Ask The Expert
July 30, 2013
Relationship of Dust Mites and Crustaceans
While it has been reported that up to 15% of patients highly sensitized to dust mites are also sensitized to crustaceans, e.g. shrimp and snails, due largely to the cross-reacting anti-tropomyosin IgE, is there risk of inducing clinically significant allergic reactions to the crustaceans while treating patients with dust mite immunotherapy? Should patients highly allergic to dust mites be advised to avoid eating crustaceans?
By Dr. Enrique Fernandez-Caldas
Drs Wallace and Weiner, our Ask the Expert editors comment:
Dr. Enrique Fernandez-Caldas provides a very complete referenced response [linked below]. We encourage you to read it in its entirety. He concludes by saying:
Based on current evidence, house dust mite allergic patients should not be advised to not eat shrimps, or to stop eating shrimps, based only on positive skin tests, or an in vitro positive specific IgE determination to mite tropomyosin. It should neither be a deterrent for starting mite immunotherapy in well selected mite allergic patients who are sensitized to tropomyosin. A positive specific IgE to tropomyosin could be due to many different factors, including cross-reactivity and co-sensitization. Shrimp allergy in mite allergic individuals could be due to parallel phenomena and not a consequence of each other.
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By Dr. Susanne Vrtala
It has been shown that house dust mite immunotherapy can induce IgE-antibodies to shrimps and snails (1), whereas other studies showed that house dust mite immunotherapy with mite extracts did not induce shrimp allergy (2). The discrepancy of the results might be caused by the house dust mite extracts used for immunotherapy, since it has been shown recently that several commercial house dust mite extracts lack tropomyosin (Der p 10), whereas others contain large amounts of this allergen (3).
Only 10-20% of mite allergic patients are sensitized to tropomyosin (4). House dust mite allergic patients should thus be tested for IgE-reactivity to Der p 10, in order to assess the risk of allergic reactions to crustaceans.
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