Pathophysiology
Clinical meaning
Pediatric asthma diagnosis is challenging, particularly in children < 5 years where spirometry is unreliable. In this age group, diagnosis relies on symptom pattern (recurrent wheeze, cough, dyspnea triggered by viral infections, allergens, exercise, or cold air), family history of atopy, and therapeutic response to ICS trial. The modified Asthma Predictive Index (mAPI) helps predict asthma persistence: at least 3 wheezing episodes in past year PLUS one major criterion (parental asthma, atopic dermatitis, aeroallergen sensitization) OR two minor criteria (food allergy, eosinophilia > 4%, wheezing apart from colds). In children >= 6 years, spirometry with bronchodilator reversibility (FEV1 increase >= 12%) confirms diagnosis. Asthma phenotypes in children include viral-triggered wheeze (transient, resolves by school age), multi-trigger wheeze (persistent, atopic), and exercise-induced bronchoconstriction. Treatment follows a step-wise approach adapted for age with ICS as the cornerstone controller.