Thirty individuals with history of immediate, objective, adverse reactions after shrimp ingestion underwent double-blind, placebo-controlled shrimp-food challenges. All individuals who did not exhibit a positive response (reproduction of objective symptoms) were administered an open challenge of 16 whole cooked shrimp. Positive challenge responses occurred in 9 30 subjects (30%); six of these subjects experienced a positive response during the double-blind phase. Of the 21 remaining subjects, 12 experienced generalized pruritus as their only symptom, whereas nine subjects had completely negative challenge responses. All placebo challenges were negative. Although a positive skin test was strongly associated with challenge symptoms (p < 0.001), the shrimp prick skin test titration end points were not different among the challenge groups. The serum shrimp RAST percent was significantly higher in the positive challenge group (p < 0.02). Mean levels of shrimp-specific serum IgG, IgA, and IgM levels were not different among the challenge groups. Although no single immunologic variable could be consistently used to identify subjects more likely to exhibit a positive challenge response, the composite of a positive shrimp prick skin test and elevated serum shrimp-specific IgE (RAST percent label bound >11%) demonstrated a correct predictive value of 87% in this group of shrimp-sensitive subjects. © 1988.
Daul, C. B., Morgan, J. E., Hughes, J., & Lehrer, S. B. (1988). Provocation-challenge studies in shrimp-sensitive individuals. The Journal of Allergy and Clinical Immunology, 81(6), 1180–1186. https://doi.org/10.1016/0091-6749(88)90888-3