This study evaluates the diagnostic efficacy of CAP System (capsulated hydrophilic carrier polymer) for recombinant tropomyosin from shrimp extract in discriminating between subjects allergic to shrimp with CAP positive subjects allergic to mites, crustaceans asymptomatic but with a positive CAP to shrimp, to identify those at greatest risk of food reactions.

Most epidemiological data related to allergy to shellfish come from the USA, where 2.5% of the adult population is subject to an allergy to shellfish, which is also the leading cause of anaphylaxis in adults in these areas. This allergy affects also the European adult population, so that the crustaceans were included in the European Directive 2003/89/EC on the labeling requirement to indicate any allergenic ingredients (listed in Annex 3 a) used in the production of a food and present, although in other form, in the finished product. The allergen mainly involved in allergic reactions to shellfish food is the tropomyosin protein of PM of about 34-36 kDa, isolated for the first time in the shrimp (Pen to 1), involved in the mechanisms of muscle activation and identified in the muscle fiber of many crustaceans (Pen i 1, Cha f 1, Cra c 1, Hom a 1, v 1 Lit, Pan s 1, Pen m 1) and molluscs (Hel as 1, d 1 Hal, Cra g 1, Oct 1 st, Tod p 1). The tropomyosins, identified in many other invertebrates, such as dust mites and cockroaches, seem to be cross-reactive with each other, suggesting the role of allergens inside of the Invertebrates. In those circumstances, the positivity of specific IgE for the crustaceans can thus be determined also by sensitization to tropomyosin even for simple cross-reactivity with tropomyosin of the mites, which represents a minor allergen Der known as p10.

Inclusion Criteria:

• males and females aged between 18 and 80 years;
• Patients with clinical manifestations have been discovered and documented allergy to shrimp and / or mite in which both demonstrated IgE-mediated mechanism (CAP System for shrimp and / or mite positive);
• patients with questionable symptoms to shellfish are tested for unleashing double-blind placebo-controlled trial with shrimp and when clinical manifestations are enrolled;
• all patients with these characteristics will necessarily have to sign the informed consent for inclusion in the study.

Exclusion Criteria:

• Women who are pregnant;
• patients chronically treated with antihistamines or steroids;
• those who deny consent to participate.

Will be selected a group of patients (group A) consisted of 50 subjects with a history of allergic reactions to shellfish, both slight localized to the oral cavity than severe systemic, these patients will show positive IgE to the extract of whole shrimp. In this group may also be included subjects with symptoms and circulating IgE positive for dust mites, both symptomatic and asymptomatic