**Core Concept**
Asthma is a chronic inflammatory disease of the airways characterized by recurring episodes of wheezing, coughing, chest tightness, and shortness of breath. The management of asthma in children involves controlling inflammation, preventing symptoms, and improving quality of life.

**Why the Correct Answer is Right**
In children under 5 years, the most effective and commonly recommended treatment for asthma is a combination of inhaled corticosteroids (ICS) and bronchodilators. ICS reduce inflammation in the airways, while bronchodilators help to relax the muscles around the airways, making it easier to breathe. The combination of ICS and bronchodilators is often administered via a nebulizer or metered-dose inhaler (MDI) with a spacer to ensure accurate and efficient delivery of the medication.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because inhaled corticosteroids are the cornerstone of asthma management in children, and bronchodilators are only used as needed for acute symptom relief.
* **Option B:** This option is incorrect because systemic corticosteroids are not typically used as a first-line treatment for asthma in children due to potential side effects.
* **Option C:** This option is incorrect because while bronchodilators are used to relieve acute symptoms, they do not address the underlying inflammation and are not a substitute for ICS.

**Clinical Pearl / High-Yield Fact**
Children under 5 years with asthma often require a combination of inhaled corticosteroids and bronchodilators to control symptoms and prevent exacerbations. The use of a spacer with a metered-dose inhaler is crucial to ensure accurate and efficient delivery of medication.

**Correct Answer: A. Inhaled corticosteroids and bronchodilators.**