For parents and grandparents alike the rosy cheek appearance of their young child is often considered a sign of vigor. However, data presented at the 2023 American Academy of Allergy, Asthma and Clinical Immunology Annual meeting in San Antonio gives pause to that concept. In a presentation by Professor Alan D. Irvine, co-sponsored by the International Eczema Council, the reason behind these pink cheeks in babies was reviewed. It turns out the production of natural skin moisturizers (factors), derived from filaggrin after birth, are delayed in fully developing in the cheek area until about age 7. As Professor Irvine further discussed, intrinsic filaggrin levels can be genetically low or normal but in both states filaggrin is reduced seasonally and with atopic dermatitis activity. Filaggrin genetic testing is not readily available, but an inspection of the palmar surface for hyper-linearity can give a sign of filaggrin activity, at least in Caucasian and potentially Hispanic/Latin and Asian populations.
With delayed cheek natural moisturizer production, the young child with a genetic potential for atopy has a readily accessible portal (cheeks) for the entry of allergens (and antigens). This cheek vulnerability better explains the outside-in concept for allergen-sensitization and development of early-age facial atopic dermatitis with or with concomitant food allergy. This scenario has been recently discussed and the concept of cheek openness to allergen penetration added to the likelihood of this early-life sensitization happening through facial contact.
Finally, adding moisturizers from birth as a protection against the development of atopic dermatitis has proven minimally successful. A study of high-risk infants for atopic dermatitis (AD) was recruited within four days of birth and randomized 1:1 to either twice-daily emollient application for the first eight weeks of life, using an emollient specifically formulated for dry AD-prone skin or to standard routine skin care. This short-term skin care program reduced the incidence of AD in the first year of life in high-risk infants. The majority of allergen sensitization may occur very early, and longer external application durations are not necessary or counter-productive.
Dr. Hopp has no conflicts of interest to report.
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