Hives are usually triggered by an allergic reaction to a substance that you encountered or ingested. Because of the allergic reaction, your body releases a protein called histamine, which in turn causes itching, swelling, redness and many other signs and symptoms. A few of the typical triggers of hives are specific foods (nuts, chocolate, fish, tomatoes, eggs, fresh berries and milk), latex, chemicals, pollen, food additives, animal dander, contaminations, medications, and insect bites or stings.
All fruits and vegetables contain some amount of vitamin C. Foods that tend to be the highest sources of vitamin C include green peppers, citrus fruits and juices, strawberries, tomatoes, broccoli, turnip greens and other leafy greens, sweet and white potatoes, cantaloupe and spinach. Vitamin C helps promote a healthy immune system and releases antihistamines. Green tea is also reported to have an antihistamine effect.