The development of peanut allergy and the role of environmental exposure

BackgroundThe prevalence of peanut allergy (PA) in children has gradually increased over the years and is now believed to affect 1–2% of all children in Western countries.1–3 This is in conjunction with an overall increase in the prevalence of all food allergies in children in the past two decades.4 In addition, PA remains one of the leading causes of food-induced anaphylaxis5 and has also been shown to be the leading cause of death related to food allergy in a number of countries.6–10 However, it should be noted that death from food allergy still remains uncommon and is, in fact, relatively rare in children.11 Yet the impact of having PA can be enormously burdensome, leading to increased anxiety, the limitation of social activities and an overall reduction in the quality of life for children and their families.12–13As with all food allergies, avoiding the allergen and treating allergic reactions appropriately continue to be the mainstay of managing PA. Work has been done on inducing peanut tolerance by oral immunotherapy (OIT), but its role is limited to increasing the threshold of reactivity to peanut and has not been shown to induce long-term sustained oral tolerance. Anagnostou et al (2014) demonstrated that peanut OIT raised the reactive threshold so that up to 91% of participants could tolerate a daily ingestion of approximately five peanuts.14 However, Vickery et al (2014) showed that only 50% of those who underwent five years of peanut OIT had sustained unresponsiveness (SU) one month after discontinuing OIT.15This leads us to look at ways of preventing PA as this is likely to be the most effective way of reducing its incidence and prevalence. Prevention can be tackled only when there is a thorough understanding of the mechanisms underlying the development of PA. In recent years, a number of studies have brought to the forefront the importance of the role of environmental peanut exposure and the disrupted skin barrier in the development of PA.