Most dermatologists are agreed on the important part played in the patient with atopic eczema by non immunological phenomena such as scratching and mental stress. However, many find it difficult to accept that atopic eczema might be primarily an allergic disease, and some authors virtually discount this possibility (Norins, 1971;Emmerson, 1979). Since the atopic state is by definition an allergic one, and as allergy has been established to play a central role in asthma and hayfever, it would seem improbable a priori that this third major disease of atopic individuals should not result to some extent from allergy. Non-allergic factors such as exercise and psychological infiuences are also aetiologically important in asthma, so that the established role of non-allergic factors in atopic eczema should not prejudice the issue.The question of food allergy has always excited the most interest, and a considerable amotint has been published on the subject. These publications have been concerned with three principal topics: (i) diagnosis of food allergy by skin tests and/or IgE RAST; (2) 'challenge' studies; (3) therapeutic elimination diets. These will now be considered in turn.
Diagnosis of food allergy in atopic eczema by skin tests and/or IgE RASTThe question of the role of IgE antibodies in the pathogenesis of atopic eczema has been discussed in the first part of this article. Until we have a clearer understanding of the precise part played by these antibodies, it will remain difficult to interpret usefully the results of skin tests and in vitro tests such as the RAST. The presence of immediate-type allergy to foods in patients with eczema does not necessarily imply that exposure to these foods causes the disease. Much of the misunderstanding concerning the question of food allergy in eczema hinges on this point. Otir ignorance of the significance of specific IgE antibodies in eczematous patients limits the value of these tests in their management. However, patients with atopic eczema do differ from those with asthma and hayfever in having a generally very much higher frequency of positive immediate skin tests to foods (Barnetson, in press), and much greater 0307-6938/81/0500-0317$02.00