Which of the following is a characteristic feature of asthma in children?

The characteristic feature of asthma in children includes the improvement of symptoms with bronchodilators, making this the correct choice. Asthma is a chronic inflammatory disease of the airways that results in symptoms such as wheezing, coughing, shortness of breath, and chest tightness. One of the hallmark characteristics of asthma is the reversible nature of airway obstruction, which can be alleviated by the use of bronchodilators. These medications work by relaxing the muscles around the airways, leading to improved airflow and reduced symptoms.

In contrast, the other options do not align with the typical presentation of asthma. A consistent cough without variation may not indicate the episodic nature of asthma symptoms. A cough associated with a high fever suggests an infectious process rather than an asthma exacerbation, as asthma is generally not characterized by fever. Lastly, respiratory symptoms that only occur during exercise may be indicative of exercise-induced bronchoconstriction, but this does not encompass the overall characteristic features of asthma, which can also present with various symptoms at rest or in response to triggers unrelated to physical activity.