Since the latter half of the 20th century, the number of allergy patients has been increasing rapidly, especially in developed countries. In Japan, a country known for its high prevalence of allergies, one in two people is said to have some form of allergy. Recent studies have shown that the rise in the number of food allergy cases in adults are linked to the increase in hay fever. The symptoms include swelling and itching in the mouth and throat. Find out the mechanisms of food allergy in adults and how to prevent it.