NUT Co Reactivity ‐ ACquiring Knowledge for Elimination Recommendations (NUT CRACKER) study

Background Ambiguities exist regarding the diagnosis of tree‐nut allergy, necessitating either their elimination or the performance of oral food challenges (OFCs). Objective To examine the coincidences of allergies among tree‐nuts and improve diagnostic testing to minimize the need for OFC. Methods Eighty‐three patients prospectively evaluated for walnut, pecan, cashew, pistachio, hazelnut, and almond allergy. A history of previous reactions was obtained, and standardized skin prick tests (SPTs) using finely ground tree‐nut solution and basophil activation tests (BAT) were performed. Patients underwent OFC for each tree‐nut they eliminated and to which a reaction in the previous 2 years was not documented. Results While most patients were sensitized to 5‐6 tree‐nuts, over 50% were allergic to only 1‐2 tree‐nuts. The highest rate of allergy in sensitized patients was observed for walnut (74.6%) and cashew (65.6%). The rate of co‐allergy for most tree‐nuts was