Skin Barrier Linked to Childhood Allergies
Research from paediatricians in University College Cork’s School of Medicine has revealed that a weakness of a newborn infant’s skin barrier can help predict which child will develop food allergies, and could in the future be used to intervene to prevent both food allergy and other allergic conditions such as asthma during the course of their childhood.
Published in the world’s leading Allergy journal, the Journal of Allergy and Clinical Immunology, the Irish research shows for the first time that simple non-invasive measurements of skin barrier function in the first few days of life can predict the development of food allergy.
The information was collected by the BASELINE cohort study, jointly funded by Ireland’s National Children’s Research Centre and the UK Food Standards Agency. Recruitment took place in Cork University Maternity Hospital and the follow up visits took place UCC’s HRB-funded Children’s Discovery Centre. Professor Jonathan Hourihane, Head of Department of Paediatrics & Child Health University College Cork, states that “We used simple, non-invasive measurements to support and extend previous human and mouse studies linking eczema/ atopic dermatitis and the transcutaneous sensitisation to food, leading to the development of food allergy in children. We have confirmed that food allergies are associated with skin barrier defects, even in children who do not get eczema and this link can be found even before the newborn baby leaves the maternity hospital. We think this research has great potential in that it not only grants us a platform to comprehend how allergies may start, but should allow us to design and develop further studies and clinical trials in the years ahead which will help us understand how to prevent allergies - right from day 1. These future trials potentially offer hope that the onset of lifelong allergic conditions, which has reached epidemic proportions, may be amenable to simple, early-life preventive strategies.”
Atopic dermatitis (AD) which is also known as atopic eczema, is one of the earliest features of allergies in children. The association between severe infantile AD with food allergy has been well documented. Recruited infants from the Baseline cohort study had Transepidermal Water Loss (TEWL) measured non-invasively at 3 time points in the first year of life. All suspected cases of food allergy were assessed by formal food challenge at 2 years by researchers who were blind to the TEWL data. Of the 1903 Irish newborns recruited 1260 had food allergy assessment and tests at 2 years. Food allergy was challenge-proven in 56 children (4.45%) Newborns with allergic parents whose neonatal TEWL was in the top 25% of readings, (>9gwater/m2/hr) were 18 times more likely to have food allergy at 2 years than children with TEWL in the lowest 25%.
The link of high neonatal TEWL with later food allergy was also seen when the children did not develop AD in the first two years, signifying thatthe physical barrier deficit itself, rather than the actual presence of visible AD or intervening AD-related inflammation which is most important in facilitating early, abnormal immune responses to food allergens such as peanut, egg and milk.
The research indicates that the current research focus on skin barrier preservation in the first few months of life to prevent AD in the first year may have additional and longer term benefits in food allergies and possibly asthma, as they may prevent allergy signals starting in the defective skin of very young babies, even before they get AD.