An infant develops widespread urticaria and begins to have respiratory wheezing and tongue swelling after eating peanut butter. What is the nurse's immediate priority?

A. Place child prone and wait for spontaneous resolution: Positioning the child prone does not prevent airway obstruction and delays critical intervention. In cases of anaphylaxis, waiting for symptoms to resolve spontaneously can be life-threatening due to rapid progression of airway compromise. B. Initiate emergency airway management: The infant is exhibiting signs of anaphylaxis, including respiratory wheezing, tongue swelling, and widespread urticaria, indicating potential airway obstruction and systemic reaction. Immediate airway assessment, administration of intramuscular epinephrine, and preparation for advanced airway support are essential to prevent respiratory failure and shock. C. Give oral antihistamine and observe in the room: Oral antihistamines are insufficient in severe allergic reactions. They may help with cutaneous symptoms but do not reverse airway edema, bronchospasm, or cardiovascular collapse, making observation alone dangerous. D. Apply topical hydrocortisone to hives: Topical corticosteroids have no effect on systemic allergic reactions or airway compromise. They are only useful for localized skin inflammation and do not address the life-threatening aspects of anaphylaxis.