Parainfluenza, myxoviruses and measles virus are the most frequently encountered viruses . Respiratory syncytial and influenza viruses and adenoviruses are less frequent as well as herpes virus which is usually associated with prolonged laryngitis .
Diagnosis is mainly clinical in presence of characteristic cough and stridor .
Its incidence in children has decreased considerably since the use of anti-Hemophilus influenzae vaccination . In contrast, in adults its incidence is increasing . The clinical picture includes dyspnea, fever, dysphagia with drooling and absence of cough. The sitting position spontaneously adopted by the child is very characteristic but rarely mentioned. In adolescents, epiglottitis can be pauci-symptomatic and less severe.