It usually occurs in children between two and 5 years of age. The onset is sudden with:

• High fever. These children appear very sick and may be shocked due to the septicaemia.
• Drooling. They have a very sore throat and are unable to swallow or even open their mouth. This is a very important sign. They usually are unable to speak, cry, cough or drink.
• They have progressive airway obstruction. Characteristically, the children sit up, leaning forward with the neck extended to keep the airway open.
• Changing their body position or trying to examine the throat may cause total airway obstruction.