Allergy to cooked white potatoes in infants and young children: A cause of severe, chronic allergic disease

Background: Cases of allergy to cooked potato in children have been reported, some with immediate and others with late reactions. The clinical effects of chronic allergic reactions to potato and the effectiveness of diet on such reactions have not been described previously. Objective: We sought to evaluate the importance of cooked potato as an allergenic food in individual cases of atopy in children. Methods: Eight atopic children were selected on the basis of suspicion of allergy to cooked potatoes: all had potato-specific IgE, 2 of 8 had experienced immediate allergic reactions, and 6 of 8 had eczema that improved with a potato-elimination diet (decrease in severity scoring of atopic dermatis [SCORAD] index of >50%). The patients were evaluated by using skin prick tests with homemade cooked and noncooked potato extracts and with a commercial extract and by using IgE immunoblots from SDS-PAGE patterns of potato extract. Seven patients were challenged with cooked potato. The control group consisted of 9 age-matched atopic children, 8 of them with eczema. Results: The mean SCORAD index decreased from 43.3 before to 11.5 after elimination of potato from the diet. Potato CAP values ranged from 3.71 to greater than 100 kUa/L. Potato challenge results were positive in 7 of 7 patients. Skin prick test responses were positive for cooked potato extracts in 7 of 7 patients, for noncooked extracts in 7 of 7 patients, and for the commercial extract in 8 of 8 patients compared with in 0 of 9, 1 of 9, and I of 9 subjects in the control group, respectively. During immunoblotting, 8 of 8 patient sera recognized one or more protein bands compared with 0 of 9 control subject sera. Conclusion: Allergy to cooked potatoes is a cause of severe allergic disease, with immediate reactions and eczema in some atopic infants and young children.