**3. Epidemiology**

Over the past several decades' industrialized nations have seen a dramatic rise in the incidence of AD (Ghazvini, et al. 2010). This disease occurs primarily in childhood affecting 15-30% of children and 2-10% of adults. It most frequently begins in early childhood with 45% of cases occurring within the first six months of life and 85% of cases diagnosed within the first five years (Bieber, 2008).
