Which is an appropriate management step for a child experiencing an asthma attack?

Using a rescue inhaler immediately is the most appropriate management step for a child experiencing an asthma attack. Rescue inhalers typically contain fast-acting bronchodilators that work to quickly relax the muscles in the airways, allowing for easier breathing. During an asthma attack, the airways become inflamed and constricted, leading to difficulty breathing, wheezing, and coughing. Administering the rescue inhaler promptly can alleviate these symptoms and help restore normal airflow, making it a critical step in emergency management of an asthma attack.

The other options, while they could have relevance in a different context, do not address the immediate need for relief during an asthma attack. Encouraging exercise can exacerbate symptoms during an asthma attack rather than help. Providing a cold drink does not address the underlying airway constriction and may not provide any relief. Allowing symptoms to subside on their own could lead to a worsening condition and delay necessary treatment, which is especially dangerous during an asthma attack when timely intervention is crucial.