Sensitization to peanut, egg or pets is associated with skin barrier dysfunction in children with atopic dermatitis

Abstract

Background: Children with atopic dermatitis (AD) are often sensitized to food and aeroallergens, but sensitization patterns have not been analysed with biologic measures of disease pathogenicity. Objective:We sought to define allergen sensitization grouping(s) using unbiased machine learning and determine their associations with skin filaggrin (FLG) and transepidermal water loss (TEWL) (assesses skin barrier integrity), S100A8 and S100A9 expression (assesses skin inflammation) and AD severity. Methods:We studied 400 children with AD in the Mechanisms of Progression from Atopic Dermatitis to Asthma in Children (MPAACH) cohort to identify groupings of food and aeroallergen sensitizations. MPAACH is a paediatric AD cohort, aged 1-2, recruited through hospital/community settings between 2016 and 2018. We analysed these groupings' associations with AD biomarkers: skin FLG, S100A8 and S100A9 expression, total IgE, TEWL and AD severity.Results: An unbiased machine learning approach revealed five allergen clusters. The most common cluster (N = 131), SPT PEP, had sensitization to peanut, egg and/or pets. Three low prevalence clusters, which included children with allergen sensitization other than peanut, egg or pets, were combined into SPT Other . SPT NEG included children with no sensitization(s). SPT PEP children had higher median non-lesional TEWL (16.9 g/m 2 /h) and IgE (90 kU/L) compared with SPT OTHER (8.8 g/m 2 /h and 24 kU/L; p = .01 and p < .001) and SPT NEG (9 g/m 2 /h and 26 kU/L; p = .003 and p < .001). SPT PEP children had lower median lesional (0.70) and non-lesional (1.09) FLG expression compared with SPT OTHER (lesional: 0.9; p = .047, non-lesional: 1.78; p = .01) and SPT NEG (lesional: 1.47; p < .001, non-lesional: 2.21; p < .001). There were no differences among groupings in S100A8 or S100A9 expression. Conclusions and clinical relevance:In this largely clinic-based cohort of young children with AD, allergic sensitization to peanut, egg, cat or dog was associated with more severe disease and skin barrier function but not markers of cutaneous inflammation. These data need replicating in a population-based cohort but may have important implications for understanding the interaction between AD and allergic sensitization. | 667 SHERENIAN Et Al.

Elevated serum total IgE is associated with eczema exacerbation in children hospitalized for atopic dermatitis

“…As the levels of serum total IgE and age‐adjusted IgE have been correlated directly with AD severity, 9 it is likely that AD inflammation, rather than just skin infection, contributes to the increase in IgE. There is now increasing evidence that IgE sensitization occurs at the skin level in AD 10 . Due to barrier defects, environmental triggers including food allergens, aeroallergens, and S. aureus are capable of triggering AD inflammation, leading to the production of IgE.…”

Food allergy testing in atopic dermatitis

“…A study of 400 children with AD from the Mechanisms of Progression from Atopic Dermatitis to Asthma in Children cohort found that the most common SPT + allergens were egg white, followed by peanut, egg yolk, dog, trees, cat, ragweed, cockroach, mold, dust mite, grass, milk, weeds, soy, and wheat. 18 Children with AD and sensitization to peanut, egg, cat, and dog had a greater baseline skin barrier dysfunction (increased transepidermal water loss and decreased skin FLG expression) in nonlesional skin and AD severity than those with allergy to other allergens or no allergen sensitization. 18 Peanut and egg sensitization may occur through skin exposure in children.…”

“… 18 Children with AD and sensitization to peanut, egg, cat, and dog had a greater baseline skin barrier dysfunction (increased transepidermal water loss and decreased skin FLG expression) in nonlesional skin and AD severity than those with allergy to other allergens or no allergen sensitization. 18 Peanut and egg sensitization may occur through skin exposure in children. 19 , 20 , 21 , 22 , 23 Individuals with AD are more likely to develop peanut sensitizations through skin exposure.…”

Skin barrier defects in atopic dermatitis: From old idea to new opportunity

“…increased TEWL and decreased FLG expression), and more severe disease (SCORAD) was observed in AD subjects who were poly-sensitized (specifically to peanut, egg, cat or dog) than children with no AD or with AD and other allergen sensitizations. 121 Another study found that pediatric AD patients with FA have greater skin barrier abnormalities (increased TEWL, reduced FLG breakdown products and reduced CER [EOS], esterified ω-hydroxy fatty acid sphingosine ceramides/CER [NS], non-hydroxy fatty acid sphingosine ceramides, ratio) as compared to AD without FA or non-AD controls. 122 …”