Epidemiology: international point of view, from childhood to adults, food allergens.

Recent studies have suggested that the prevalence of food allergy is increasing in many parts of the world. However, many epidemiology studies have been based only on questionnaires without objective testing. The data from these studies do show that the pattern of food allergies is different across the world. In general, studies using objective testing reported a lower prevalence than those without objective testing. The most common food allergens are cow's milk, hen's egg, wheat, fish, shellfish, peanuts, and tree nuts. Recent evidence also suggested that some of these allergies might not persist longer than the childhood years. However, unlike milk and egg allergies, seafood allergy is more likely to persist into adulthood. Peanuts and tree nuts are some of the most common causes of anaphylaxis in developed countries, but these are rather rare in developing countries. Given the early evidence of an increasing prevalence of food allergies, continual monitoring of the changing prevalence and patterns in different countries should help us understand the true causes of food allergy.