Atopic dermatitis is a disorder that affects up to 4.3% of the pediatric population. Its etiology is unknown, but is probably multifactorial. Evidence has been presented to implicate a role for "allergy" in the pathogenesis of AD. Disregarding the myriad of clinical reports, there is sufficient data in the literature to suggest an etiologic role for inhalants (pollen, mold, and dust mite) and foods in some patients with AD. Definitive studies have demonstrated that both inhalant and food antigens can be absorbed rapidly and transported to the skin, where sensitized mast cells can be activated. Controlled challenges have demonstrated skin reactions following exposure to inhalant and food antigens in sensitive subjects. Activiation of mast cells and/or basophils has been shown following oral food challenges in sensitized children with AD. Although sufficient evidence is now available to implicate "allergy" as an etiologic factor in atopic dermatitis, the link between mast cell activation and the development of eczematous skin changes remains to be clearly defined.