What is shellfish?
They are aquatic invertebrate animals, edible. They include crustaceans with more than 50,000 species such as shrimp, lobster, lobster, prawn… and molluscs made up of more than 100,000 species of bivalves (clam, mussel, oyster), cephalopods (octopus, cuttlefish, squid) and gastropods (snail, limpets). Not necessarily if you have an allergy to one of them, you have to have them all.
Shellfish are one of the most frequent causes of food allergy, its prevalence is linked to the frequency of its consumption.
Can you get a “shellfish allergy”?
The answer is YES. It is a hypersensitivity reaction with an immune mechanism, usually mediated by an antibody called IgE, which develops after ingestion, contact or inhalation of vapours from these foods.
Shellfish allergy is also considered an occupational disease that is, people who work in a food industry, due to the frequent handling of these foods, they can develop allergy.
Who is responsible?
Shelfish proteins are the allergens that cause allergy. Among these proteins we have Tropomyosin. It is a contractile protein, that is, it intervenes in the contraction of the muscle cells of all species of invertebrates. Allergenic tropomyosins have been described in numerous invertebrate species: crustaceans, molluscs, arachnids (dust mites) and cockroaches.
If you have a shellfish allergy, you may become allergic to dust mites or vice versa. But it is not necessarily a condition to have both allergies Remember that immune, genetic, and exposure factors are involved for an allergy to occur.
Other causative allergens are: arginin kinase,myosin light chain, calcium-fixing protein, hemocyanin, paramyosin.
What symptoms can you have?
The most frequent allergic reactions to shellfish are those mediated by IgE, usually occurring whitin the first hour of exposure to the food. The most frequent symptoms are on the skin (hives, itching, erythema, angioedema); digestive, respiratory or all symptoms can also occur, which is what we call anaphylaxis.
What should you do if you’ve had suspicious symptoms of shellfish allergy?
You should go to an allergist. Initially, a detailed medical history of what has happened will be made and according to its assessment it will determine to carry out allergy tests: prick test and a blood test if necessary. It is also possible that an oral provocation test will need to be performed and the study of other shellfish other than the one involved should be evaluated to rule out or diagnose cross-reactivity which may happen because shellfish share homologous allergenic proteins.
If you are already diagnosed with shellfish allergy, what should you do?
You should avoid exposure to shellfish and if you have an accidental exposure follow the instructions of your allergist.
It usually consists of medication with antihistamine, corticosteroids and / or adrenaline as the case may be.
Dra Jaritzy Negrín González.