Food allergies occur when your immune system reacts soon after you eat a certain food. If you suffer from food allergies, you can have pain abdomen, diarrhea, vomiting, hives, swollen lips or itching in the mouth. About 6-8% of children below 3 years of age suffer from food allergies but they improve as they grow older. Risk factors for food allergy are family history, already suffering from other allergies, younger age group (children, toddlers & infants) and asthma.