Novel Approaches to Food Allergy
Epidemiological Risk factors and Prevention of Food Allergy
St Mary's Hospital
IgE mediated food allergy occurs in 5-8% of children under the age of 5. The rate of peanut allergy has doubled in the past 10 years. Strategies to date have focused on food allergen avoidance. Numerous studies have taken place over the past few decades (1). All studies which attempted to remove food allergens from the infant's diet or from maternal diet during pregnancy and lactation, have failed to significantly impact on food allergies.
It is unclear whether these methods have failed because of insufficient allergen reduction or simply because oral tolerance to food does not depend on allergen avoidance. More recent work (2) suggests that sensitisation to peanut occurs in children with moderate to severe eczema who are exposed to topical arachis oil in preparation in creams and ointments used in the treatment of eczema and skin rashes. This data suggests that sensitisation may occur to environmental peanut allergens through a disrupted skin barrier.
Peanut allergy is seen only rarely in countries where peanuts are consumed in very significant amounts during infancy, such as in South East Asia and southern Africa . In these countries, infants are typically exposed to large amounts of peanut in the first year of life. Thus, there is a real question as to how peanut allergy arises, and what is the best strategy to prevent the development of peanut and other food allergies? There are 3 possible strategies to consider:
- Early aggressive treatment of eczema to prevent cutaneous sensitisation.
- Complete removal of environmental peanut exposure (topical preparations and foods). This may be difficult to achieve.
- Early high dose introduction to induce oral tolerance.
Randomised controlled interventional studies using these approaches must be carried out if we are to have a basis for future recommendations.
Khakoo GA, Lack G: Preventing Food Allergy. Curr Allergy & Asthma Rep 2004, 4(1): 36-42
Lack G, Fox D, Northstone K, Golding J: Factors associated with the development of peanut allergy in childhood. New Engl J Med 2003, 348: 977-985