Prevalence of corn allergy determined by Double-Blind Placebo-Controlled (DBPC) study
L. TANAKA1, M. Aresery, C. Olmos, M. McCants, L. Wild, J. El-Dahr, and S. Lehrer. (1) Allergy and Clinical Immunology, Tulane University, 1700 Perdido St., New Orleans, LA 70112
Allergy to corn has not been reported frequently in the medical literature. No Double-Blind Placebo-Controlled Food Challenge (DBPCFC) studies exist.
The objective of the study design was to determine the prevalence of corn allergy.
Patients, aged 5 to 65, with a history of adverse reactions to corn or corn products and a positive skin prick test (SPT) to corn allergen, were recruited nationwide. Preliminary questionnaires were sent to the 207 subjects who met study criteria. Fifty-nine secondary questionnaires were returned, 26 were eligible. Seventeen of 19 scheduled subjects completed the challenge. Three were excluded due to negative skin tests to corn prior to the challenge. Repeat SPT was performed prior to the DBPCFC using standard extracts for histamine, PBS (negative control), corn, corn pollen, wheat, soy, peanut, milk, shrimp, egg, rice, oat, rye, and 10 environmental allergens. Extracts of cooked corn, raw corn, corn pollen, lentil (placebo), and the challenge vehicle (apple juice, applesauce, peach puree, and sugar) were prepared on the challenge day using incremental doses of powdered corn (2g, 8g, 16g, 32g). Placebos were prepared identically using lentils. Asymptomatic subjects received doses every 30 minutes until 58g (of corn or lentils) was consumed. Without reaction, subjects rested for 2 hours prior to the next 4 doses. If no objective reactions were observed at the end of the DBPCFC, open challenges were done with corn chips followed by popcorn. Subjects without reactions were considered negative.
Five patients had positive challenges, two during the blinded portion, three with the open challenge. Reactions included: anaphylaxis, urticaria, conjunctivitis and rhinorrhea, perioral urticaria and edema, and wheezing (>15% decrease in peak flow). Anaphylaxis and urticaria occurred during the blinded portion; other reactions occurred during the open challenge.
This study indicates that although corn allergy may be rare, when it occurs it can be severe.
Session 44G, Toxicology & Safety Evaluation