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Keywords:

  • allergic rhinitis;
  • Gammarus;
  • seafood

R hinitis and bronchial asthma due to seafood ingestion or exposure to seafood cooking vapors are common among patients suffering from seafood allergy ( 1) and among workers exposed to Crustaceae in their work environment ( 2). We report the first case of respiratory allergy to the shrimp Gammarus used as food for a pet turtle, although there has been a previous report of occuptional asthma caused by this genus when processed as fish food ( 3).

A 25-year-old womanpresented 3 years ago with allergic rhinitis and mild, intermittent bronchial asthma, with sensitization to Dermatophagoides pteronyssinus. She controlled her symptoms with intermittent use of inhaled terbutaline and nasal budesonide. During the last few months, her nasal symptoms had increased, with watery rhinorrhea, sneezing, eye and nose itching, and daily nasal blockade. She did not improve with the recommended treatment (nasal steroids and oral antihistamines). She had stated that she bought a pet turtle 2 years before, and fed it with dried shrimp (Gammarus). She used to tolerate seafood ingestion, as well as exposure to cooking vapors of Crustaceae and Mollusca.

Skin prick tests were carried out with common seafood allergens such as shrimp, prawn, clam, and mussel (commercial extracts and/or prick-by-prick with fresh food) with negative results. Skin prick tests with Gammarus extract (ALK-Abelló, SA, Madrid, Spain) showed a 45×60 mm wheal-and-flare reaction, accompanied by systemic symptoms, such as watery rhinorrhea, sneezing, and eye and nose itching, which needed treatment with oral antihistamines. The same extract from Gammarus was tested on 10 seafood-allergic patients, with negative results.

Serum specific IgE against Gammarus by RAST (ALK-Abelló, SA, Madrid, Spain) was positive (class 3). A pool of sera from atopic patients was used as a control, with negative results. No specific IgE against Crustaceae or Mollusca could be detected in the patient's serum.

Immunoblotting ( Fig. 1) showed a diffuse IgE-binding area in the Gammarus extract, with three bands of greater intensity of approximate mol. masses of 25, 32, and 40 kDa. No IgE binding was detected with shrimp extract.

image

Figure 1. Immunoblotting results. Lane 1) Negative control with pool of atopic sera; 2) patient's serum incubated with shrimp extract, no IgE-binding areas; 3) patient's serum incubated with Gammarus extract, with three bands of approximate mol. masses of 25, 32, and 40 kDa.

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After avoiding exposure to Gammarus, the patient improved, reverting to her usual condition (sparse, mild respiratory symptoms).

We report the first case of allergic rhinitis from sensitization to Gammarus used as turtle food. The patient, like most seafood-allergic patients in Spain ( 1), was allergic to Dermatophagoides. Cross-reactivity between both species seems to depend on tropomyosin ( 4), which is the major allergen in Crustaceae. However, in this case, the allergen seemed to be different, in that there was no IgE-binding band of 35 kDa (tropomyosin), that no IgE-binding was detected with shrimp extract, and that the patient tolerated seafood ingestion, as well as exposure to cooking vapors of Crustaceae and Mollusca.

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Footnotes
  1. IgE-mediated allergy to dried Gammarus shrimp.