may be by a throat swab or quick strep test.