Final answer:
Antihistamines are the most appropriate treatment for the symptoms of watery, itchy eyes and sneezing caused by an allergic reaction to pollen. Immunotherapy is beneficial for long-term allergy management, but for immediate symptom relief, antihistamines are recommended.
Step-by-step explanation:
The most appropriate treatment for an individual complaining of watery, itchy eyes and sneezing after being given a flower bouquet is antihistamines. This is because the symptoms described are indicative of an allergic reaction, specifically an immediate hypersensitivity reaction to the pollen in the bouquet. Antihistamines work by preventing the histamines released by mast cells from causing inflammation and the resulting unpleasant symptoms like itching and swelling. In the case of severe allergic reactions that escalate to anaphylactic shock, emergency treatment with epinephrine is required, followed by antihistamines and potential use of corticosteroids.