A new model for conservative food challenge in children with immunoglobulin E-mediated cow's milk allergy

BACKGROUND: The diagnostic gold standard for food allergy is an oral food challenge (OFC) with the suspected food. Usually, an OFC is stopped at the onset of mild objective symptoms for fear of severe reactions, but there is no consensus on this issue. OBJECTIVES: To investigate the effectiveness and side effects of a new model of oral milk challenge in order to increase the diagnostic accuracy of cow's milk protein allergy and reduce the number of useless elimination diets. This model is characterized by a conservative diagnostic protocol and "step-up cow's milk dosing." The secondary aim was to investigate possible factors influencing severe reactions. METHODS: Sixty-six children (median age 1 year, range 1-18) with suspected immunoglobulin E (IgE)-mediated cow's milk allergy performed a conservative OFC, i.e., the OFC was continued even in the presence of subjective, even repeated, or mild local or multiple organ objective symptoms. If the first objective reaction occurred when the quantity of milk was > 10 ml, the investigator would decide whether to continue the OFC or prescribe a gradual increase in milk feeding at home. RESULTS: Symptoms developed during the OFC in 42.4% of the children. Local, generalized and severe generalized reactions developed in 11 (16.7%), 11 (16.7%) and 6 (9.1%) children, respectively. Only 14/28 (50%) who developed objective symptoms during the OFC were considered to be affected by cow's milk allergy. In the remaining 14 both subjective and objective symptoms developed and the OFC was continued without further symptoms. Epinephrine was administered to 6 of the 28 children (21.4%) who developed objective symptoms. All but one had subjective symptoms following the early doses of milk, whereas all children who later tolerated milk had their first subjective or mild symptoms following doses > or = 10 ml. CONCLUSIONS: This new model of OFC criteria led to frequent severe allergic reactions; hence its use in daily practice seems inadvisable. However, our study provides evidence that a severe allergic reaction does not invariably occur if, the offending food continues to be administered after the onset of symptoms. If mild symptoms appear at doses > 10 ml, continued milk administration, on the same day or in subsequent days, seems to facilitate the development of tolerance and may reduce the number of useless elimination diets.