Allergic diseases have been increasing progressively over the past few decades. Whilst treatment is important, prevention of allergy remains a critical issue. Professor Gideon Lack’s has been at the forefront of research into the prevention of allergic conditions throughout his career in Allergy. He noted many of his patients with peanut allergy had deliberately been kept away from eating peanut until they inadvertently suffered a reaction on their first known exposure. At the time, many patients in his clinic had also used soaps, oils, and moisturising creams on their baby’s skin to treat their eczema and these products contained peanut oil. Gideon proposed the Dual Allergen Exposure Hypothesis in 1998 in the Lancet and has spent the last 17 years testing this hypothesis. The Dual Allergen Exposure Hypothesis proposes that the development of allergy to foods occur as a result of peanut in oils/creams or the environment penetrating the skin barrier and setting up an abnormal immune response. Normally this would not occur in a baby with normal skin but if the skin is inflamed as with children with eczema, these particles may penetrate the skin. In contrast, it is proposed that early consumption of food proteins such as peanut progress the immune system towards a tolerant response.
The induction of oral tolerance as a strategy to prevent allergies was confirmed in the large randomised controlled trial known as the Learning Early About Peanut study (www.leapstudy.com), recently published in the New England Journal of Medicine. This showed that early introduction of peanut into the diet of babies with severe eczema between 4-11 months of age reduced the development of peanut allergy by 86% compared to those who excluded peanut. These findings have led to health policy changes and it is now proposed that babies with eczema are evaluated by a paediatric allergist to consider early introduction of peanut into their diet and potentially other foods. In the Enquiring About Allergy study (www.eatstudy.co.uk) early introduction of six allergenic foods (egg, milk, peanut, fish, wheat, and sesame) in a group of 1300 babies has been assessed with the aim to reduce the overall burden of food allergic disease; these study results will be published in 2016.
The hypothesis that children become allergic through damaged and inflamed skin has also been investigated by Gideon Lack in several studies. In 2003 Gideon Lack showed that the development of peanut allergy was strongly associated with early eczema and application of skin moisturisers containing peanut oil in a group of over 14,000 children. He then showed, with Dr Helen Brough that exposure to peanut in the environment from household members eating peanut and peanut levels in dust was associated with peanut allergy in children with eczema or who had a genetic mutation (filaggrin) leading to dry, porous skin.
Gideon Lack has shown that previous guidelines to avoid peanut were not only ineffective because sensitisation was occurring through the environment, but also that these guidelines are likely to have been in part responsible for the increase in peanut and possibly other food allergies. This research has opened up new avenues of prevention to try and promote skin barrier function in early infancy and reduce environmental exposures to foods and respiratory allergens as a means to combat the allergy epidemic. Professor Lack and his team are now also working on strategies to treat existing food allergies.