On physical examination, the child appears toxic and apprehensive and frequently assumes an airway-preserving posture, i.e. sitting upright, with the jaw protruding forward, while drooling. Respiration is deliberate without marked tachypnoea. Tachycardia out of proportion to the amount of pyrexia is a reflection of the hypoxia. Should stridor be absent, an unwary physician might underestimate the severity and rapidity of progression of the patient's worsening air exchange, which may result in cardiopulmonary arrest if left untreated. The presentation of acute epiglottitis in adults is more variable.
Most adults have mild illness with a prolonged prodrome.
Some patients may be treated for presumed pharyngitis. In a report of five patients with AIDS, the clinical presentation was notable for a paucity of physical findings. Laryngoscopy revealed a large, pale, boggy epiglottis with an oedematous supraglottis, and cervical adenopathy coupled with rapidly progressing airway obstruction. No attempt should be made to visualize the epiglottis in an awake young child, and therefore a severely ill child must be examined in the operating room at the time of control of the airway. In adults, however, awake indirect laryngoscopy is usually sufficient to make the diagnosis.