D2.276 - Clinical and Immunological Differences in Shellfish Allergy

Shellfish allergy represents a frequent cause of food-induced anaphylaxis. Its prevalence varies according to geographic and dietary factors. In Spain, it is the third most common cause of food allergy in adults.

Two cohorts were analyzed: one with limpet allergy (n = 66) and another with crustacean allergy (n = 29). Clinical history, prick-by-prick testing with raw and cooked shellfish, and specific IgE to snail or shrimp were evaluated. Molecular diagnosis was performed using the ALEX® platform.

Patients with limpet allergy had a mean age of 27 years and showed universal sensitization to Dermatophagoides spp. Anaphylaxis (66.7%) and bronchospasm (19.7%) predominated, with a mean latency of 128 minutes. Prick-by-prick testing was positive in 61% of cases with both raw and cooked limpet. Mean total IgE was 491.97 IU/mL, and specific IgE to snail was 0.55 kU/L. Molecular analysis (n = 52) identified Cra c 6 (troponin C) as the most frequently recognized allergen, detected in five patients.

In the crustacean group, the mean age was 28 years (62.1% female), with sensitization to Dermatophagoides spp. in 96.6% of patients. Urticaria/angioedema (58.6%) and anaphylaxis (13.8%) were the most frequent clinical manifestations, with a mean latency of 20 minutes. Prick-by-prick testing was positive in more than 83% of cases. Mean total IgE was 666.11 IU/mL, and specific IgE to shrimp was 1.06 kU/L. Molecular analysis (n = 21) revealed recognition of tropomyosin in seven patients and troponin C in nine.

Reactions to crustaceans are generally more rapid, whereas those induced by limpets are delayed and associated with greater clinical severity. Diagnostic tests show higher performance in crustacean allergy. In both cohorts, troponin C was the most frequently recognized allergen, contrasting with previously published data.