Historical data	Possible etiology
Age of onset
Birth	Vocal cord paralysis, congenital lesions such as choanal atresia, laryngeal web and vascular ring
4 to 6 weeks	Laryngomalacia
1 to 4 years	Croup, epiglottitis, foreign body aspiration
Chronicity
Acute onset	Foreign body aspiration, infections such as croup and epiglottitis
Long duration	Structural lesion such as laryngomalacia, laryngeal web or larynogotracheal stenosis
Precipitating factors
Worsening with straining or crying	Laryngomalacia, subglottic hemangioma
Worsening in a supine position	Laryngomalacia, tracheomalacia, macroglossia, micrognathia
Worsening at night	Viral or spasmodic croup
Worsening with feeding	Tracheoesophageal fistula, tracheomalacia, neurologic disorder, vascular compression
Antecedent upper respiratory tract infection	Croup, bacterial tracheitis
Choking	Foreign body aspiration, tracheoesophageal fistula
Associated symptoms
Barking cough	Croup
Brassy cough	Tracheal lesion
Drooling	Epiglottitis, foreign body in esophagus, retropharyngeal or peritonsillar abscess
Weak cry	Laryngeal anomaly or neuromuscular disorder
Muffled cry	Supraglottic lesion
Hoarseness	Croup, vocal cord paralysis
Snoring	Adenoidal or tonsillar hypertrophy
Dysphagia	Supraglottic lesion
Past health
Endotracheal intubation	Vocal cord paralysis, laryngotracheal stenosis
Birth trauma, perinatal asphyxia, cardiac problem	Vocal cord paralysis
Atopy	Angioneurotic edema, spasmodic croup
Family history
Down syndrome	Down syndrome
Hypothyroidism	Hypothyroidism
Psychosocial history
Psychosocial stress	Psychogenic stridor