A 5-year-old presents with nausea, vomiting, abdominal cramping, and hives after eating. What is the priority intervention?

Administering intramuscular epinephrine is the priority intervention in this scenario due to the potential for anaphylaxis, which is a severe and life-threatening allergic reaction. The symptoms presented—nausea, vomiting, abdominal cramping, and hives—indicate the possibility of an allergic reaction, especially since they occurred following food ingestion.

Epinephrine works quickly to reverse the symptoms of anaphylaxis by constricting blood vessels, thereby raising blood pressure, relaxing airways to ease breathing, and reducing swelling. These actions are critical in preventing progression to more severe symptoms, such as respiratory distress or shock. The immediate administration of epinephrine can be lifesaving, making it the top priority in the context of suspected anaphylaxis.

While other interventions like oral hydration and antihistamines may play roles in managing allergies or mild reactions, they do not address the potential acute danger posed by anaphylaxis as effectively or urgently as epinephrine does. In cases of serious allergic reactions where respiratory or circulatory complications may develop, timely treatment with epinephrine is essential to prevent deterioration of the child's condition. Observational protocols are appropriate for monitoring but may not provide the rapid response needed in such a critical situation.