The same as pharyngitis. However, both tonsils are swollen and red. There may be yellow spots (follicles) or an exudate (yellow mucoid covering) on the tonsils. With very swollen and inflamed tonsils, the airway may become narrow.

The tonsils normally grow and enlarge in young infants as part of the development of their immune system. Normally the size of the tonsils decreases by 10 years of age. Tonsillitis is more common in children with large tonsils. However, many children have enlarged tonsils without repeated attacks of tonsillitis.

Usually tonsillitis recovers within a week. However, tonsillitis may become recurrent or chronic.