Seafood Allergy

As concerns about dietary fat and cholesterol have increased both in Europe and the United States, seafood has become a more prominent component of the diet. In 1990 consumption of seafood in the USA reached 15lbs per person per year, while world consumption averaged 29 lbs per capita.

Scientists classify seafood as in the table below.

Seafood Classification

Phylum	Class	Common Name
Molluscs	Gastropods Bivalves Cephalopods	Snail, Abalone Clam, Mussel, Oyster Octopus, Squid, Scallop
Athropods	Crustacea	Crab, Lobster, Shrimp, Prawn, Crayfish
Chordates	Cartilagenous Bony Fish	Fish Ray, Shark Cod, Salmon,Tuna etc.

Of the three phyla of seafood, crustacea are recognised as a common cause of food hypersensitivity in food-allergic individuals.

The pattern of symptoms following ingestion of crustacea is similar to that reported for other foods, including, nausea, sickness, diarrhoea, abdominal cramps, wheezing, rhinitis, flushing, urticarial rashes and dramatic swelling. Fatal reactions have been reported.

Some patients even report that the smell of crustacea during cooking causes a problem, and laboratory studies have shown that shrimps and other crustacea retain their ability to cause allergic reactions despite being boiled.

Patients with a history of severe reactions to crustacea should avoid locations where these are cooked, as these sensitive patients may indeed react to allergens present in the vapours from the cooking shellfish. Crustacea-allergic individuals should also be cautions when eating squid and oyster as some preliminary scientific studies have shown that there may be some cross-sensitivity with these foods. Although a number of patients with fish allergy also report a sensitivity to crustacea, recent reports appear to indicate that this is probably two different allergies existing concurrently and not a cross-reactivity between the fish and crustacea.

Currently, the only accepted therapy for food allergy is strict avoidance of the offending food. Patients who have food-induced life-threatening reactions need to be instructed by their doctors in the use of selfinjectable adrenaline, which they should carry with them at all times. Additionally, it is a good idea for such patients to wear identification bracelets such as Medic Alert bracelets stating their food sensitivity, which will help health care professionals to treat any life-threatening reactions if the patient is too ill to give a history themselves.

Not surprisingly, the prevalence of occupational disease in fish and seafood handlers is quite marked. Among these workers, skin reactions from contact with shellfish are some of the most commonly reported. It has been estimated that up to one-third of food handling caterers who suffer from skin disease of this type have to find alternative employment because of the severity of their symptoms. Workers who are employed in the processing of shellfish also often suffer from asthma, rhinitis and conjunctivitis. Scientific investigations have shown that even five years after leaving the industry symptoms still persist in a majority of workers with occupational asthma due to shellfish. The problems seem to be cause by either cooking steam or aerosolized tiny particles of shellfish. One group of prawn workers in England developed occupational asthma six weeks after the method of extracting the prawns was changed from hand peeling to air blowing by machine. Most of the symptoms disappeared again after the compressed air jets were replaced with cold water jets.

Based on results of scientific studies in Canada, which up to 16% of workers processing snow crabs developed occupational asthma, it appears that a significant number of workers in the shellfish processing industry in the United States and Europe are at risk of developing occupational disease.

Based on an article by Doctors Musmand, Daul and Lehrer,Tulane University School of Medicine, New Orleans, USA (Clinical and Experimental Allergy 1993,Volume 23, Pages 722-732) - Checked 5/2008