Prevalence of atopic dermatitis in infants by domestic water hardness and season of birth: Cohort study
Atopic dermatitis is a chronic skin disorder in which the skin becomes dry, itchy and thickened. Even though it is very common in children, its exact causes are not well-known. Because water is a known skin irritant and the skin of infants are very sensitive, it has been thought that hard water, that is water that contains high calcium carbonate, may be a risk factor. In this month’s issue of JACI, Engebretsen and colleagues investigate whether early exposure to hard domestic water is associated with the prevalence of atopic dermatitis ( J Allergy Clin Immunol 2017; 139(5): 1568-1574 ). To do this, they looked at the Danish National Birth Cohort study which collected nearly 100,000 children born between 1996 and 2002. Out of these, the mothers of 55,092 children completed an interview at 6 and 18 months to get more information on atopic dermatitis. What the authors found was that hard water is associated with a higher incidence of atopic dermatitis. T...