Allergic diseases are an adverse reaction of the immune system against otherwise innocuous substances and are characterized by their high complexity. Patients can be asymptomatic or their involvement could be as severe as asthma. The complex nature of the phenotypes involved seems to point to genetic and environmental factors implication. Familiar aggregation or genetic implication in the development of these diseases is well reported, and experts seem to agree that atopic diseases affect homozygotic twins more than dizigotic twins (Ownby, 1990, Duffy et al., 1990)
