Background: The use of allergy tests to guide dietary exclusions for disease control in children with atopic dermatitis (AD) is controversial. We undertook a consensus exercise on how to interpret skin prick test (SPT) results and dietary history for cow’s milk, hen’s egg, wheat and soya in children <2 years old with AD. Methods: Fourteen clinicians from general practice, paediatrics, paediatric dermatology, paediatric allergy and paediatric dietetics from UK and Ireland took part in an online modified Delphi study. Over three rounds, participants gave their anonymous opinions and received individualised and group feedback. The findings were discussed in an online workshop. Results: Of 14 symptoms, 12 were identified as relevant to immediate and 7 to delayed allergy. Regarding SPTs, there was consensus over which allergens to use for wheat and soya but not cow’s milk or hen’s egg; for all study foods, wheal size was determined as 0-1 mm negative, ≥5mm sensitised , but between 2-4 mm categorisation varied by food. During the final workshop, consensus was reached on dietary advice should be given according to SPT results and dietary history. Conclusion: We attained consensus on how SPTs combined with dietary history for four common food allergens should be interpreted in young children under two years of age with AD. These pragmatic recommendations may support clinician education, consistency of decision-making and future research.

Microbial metabolism of specific dietary components, such as fiber, contribute to the sophisticated inter-kingdom dialogue in the gut that maintains a stable environment with important beneficial physiological, metabolic, and immunological effects on the host. Historical changes in fiber intake may be contributing to the increase of allergic and hypersensitivity disorders as fiber-derived metabolites are evolutionarily hardwired into the molecular circuitry governing immune cell decision making processes. In this review, we highlight the importance of fiber as a dietary ingredient, its effects on the microbiome, its effects on immune regulation, and potential mechanisms for dietary fibers in the prevention and management of allergic diseases. In addition, we review the human studies examining fiber or prebiotic interventions on asthma and respiratory outcomes, allergic rhinitis, atopic dermatitis, and overall risk of atopic disorders. While exposures, interventions and outcomes were too heterogeneous for meta-analysis, there is significant potential for using fiber in targeted manipulations of the gut microbiome and its metabolic functions in promoting immune health.