Determining the parameters to predict allergy in children with pistachio sensitivity

Pistachio and cashew nut belonging to the botanically same family are the tree nuts that induce serious allergic reactions. We aimed to determine the characteristics and the predictors of pistachio and cashew nut allergy in children. For this purpose, we determined SPT, sIgE, and sIgE / Total IgE cutoff values for both pistachio and cashew nut, and created probability curves. Concomitant allergic disorders such as atopic dermatitis, asthma, allergic rhinitis, food allergy, and family atopy were asked. All patients were performed SPT with pistachio, cashew nut, other tree nuts, pumpkin seed, sunflower seed, mango, lemon seed, orange seed, and pollens. Serum of 11 children were collected for the determination of pistachio or cashew nut allergenic protein bands. Among all laboratory and clinical parameters, only SPT wheal size was determined as risk factor for positive pistachio and cashew nut challenge. Area under curve (AUC) both for pistachio and cashew nut SPT was higher than sIgE and sIgE/Total IgE levels. Cutoff values for pistachio SPT, sIgE, and sIgE/Total IgE predicting reactivity were 7.25 mm, 4.14 kU/L, and 1.32%, respectively. Determined optimal cutoff value for cashew nut SPT was 6.25 mm, for sIgE was 1.125 kU/L, and for sIgE/Total IgE was 3.30%. Allergen protein bands for pistahio and cashew nut were not identified to make a clear-cut discrimination between allergic and only sensitized individuals. In conclusion, SPT both for pistachio and cashew nut was the best predictor for OFC positivity. Furthermore, sIgE/Total IgE ratio was stronger and more accurate marker than only sIgE value.