Little is known about possible allergen sources for horses and especially about the responsible allergen molecules,35 including food allergy,3 except in summer eczema, where IgE to Culicoides allergens play an important role.40 While intradermal tests with crude Culicoides whole body often results in positive intradermal test reaction in clinically healthy horses, the use of recombinant Culicoides allergens allows a much more specific diagnosis of summer eczema,47 in clinically healthy, but sensitized horses.48 This evidence concerns the gene IGHE and Eczematoid dermatitis.