Safety of Mixed Tree Nut Oral Food Challenges in the Management of Multi-Tree Nut Allergic Children and Adolescents

Tree nut (TN) allergic individuals are often sensitized to multiple TN, which can result in multiple, potentially high risk diagnostic oral food challenges (OFC). We report safety and utility of mixed-TN OFC (MTN-OFC) in the evaluation and management of TN allergy. Multi-TN allergic individuals age 3-21 years (n=44), actively restricting multiple TN in diet were evaluated for MTN-OFC eligibility using combination of clinical history and TN-specific IgE, SPT. MTN-OFCs included a 3 TN combination of either walnut, pecan, almond, cashew, hazelnut, pistachio, Brazil nut or pine nut (10g by weight of each TN) administered in incremental doses. Phone surveys ≥ 6 months after passing MTN- OFC evaluated TN dietary incorporation. In 44 subjects (63% male) undergoing MTN-OFC, 77% (n=34) passed; 30/34 who passed (88%) incorporated all TN into diet while 4/34(12%) added tested TN only. Of those who failed (n=10) the majority reported mild-moderate symptoms; no epinephrine doses required. Almond, pecan, cashew and walnut were most commonly included TN. Median TN-specific IgE values prior to MTN-OFC were almond 0.35, cashew 0.35, pecan 0.35, walnut 0.57, pistachio 0.56, hazelnut 0.64. Comorbid atopic disorders included allergic rhinitis (65%), atopic dermatitis (58%), and other food allergies (78%). Long-term follow-up surveys (>6mo) are ongoing, the majority (73%) surveyed to date continue to tolerate dietary TN. MTN-OFCs have a favorable safety profile and reduce the number of single-TN OFCs when performed in carefully selected individuals. Further investigation is important to understand the predictors of MTN-OFC outcome and long-term TN dietary incorporation.