True food allergy affects two to four percent of the general population. This incidence is a little higher in infants and young children. The most common foods that cause allergic symptoms are cows milk, eggs, peanuts, soy beans, nuts, seafood, corn and wheat. Symptoms of a true food allergy include hives, swelling of lips or face, shortness of breath, wheezing and running, itchy eyes and nose. Severe food allergy can sometimes lead to shock-like reactions which can be fatal.
Some adults have symptoms of gas, bloating and diarrhea after eating dairy products.
These may be symptoms of lactose intolerance and not a true allergy to milk. A careful history with skin testing of suspected foods will help identify them. Elimination of these foods from the patient''s diet usually helps resolve food allergy symptoms. Hay fever or sinus allergy is caused by contact with allergens such as pollen, dust, mold or animal dander. Such an exposure produces sneezing, congestion, runny and itchy nose, and itchiness in the throat and ear.