Also known as laryngotracheobronchitis
Typically affects ages 6 mo-3 yr (peak in 2nd year)
May affect older children
Most common in fall & winter
May affect older children
Most common in fall & winter
Parainfluenza (50% - 75%)
Influenza A and B (usually more severe clinical picture)
RSV
Rhinovirus
Consider Diphtheria if not immunized
Spasmodic<unk> 
Sudden onset of barking cough/stridor
No viral prodrome, unlike typical<unk> 
Difficult to differentiate from typical<unk> 
Must rule out foreign body
Rhinovirus
Consider Diphtheria if not immunized
Sudden onset of barking cough/stridor
No viral prodrome, unlike typical<unk> 
Difficult to differentiate from typical<unk>
Croup
Laryngotracheomalacia
Laryngitis
Accounts for 60%
Sinusitis
Usually exacerbated by viral URI
Epiglottitis
Dx w/ flexible fiberoptic laryngoscopy