Epiglottitis is the inflammation of the epiglottis—the flap at the base of the tongue that prevents food entering the trachea (windpipe). Symptoms are usually rapid in onset and include trouble swallowing which can result in drooling, changes to the voice, fever, and an increased breathing rate. As the epiglottis is in the upper airway, swelling can interfere with breathing. People may lean forward in an effort to open the airway. As the condition worsens, stridor and bluish skin may occur.
Epiglottitis was historically mostly caused by infection by H. influenzae type b (commonly referred to as "Hib"). Following the introduction of the Hib vaccine, pediatric cases of epiglottitis fell from 3.47 cases per 100,000 children in 1980 to 0.63 cases in 1990 such that it is now more often caused by other bacteria, most commonly Streptococcus pneumoniae, Streptococcus pyogenes, or Staphylococcus aureus. Predisposing factors include burns and trauma to the area. The most accurate way to make the diagnosis is to look directly at the epiglottis. X-rays of the neck from the side may show a "thumbprint sign" but the lack of this sign does not mean the condition is absent.