Uncertainty surrounding the allergic nature of atopic dermatitis (AD) is evident in the writings of the founders of the modern study of allergic disease. In 1931, Coca described atopic eczema and contact dermatitis in only four pages of his text [1]. He labeled atopic eczema an inherited disease that occurs in individuals with a family history of atopy, or in people who at the same time or later in life had asthma or hay fever. In addition, he emphasized that the application of inciting substance to uninvolved skin in atopic eczema would have no effect; however, intracutaneous injection of the same would result in wheal formation. In 1947, Cooke wrote more extensively but began by stating, “In no important group of commonly accepted diseases of allergy is our knowledge more scanty and more superficial, and the dermatologic and allergic literaturemore contradictory and confusing, than in that group designated as allergic dermatitis” [2]. In general, his comments contradicted those of Coca concerning family history, coexistence with other allergic disease and skin test responses. In