Bronchiolitis most often occurs in which age group?

• A. 5-10 years
• B. Adults
• C. Elderly
• D. <24 months

Answer: (D)

Bronchiolitis is an infection that inflames the small airways (bronchioles) and it predominantly affects very young children. The airways in infants and toddlers are narrow, and inflammation with mucus can quickly narrow them, leading to wheezing and fast, shallow breathing. RSV is a common cause, and the incidence is highest in the first two years of life, especially under 12 months. As children get older and their airways grow larger, bronchiolitis becomes less common, and older kids and adults are more likely to have bronchitis or other viral colds rather than classic bronchiolitis. So the age group most affected is children younger than 24 months.