What action should the nurse take first for a patient who developed itching and swelling after allergen testing?

In cases where a patient develops itching and swelling after allergen testing, the immediate concern is the potential for an anaphylactic reaction. Administering epinephrine is the most critical and urgent action to take. This is because epinephrine acts quickly to counteract the severe, potentially life-threatening effects of anaphylaxis, such as airway constriction, vascular collapse, and shock. It works by causing vasoconstriction, increasing heart rate, and dilating the airways, which can alleviate the symptoms of an allergic reaction.

While applying topical hydrocortisone may help with localized itching and inflammation, it is not sufficient in addressing systemic reactions or preventing the progression to anaphylaxis. Monitoring for lower extremity edema could be relevant but does not address the immediate risk posed by the reaction. Inquiring about exposure to new lotions or soaps is more of a diagnostic measure rather than an urgent response to the symptoms already manifesting after the allergen test. Thus, the priority must be to stabilize the patient’s condition by administering epinephrine first.