Which symptom is characteristic of an allergic reaction?

• A. Hives or local swelling/itching
• B. Nausea and vomiting
• C. Dizziness
• D. Chest pain

Answer: (A)

Allergic reactions commonly show skin involvement with hives and itching, often with local swelling (angioedema) as histamine release from mast cells causes irritation and fluid leakage into tissues. This skin-related sign is the most characteristic feature of an allergic response. Nausea, vomiting, dizziness, or chest pain can appear in some reactions, especially if the reaction is severe, but they are not the defining symptom of allergy.