Crustacean allergy

As a rule, seafood is defined as all edible sea animals that are not vertebrates (fish or mammals). Typical seafood are shrimps, crabs, lobsters and crawfish, mussels, water snails and squid. As with fish(see below), their consumption is subject to a typical north-south gradient. Allergies are rather rare in the Central European population. The allergy rate increases in those population groups where the consumption of seafood is more frequent or the rule, for example people living in coastal regions. In southern European countries, seafood is one of the most common causes of food allergies. Occupational contact with seafood can lead to the development of allergic asthma or allergic rhinitis, contact allergic eczema (see below occupational dermatoses) or even food allergies. Besides these IgE-mediated reactions, non-immunological, toxic reactions are also possible.

Currently analyzed and accepted allergens from crustaceans that play a role in human food:

North Sea shrimp (Crangon crangon - North Sea shrimp)

• Cra c 1 Tropomyosin
• Cra c 2 arginine kinase
• Cra c 4 Sarcoplasmic calcium-binding protein
• Cra c 5 Myosin, light chain 1
• Cra c 6 Troponin C
• Cra c 8 Triose phosphate isomerase

Chinese mitten crab (Eriocheir sinensis)

• Eri s 2 ovary development-related protein

American lobster (Homarus americanus - American lobster)

• Hom a 1 Tropomyosin
• Hom a 3 Myosin light chain 2
• Hom a 6 Troponin C

Litopenaeus vannamei (White shrimp) widespread species of farmed shrimp

• Lit v 1 Tropomyosin
• Lit v 2 Arginine kinase
• Lit v 3 Myosin, light chain 2
• Lit v 4 Sarcoplasmic calcium-binding protein

Rose mountain shrimp (Macrobrachium rosenbergii - giant freshwater prawn)

• Mac r 1 tropomyosin

Flagellate shrimp (Melicertus latisulcatus - King Prawn)

• Mel l 1 Tropomyosin

Metapenaeus ensis (shrimp)

• Met e 1 Tropomyosin N.A.

Northern shrimp Pandalus borealis (Northern shrimp)

• Pan b 1 Tropomyosin

Crawfish species (Panulirus stimpsoni - Spiny lobster)

• Pan s 1 Tropomyosin

Aztec shrimp (Penaeus aztecus - shrimp)

• Pen a 1 Tropomyosin

Banana shrimp (Penaeus indicus - Shrimp)

• Pen i 1 Tropomyosin

Black tiger shrimp (Penaeus monodon - Giant tiger prawn)

• Pen m 1 tropomyosin
• Pen m 2 arginine kinase
• Pen m 3 Myosin light chain 2
• Pen m 4 Sarcoplasmic calcium binding protein
• Pen m 6 Troponin C

European swamp crayfish ((Pont-)Astacus leptodactylus (Narrow-clawed crayfish)

• Pon l 4 Sarcoplasmic calcium-binding protein
• Pon l 7 Troponin I

Swimming crab (Portunus pelagicus - Blue swimmer crab)

• Por p 1 Tropomyosin

• Allergies to crustaceans = crustaceans:
  • Crustacean allergy
  • Shrimp allergy
  • Shrimp allergy
  • Lobster allergy
  • Crawfish allergy.
• Crustaceans (shrimps, crabs, lobsters, crayfish and river or edible crabs) are now a relevant source of allergens due to their increasing consumption. Clinically highly acute symptoms can occur; for example, 1-2 g of shrimps can trigger life-threatening reactions in appropriately sensitized individuals. Allergies to crustaceans preferably occur in adulthood and usually persist for life. The clinical symptoms are mainly skin and mucous membrane symptoms ( urticaria, angioedema), followed by food allergies and allergic bronchial asthma. An oral allergy syndrome can be observed relatively frequently. The close relationship of crustaceans is reflected in different, but clinically relevant clinical cross-reactions. Patients with a shrimp allergy to lobster, lobster, crab and house dust mite cross-react. Cross-allergies can also occur between crustaceans and molluscs (e.g. oysters). The 38 kD tropomyosin is also held responsible for this. Concerning the " mite-crustacean-mollusc syndrome" or "mite-shellfish syndrome"; see below house dust mite. Tropomyosin is also responsible for the cross-reactivity between house dust mites, cockroaches and shrimps. Cross-reactions to fish species are not known (see below fish allergy).
• Numerous major allergens have been identified in the group of crustaceans:
  • Shrimp: Met e 1 and Pen a 1
  • Lobster: Hom a 1
  • Crabs: Cha f 1
• These allergens belong to the tropomyosins. Tropomyosins are important muscle structure proteins of all arthropods. Due to the high degree of homology between the different species (shrimps, crabs, lobsters, lobsters, mites, locusts, cockroaches and fruit flies) cross-reactive IgE antibodies may be of clinical relevance (see also However, species-specific sensitisations with isolated reactions to a specific shrimp or crustacean species are also observed.
• Shrimp/crab/shrimp: Shrimps are known to be the most common triggers of an allergic reaction to seafood. The clinical spectrum ranges from generalized urticaria (predominant) to gastrointestinal, respiratory symptoms, non-specific pruritus and oral allergy syndrome. In addition, cases of contact urticaria are known in the processing of raw shrimps. The occurrence of occupational bronchial asthma has also been observed.
• Lobster: As lobster allergens Pan s1 and Hom a1 were found, both tropomyosins, which showed a large agreement with shrimp tropomyosin.
• Molluscs: Food allergies to molluscs are rare. Allergies to squids and snails are allergologically significant. Anaphylactic reactions have rarely been observed. In squid (Todarodes pacificus) a 38 kDa tropomyosin (see above) was identified as the main allergen (death p1). A cross-reactivity to the shrimp antigen Pen o1 was detected. There are indications that molluscs contain a number of other allergens in addition to tropomyosin, but these are insufficiently characterised.
• Molluscs: In addition to type I sensitisations, toxic food reactions, e.g. azaspiracid poisoning, a poisoning with the nerve toxin azaspiracid, with the symptoms diarrhoea, nausea, vomiting, abdominal cramps and chills can mimic an allergic reaction. A microalgae (phytoplankton) is responsible for this. These are small unicellular organisms which, especially in summer, infect mussels, for example. These microalgae produce a large number of highly effective toxins (algal toxins) which accumulate in the mussels.

• Nakano et al (2008) Reactivity of shrimp allergy-related IgE antibodies to krill tropomyosin. Int Arch Allergy Immunol 175-181
• Leung et al (1998) Molecular identification of the lobster muscle protein tropomyosin as a seafood allergen. Mol Mar Biol Biotechnol 7: 12-20
• Worm M et al (2016) Guideline on the management of IgE-mediated food allergies. Allergology 39: 302-344
• Yang AC et al (2010) Measurement of IgE antibodioes to shrimp tropomyosin is superior to skin prick testing with commercial extract and measurement of IgE to shrimp for predicting clinically relevant allergic reactions after shrimp ingestion. J Allergy Clin Immunol 125: 872-878
• Zhang et al (2006): Cross-reactivity among shrimp, crab and scallops in a patient with a seafood allergy. J Dermatol 33: 174-177