Mite-induced asthma and IgE levels to shrimp, mite, tropomyosin, arginine kinase and Der p 10 are the most relevant risk factors for challenge-proven shrimp allergy

Background: Shrimp sensitization is common in the general population, but the presence of symptoms is only moderately related to sensitization. A point still at issue is which in vivo and/or in vitro tests (food challenge, component-resolved diagnosis, house dust mite (HDM) sensitization) can help in distinguising shrimp-allergic subjects from subjects that are sensitized but tolerant. Methods: The aim of this study was to evaluate the role of IgE to the different shrimp and mite allergens in distinguishing shrimp challenge positive from challenge negative patients. Subjects with suspected hypersensitivity reactions to shrimp, positive skin prick tests (SPTs) and/or antishrimp IgE were submitted to open (OFC) and double-blind placebo-controlled food challenges (DBPCFC). Specific IgE (sIgE) to shrimp, mites and recombinants rPen a 1, rDer p 1, 2 and 10 were tested by using ImmunoCAP-FEIA. IgE immunoblotting was performed to identify patients' allergenic profile. Results: 13 out of 51 (25.5%) patients with reported reactions to shrimp were truly shrimp allergic (7 DBPCFC positive and 6 with documented severe reactions). These patients had significantly higher skin test wheal diameters than non-allergic patients, as well as higher levels of IgE to rPen a 1 and rDer p 10. HDM-induced asthma and the simultaneous presence of anti-nDer p 1, 2 and 10 IgE levels increased the risk of true shrimp allergy. Conclusion: Food challenge tests are mandatory for the diagnosis of shrimp allergy. Tropomyosin is associated with clinical reactivity. HDM-induced asthma and anti-mite IgE are risk factors for shrimp allergy.