For a patient experiencing a severe allergic reaction, what is the second-line treatment after epinephrine?

In the management of a severe allergic reaction, also known as anaphylaxis, epinephrine is the first-line treatment due to its rapid action in counteracting airway swelling, vasodilation, and bronchospasm. Once epinephrine has been administered, the second-line treatment typically involves antihistamines, such as diphenhydramine.

Antihistamines work by blocking the action of histamine, a substance released during an allergic reaction that contributes to symptoms like itching, hives, and some gastrointestinal disturbances. While epinephrine addresses life-threatening symptoms, antihistamines can help alleviate less severe symptoms that may persist after the initial management with epinephrine.

Corticosteroids, on the other hand, can be helpful in reducing inflammation and managing delayed symptoms, but their onset of action is not immediate and they are not considered a second-line treatment in acute situations. Beta-agonists are primarily used for bronchospasm in other conditions like asthma rather than for treating allergic reactions directly. Intravenous fluids might be needed in cases of shock but are not considered a specific secondary treatment for allergic reactions.

Thus, antihistamines serve a critical role in continuing the management of symptoms after the initial treatment with epinephrine, making