The pathobiology of lesional and non-lesional skin in atopic dermatitis (AD) and the endotypes are poorly understood. Non-lesional skin in atopic dermatitis is an abnormal occurrence.

The Mechanisms of Progression from AD to Asthma in Children (MPAACH) cohort assessed the lesional and non-lesional endotypes of AD, filaggrin (FLG) and alarmin expression, staphylococcal colonization, and patterns of aeroallergen and food sensitization.

Pathophysiologic changes were observed in lesional and non-lesional skin. Non-lesional skin had characteristics of diseased skin that include low FLG and high alarmin expression with increased colonization with S. aureus. FLG expression was related with the development of co-sensitization and moderate-severe AD. Lesional skin was characterized by deficits in FLG expression (p<0.001); however, alarmin expression was the equivalent as seen in non-lesional skin.

The study has revealed that events in the non-lesional skin can promote the successive development of AD severity and co-sensitization. It is an important risk factor for allergic co-morbidities. These data do suggest the incidence of a subclinical eczema endotype that might influence the development of allergic disease in the absence of evident eczema.

Source: Biagini Myers JM, Sherenian MG, Baatyrbek Kyzy A, et al. Events in Normal Skin Promote Early-life Atopic Dermatitis - the MPAACH Cohort. J Allergy Clin Immunol Pract. 2020 Apr 14. pii: S2213-2198(20)30354-8. doi: 10.1016/j.jaip.2020.03.048. [Epub ahead of print]