Answer: 2. Difficulty swallowing
Explanation: The nurse should identify that difficulty swallowing could indicate an allergic reaction to aspirin therapy. While blurred vision, weight gain, and high blood pressure are all potential side effects of aspirin therapy, they are not typically associated with an allergic reaction. Difficulty swallowing, on the other hand, could indicate a potentially serious allergic reaction known as anaphylaxis. It is important for the nurse to monitor the client closely for signs and symptoms of an allergic reaction and to seek emergency medical attention if necessary.