Atopic dermatitis and allergy in children: a dynamic relationship.

Atopic dermatitis (AD) is the most common chronic skin disease in children. The defective barrier function of the skin in patients with AD allows foreign proteins to enter the body and interact with components of the innate and adaptive immune systems. The immune response characteristic of AD is complex with the majority of patients making IgE in response to ingested and/or inhaled antigens. Although IgE-mediated mechanisms may represent initial immune responses, they are only one element of a biphasic inflammatory response. Identifying the role of specific allergens in a patient's skin disease is critical yet difficult because diagnostic tests are often not able to distinguish asymptomatic sensitization from true clinical allergy.