IGHE and atopic eczema: Characteristics of WDEIA patients, diagnosed by oral food challenge: sex, age, BMI, atopic dermatitis, total IgE (KU/L), sIgE (KU/L) against wheat flour, rye flour, gluten, gliadins, ω5‐gliadin, lipid‐transfer protein, dermatophagoides pteronyssinus, timothy grass, birch pollen allergen, cofactor, symptoms, severity according to Messmer and Ring and involved organ systems