Nasal flaring

The widening of the nostrils during inspiration, typically reflecting increased work of breathing and often indicating respiratory distress, especially in infants and young children. Possible causes are respiratory infections (bronchitis, pneumonia, bronchiolitis), asthma, airway obstruction (swelling, inflammation, croup, epiglottitis), ARDS, heart failure, anaphylaxis, chronic lung conditions, or intense exercise.