Severe intermittent wheezing in preschool children: A distinct phenotype

Background: Young children with wheezing predominantly with respiratory tract illnesses experience severe exacerbations separated by extended periods of wellness and may be described as having "severe intermittent wheezing," a diagnostic category not currently recognized in national guidelines. Objective: We sought to characterize a cohort of children with recurrent severe wheezing. Methods: A total of 238 children 12 to 59 months enrolled in the Acute Intervention Management Strategies trial were characterized through comprehensive allergy, asthma, environmental, and quality of life assessments. Results: Asthma symptoms over the period of the preceding year occurred at frequencies consistent with intermittent asthma, as 94.5% of children experienced activity limitation : 2 times per month. However, frequent severe exacerbations were common, because 71% experienced >= 4 wheezing episodes over the period of the preceding year, 95% made at least I primary care visit, 52% missed school or daycare, 40% made an emergency department visit, and 8% were hospitalized for wheezing illnesses. Atopic features were common, including eczema (37%), aeroallergen sensitization (46.8%), and positive asthma predictive index (59.7%). Oral corticosteroid use in the previous year (59.7% of the cohort) identified a subgroup with more severe disease documented by a higher incidence of urgent care visits (P =.0048), hospitalizations (P = .0061), aeroallergen sensitization (P = .007), and positive asthma predictive indices (P = .007). Conclusion: Among preschool children enrolled in the Acute Intervention Management Strategies trial, a subgroup was identified with severe intermittent wheezing characterized by atopic features and substantial illness-related symptom burden despite prolonged periods of wellness. Clinical implications: Preschool children with recurrent severe wheezing episodes experience significant illness-related morbidity and exhibit features of atopic predisposition.