Oral desensitisation with food is food-specific and protein-specific.

The avoidance of food(s) is the main therapeutic approach to food allergy. Nevertheless, orally- or sublingually-administered food allergens have gained attention and a number of food-allergic children can tolerate gradually increasing amounts of cow's milk and hen's egg. Our purpose is to show that oral desensitisation with food is an allergen-specific therapeutic approach and for this, we describe 4 illustrative children with IgE-mediated food allergy. The first was allergic to cow's milk and hen's egg, the second to cow's milk, hen's egg and fish. Both underwent oral desensitisation to both cow's milk and hen's egg. The third child was allergic to cow's milk, hen's egg and fish and underwent oral desensitisation with cow's milk. The last child was allergic to raw but not to cooked/boiled hen's egg and underwent the oral desensitisation with hen's egg. The first 2 children reached the clinical tolerance to cow's milk after the cow's milk oral desensitisation, but reached the hen's egg tolerance only after the hen's egg oral desensitisation. Moreover, the second child did not tolerate fish after being desensitised to both cow's milk and hen's egg. The third child tolerated cow's milk, but not hen's egg and fish, at the end of the cow's milk oral desensitisation. The fourth child could tolerate the previously not tolerated raw hen's egg after the oral desensitisation with raw hen's egg. In conclusion, we indicate that oral desensitisation with food is allergen specific. The induction of the clinical tolerance to one food is not followed by the tolerance to the other food(s) that the patient is allergic to. To obtain a double or multiple food tolerance, separate desensitisation protocols, one for each food, have to be carried out. Oral desensitisation with food discriminates between raw and cooked proteins.