The association between atopic dermatitis and food allergy in adults

We conducted a systematic literature search for studies investigating the link between atopic dermatitis and food sensitization or clinically significant allergy (FA) in adults, to assess the strength of the association between the two diseases in both general and selected populations.

Around 10% of adults with FA have concomitant atopic dermatitis at the population level. Adult atopic dermatitis patients show much higher rates of sensitization to foods than healthy individuals, in particular to food proteins cross-reactive with airborne allergens, rather than the food allergens that typically predominate amongst children with atopic dermatitis. When food challenges have been performed, rather than relying on questionnaire information and specific IgE testing alone, they often do not confirm eczematous reactions. Only half of patients who have challenge-proven FA improve on a strict elimination diet.

Challenge-proven FA in adults with atopic dermatitis is uncommon. The incidence of new-onset FA in adult atopic dermatitis patients is currently unknown, as are the main routes of sensitization. There is increasing evidence from studies in infants that sensitization to food protein can occur across the skin barrier, in particular in the presence of eczematous skin inflammation. Carefully conducted large longitudinal studies amongst adults that take into account skin barrier function and genetics are required.