Which of the following is a primary function of corticosteroids in allergy treatment?

Corticosteroids play a critical role in allergy treatment primarily through their ability to reduce swelling and inflammation. When an allergic reaction occurs, the body often experiences an inflammatory response characterized by the release of various mediators that can lead to symptoms such as redness, swelling, and itching. Corticosteroids effectively modulate this inflammatory response by suppressing the immune system's exaggerated reaction to allergens.

By decreasing the production of inflammatory substances, corticosteroids help to alleviate these symptoms, making them an important therapeutic option for conditions like asthma, hay fever, and other allergic reactions. This anti-inflammatory effect is a key reason why they are frequently prescribed to manage allergies and their associated symptoms.

Other options, while important in different contexts, do not represent the primary function of corticosteroids in managing allergic responses. For instance, preventing infections and providing pain relief are not direct actions of corticosteroids, and increasing energy levels is not related to the treatment of allergies.