Causes of stridor
infections – croup, epiglottitis, tracheitis; retropharyngeal or other deep neck space infection
anaphylaxis / angioedema
laryngeal or tracheal trauma
vocal cord paralysis
lesions of the vocal cords – benign or malignant
In very young children:
Be extremely cautious when diagnosing croup in children under 6 months or over 4 years, as it is extremely uncommon at these ages.