Age of Croup
Croup typically affects children between 6 months and 6 years of age, with peak incidence occurring in children 6 months to 3 years of age. 1, 2, 3
Typical Age Range
- The most common age range is 6 months to 6 years, with this representing the classic demographic for viral croup 1, 2, 4
- Peak incidence occurs in children 6 months to 3 years of age, accounting for approximately 3% of children in this age group annually 3
- Children younger than 6 months rarely develop croup, as the airway anatomy and immune exposure patterns differ in this age group 1, 4
- Children older than 6 years can still develop croup, but it becomes progressively less common as the airway diameter increases with age 1, 5
Clinical Context
- Croup accounts for 7% of hospitalizations annually for fever and/or acute respiratory illness in children younger than 5 years 3
- The disease is most commonly seen during late fall and early winter months 1
- Parainfluenza virus is the most common causative agent, though respiratory syncytial virus (RSV) also frequently causes croup 5
Important Caveats
- When a child outside the typical age range (particularly older than 6 years) presents with stridor and barking cough, consider alternative diagnoses including bacterial tracheitis, foreign body aspiration, or retropharyngeal abscess 1, 3
- Influenza can cause a more severe clinical course of croup compared to parainfluenza virus, and may be more likely to result in bacterial tracheitis as a complication 6
- The narrow pediatric airway in the typical croup age range (6 months to 6 years) makes even modest mucosal swelling clinically significant, explaining why the disease predominantly affects this age group 1, 2