Lower occurrence of atopic dermatitis in children thanks to farm animals and cats

Atopic dermatitis (also known as atopic eczema) is a chronic and extremely painful inflammation of the skin that frequently occurs in early childhood, generally already in infancy. Up to 20 percent of all children in industrialized countries are affected, making it one of the most common childhood skin diseases.

The need to better understand this disease is all the greater considering the intense suffering it causes in small children. Atopic dermatitis is, however, an allergic condition and all allergic reactions result from complex interactions of genetic and environmental factors on the immune system. Earlier research has already indicated that allergies are less common in children who grow up on farms and whose mothers live on farms during their pregnancy. Exposure to farm animals and bacteria frequently found in farms as well as drinking milk from the dairy offer the immune system protection. However, proof of this protective effect in connection with atopic dermatitis has remained elusive.

Now, the «Journal of Allergy & Clinical Immunology» (JACI) has published a study by Caroline Roduit from the research team of Roger Lauener, University of Zurich.

The study analyzes how prenatal environmental factors and genetic mechanisms influence the development of atopic dermatitis during the first two years of life. The authors of the study examined children in rural areas of five European countries: Austria, Finland, France, Germany and Switzerland. Of the 1,063 children taking part in the study, 508 were from families that lived on farms, 555 were not farm children.

The researchers were able to demonstrate that women who spend their pregnancy in the proximity of farm animals and cats have children with a reduced risk of developing atopic dermatitis in their first two years of life. The research team also identified two genes in these children that are of vital importance for innate immunity and was able to link the expression of these genes to a lower likelihood of a doctor diagnosis of an allergic condition. The findings of the study are not only significant in the face of the frequency of the disease and the suffering it causes: They also support the theory that gene-environment interaction with the developing immune system influences the development of atopic dermatitis in young children.

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Literature:

Caroline Roduit, MD, MPH, Johanna Wohlgensinger, PhD, Remo Frei, PhD, Sondhja Bitter, MD, Christian Bieli, MD, PhD, Susanne Loeliger, Gisela Büchele, MPH, Josef Riedler MD, Jean-Charles Dalphin, MD, PhD, Sami Remes, MD, Marjut Roponen, PhD, Juha Pekkanen, MD, Michael Kabesch, MD, Bianca Schaub, MD, Erika von Mutius, MD, MSc, Charlotte Braun-Fahrländer, MD, Roger Lauener, MD, and the PASTURE study group: Prenatal animal contact and gene expression of innate immunity receptors at birth are associated with atopic dermatitis, in: Journal of Allergy & Clinical Immunology (JACI), doi:10.1016/j.jaci.2010.10.010