Which condition is characterized by a sudden onset of respiratory distress and wheezing in children?

The condition characterized by a sudden onset of respiratory distress and wheezing in children is indeed asthma attack. Asthma is a chronic inflammatory disease of the airways that can lead to episodes of difficulty breathing. These episodes, or asthma attacks, are often triggered by exposure to allergens, respiratory infections, or irritants, and they present with symptoms such as wheezing, shortness of breath, chest tightness, and coughing.

During an asthma attack, the airways become significantly narrowed due to bronchoconstriction, increased mucus production, and airway inflammation, leading to the sudden respiratory distress observed in affected children. This condition is particularly notable for the wheezing sound produced when the child exhales, a hallmark sign that differentiates it from other respiratory conditions.

Other conditions like acute bronchitis, pneumonia, and bronchiolitis may also cause respiratory distress, but they typically present with different features and may not have the same immediate and pronounced wheezing associated with asthma. For instance, pneumonia often involves a productive cough with fever and may have crackles rather than wheezing, while bronchiolitis usually presents with respiratory distress due to viral infections in infants and is characterized by a wheezing sound, but it's typically preceded by upper respiratory symptoms.