A 5-year-old has a bee sting with delayed vomiting and diarrhea two hours later, with hives but no airway symptoms. Which intervention is FIRST for suspected anaphylaxis?

• A. Administration of epinephrine 0.01 mg/kg 1:1000 IM
• B. Administration of diphenhydramine 25-50 mg PO
• C. Dexethasone 1 mg/kg IV
• D. Diphenhydramine 25-50 mg IV

Answer: (A)

Anaphylaxis is a rapidly evolving emergency, and the most important step is to give epinephrine right away. Epinephrine works quickly to reverse the main life-threatening processes of anaphylaxis: it constricts blood vessels to raise blood pressure and reduce swelling, relaxes bronchial smooth muscle to improve breathing, and decreases mucosal edema that can obstruct the airway. In a five-year-old, the recommended dose is 0.01 mg/kg of a 1:1000 solution given intramuscularly, typically in the mid-thigh. This immediate treatment helps prevent progression to airway compromise or shock, even if airway symptoms aren’t yet present.

Antihistamines like diphenhydramine and steroids such as dexamethasone can help with itching or delayed reactions, but they do not reverse the acute airway or hemodynamic changes quickly enough and are not first-line in the emergency management of suspected anaphylaxis. Administering them first would delay potentially life-saving epinephrine.

So, the best initial action is giving intramuscular epinephrine promptly, followed by close monitoring, airway support as needed, fluid management, and rapid transport to a higher level of care.