Molluscan shellfish allergic reactions

In another Spanish study, Crespo et al. (1995) evaluated 355 children on the basis of clinical history, skin prick tests (SPTs), and specific serum IgE to mollusks. Allergies to molluscan shellfish were noted in 10 of these children or 2.8%. However, mollusks caused 1.6% of 608 allergic reactions among this group of children. 

Individualistic adverse reactions to foods can occur through several different types of mechanisms (Taylor and Hefle, 2001). True allergic reactions can include both IgE-mediated immediate hypersensitivity reactions and cell-mediated delayed h)q5ersensitivity reactions (Taylor and Hefle, 2001). However, only IgE-mediafed reactions have been documented to occur with ingestion of molluscan shellfish in sensifive individuals. 

D. Allergic reactions to specific types of molluscan shellfish... 

Molluscan shellfish allergy has been described in the medical literature to virtually all of the commonly ingested types of molluscan shellfish. The following sections will summarize published reports of allergic reactions to the major categories of edible molluscan shellfish — gastropods, bivalves, and cephalopoda. 

Although bivalves are likely the most frequently ingested class of molluscan shellfish, the existence of allergic reactions to bivalves is rather poorly documented in the medical literature. IgE-mediated allergic reactions to oyster, clam, scallop, mussel, and cockle have been reported as described below. 

The tropomyosins of mite and insect species show some sequence identity (63-65%) with snail tropomyosin and share similar epitopes (EFSA, 2006 Fig. 4.1). Still, tropomyosin appears to play a minor role in the crossreactivity of dust mites and snails (Asturias et ah, 2002 Guilloux et ah, 1998 Van Ree et ah, 1996a). Other non-tropomyosin allergens are likely to be involved including Der p 4 (amylase), Der p 5, Der p 7, and hemocyanin (Martins et ah, 2005 Mistrello et ah, 1992 Van Ree et ah, 1996). While snail is the main molluscan shellfish species involved in cross-reactions with dust mites, some patients allergic to dust mites and snails are also sensitized to mussels (DeMaat-Bleeker et ah, 1995 Van Ree et ah, 1996b). In their study of 70 patients sensitized to molluscan shellfish, Wu and Williams (2004) noted that 90% were also sensitized to dust mites. However, the clinical significance of this sensitization was not documented. 

---