Letters to the Editor
To the Editor:
We read with interest the review by Iyengar and Walker (1) about the implications of breast milk in the development of atopic disease; however, we strongly disagree in considering children's atopic dermatitis (AD) as an allergic disease.
The majority of cases of AD emerge in the absence of signs of immunoglobulin E–mediated sensitization (2) and many children will not develop it (3). Increasing evidences confirm that AD is the result of a primary epidermal barrier defect, mainly residing in filaggrin abnormalities (4), which increases skin permeability and allows environmental allergens, such as food allergens, to penetrate and stimulate a TH2 immune response (5); the more the skin is altered, the earlier and the stronger the sensitization (6). Nowadays, because of these facts, we must accept that the traditional way to conceive the cause and effect between allergy and AD has been inverted (7).
We believe that future studies about the effects of breast-feeding or of environmental factors, such as hydrolyzed formulas, on the development and expression of allergy should be based on immunoglobulin E–mediated symptoms and not on the evaluation of AD. If breast-feeding has positive effects on the clinical expression of AD, mechanisms other than allergy must be considered.
1. Iyengar SR, Walker WA. Immune factors in breast milk and the development of atopic disease. J Pediatr Gastroenterol Nutr
2. Illi S, von Mutius E, Lau S, et al. The natural course of atopic dermatitis from birth to age 7 years and the association with asthma. J Allergy Clin Immunol
3. Novak N, Bieber T. Allergic and non-allergic forms of atopic diseases. J Allergy Clin Immunol
4. Bieber T. Atopic dermatitis. N Engl J Med
5. Dubrac S, Schmuth M, Ebner S. Atopic dermatitis: the role of Langerhans cells in disease pathogenesis. Immunol Cell Biol
6. Hill DJ, Hosking CS, de Benedictis FM, et al. Confirmation of the association between high levels of immunoglobulin E food sensitization and eczema in infancy: an international study. Clin Exp Allergy
7. Lack G. Epidemiologic risks for food allergy. J Allergy Clin Immunol