Mauro Calvani, MD, Iride Dello Iacono, MD, Valentina Giorgio, MD, Stefano Miceli Sopo, Valentina Panetta, MD and Salvatore Tripodi, MD.
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. However, there is no consensus on this issue.
Objective: 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 many useless elimination diets. This model is characterized by a conservative diagnostic protocol and ¡°step-up cow’s milk administered dosing.¡± The secondary aim was to investigate possible factors influencing severe reactions.
Methods: Sixty-six children (median age 1 year, range 1¨C18) with suspected immunoglobulin E (IgE)-mediated cow’s milk allergy performed a conservative oral food challenge (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 the emergence of additional 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 ¡Ý 10 ml.
Conclusions: This new model of oral milk challenge 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 higher than 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.
Antonella Cianferoni, MD, PhD, Jackie P. Garrett, MD, David R. Naimi, MD, Karishma Khullar, BS and Jonathan M. Spergel, MD, PhD.
Background: Skin-prick tests (SPT), food-specific immunoglobulin E level (sIgE) and clinical history have limited value individually in predicting the severity of outcome of the oral food challenge (OFC).
Objectives: To develop a score that accounts for SPT, sIgE and clinical history to predict the risk of severe reaction to the OFC.
Methods: A 5 year retrospective chart review was performed on 983 children who underwent OFC to egg, milk and peanut.
Results: Using multilogistic regression, four major indicators were found to be independently associated with failed OFC: sIgE (odds ratio = 1.04, P < 0.0001) , wheal size of the SPT (OR = 1.23, P < 0.0001), a history of any prior reaction to the food (OR = 1.13, P < 0.01), and a history of a prior non-cutaneous reaction (OR = 1.99, P < 0.01) and three were independently associated with anaphylaxis: wheal size (OR = 1.16, P < 0.001), a history of a prior non-cutaneous reaction (OR = 4.24, P < 0.01), and age (OR = 1.07, P < 0.03). A Food Challenge Score (0–4) was developed which accounted for SPT wheal, sIgE, a history of a prior non-cutaneous reaction, and age. A score of 0–1 had a negative predictive value for multisystem reaction to the OFC: 95% for milk, 91% for egg and 93% for peanut. A score of 3–4 had a positive predictive value for anaphylaxis: 62% for milk, 92% for egg and 86% for peanut.
Conclusions: Severe reaction to milk, egg and peanut OFC can be predicted using a simple score that takes into account clinical data that are commonly available prior to the challenges.