Around 13% of children in Switzerland are affected by atopic dermatitis. Cutaneous defects with increased water loss and allergens permeability are hallmark of the disease. The prevalence of food allergy in children with moderate-to-severe atopic dermatitis is estimated to be 34%, mostly to eggs, milk and peanuts. Food allergy can cause immediate reactions with urticaria and anaphylaxis or delayed flares of eczema. In older patients and adults, exposition to respiratory allergens (dust mites, pollen) can also cause an exacerbation of the eczema. Allergy testing identifies patients with atopy, who are at greater risk of rhinitis and asthma. Skin prick tests, in vitro tests and food challenges can identify a concomitant allergy, leading to specific allergen avoidance mea-sures potentially improving skin symptoms.