Croup is primarily a disease of early childhood, with the majority of cases occurring in children between the ages of 6 months and 3 years. It is estimated that around 3% of children develop croup each year, and the condition is more common in boys than in girls, with a male-to-female ratio of approximately 1.5:1. The incidence of croup tends to peak during the fall and early winter months, corresponding to the seasonal prevalence of the viruses that commonly cause the illness, particularly the parainfluenza virus. However, cases of croup can occur throughout the year.
While croup is generally a mild illness, severe cases do occur, and the condition can be life-threatening if the airway obstruction becomes significant. In the United States, croup accounts for approximately 7% of hospitalizations for fever or acute respiratory illness in children under the age of five. However, more than 85% of cases are considered mild and can be managed at home or with outpatient treatment. Fewer than 5% of children with croup are admitted; severe cases, which occur in less than 1% of patients, may require hospitalization for closer monitoring and more intensive treatment, and only 1 to 3% of admitted children need intubation. Mortality from croup is rare, but it can occur in extreme cases, particularly if complications such as bacterial tracheitis or pneumonia develop.
