Epiglottitis is a potentially life-threatening condition that occurs when the epiglottis — a small cartilage "lid" that covers your windpipe — swells, blocking the flow of air into your lungs. A number of factors can cause the epiglottis to swell — burns from hot liquids, direct injury to your throat and various infections. The most common cause of epiglottitis in children in the past was infection with Haemophilus influenzae type b (Hib), the same bacterium that causes pneumonia, meningitis and infections in the bloodstream. Epiglottitis can occur at any age.