Table of ContentsView AllTable of ContentsShellfish TypesSymptomsDiagnosisAvoiding ShellfishFoods Containing ShellfishTips for Eating OutNon-Food SourcesFAQ
Table of ContentsView All
View All
Table of Contents
Shellfish Types
Symptoms
Diagnosis
Avoiding Shellfish
Foods Containing Shellfish
Tips for Eating Out
Non-Food Sources
FAQ
If you’re allergic toshellfish, you need to avoid all shellfish or risk a potentially severe allergic reaction, such asanaphylaxis.This may seem like a simple task if you think you only need to avoid shellfish like lobster, shrimp, calamari, and clams.
However, there are many other types of shellfish, including sea urchins and octopus, that need to be avoided. It is also important to know that people with ashellfish allergymay be able to eat fish without a reaction, and people with afish allergymay be able to consume shellfish.
This article is a comprehensive guide to shellfish. You will learn which foods are shellfish, what restaurant and homecooked meals typically contain shellfish, and how to protect yourself when you have a shellfish allergy.
Verywell / Brianna Gilmartin
Shellfish Types That Cause Allergies
Shellfish are divided into two families—mollusks and crustaceans. It’s possible to be allergic to just one of these two types of shellfish. For example, you might be allergic to crustaceans but not mollusks.
If you’re allergic to one crustacean, you’re likely allergic to all of them. For example, if you’re allergic to crab you’re likely allergic to shrimp too. However, most people who are allergic to one shellfish family are allergic to both.
For this reason, don’t eat any shellfish from either family without talking to your healthcare provider about your allergy first.
CrustaceansCrabCrawfish (crayfish, crawdads)LangoustinesLobsterPrawnsSea urchinShrimpMollusksAbaloneClams (quahogs)CocklesLimpetsMusselsOctopusOystersScallopsSnails (escargot; both sea and land snails)Squid (calamari)Surimi (imitation shellfish, often found in sushi)Whelks
CrustaceansCrabCrawfish (crayfish, crawdads)LangoustinesLobsterPrawnsSea urchinShrimp
Crab
Crawfish (crayfish, crawdads)
Langoustines
Lobster
Prawns
Sea urchin
Shrimp
MollusksAbaloneClams (quahogs)CocklesLimpetsMusselsOctopusOystersScallopsSnails (escargot; both sea and land snails)Squid (calamari)Surimi (imitation shellfish, often found in sushi)Whelks
Abalone
Clams (quahogs)
Cockles
Limpets
Mussels
Octopus
Oysters
Scallops
Snails (escargot; both sea and land snails)
Squid (calamari)
Surimi (imitation shellfish, often found in sushi)
Whelks
Unfortunately, you can’t trust food packaging to warn you about all shellfish.Food labeling laws in the United Statesonly cover crustaceans, not mollusks. Only ingredients made from crustaceans must be identified on labels with an allergy warning. This can be a problem for people who have bad allergic reactions to mollusks.
Most food packaging will highlight (or at least list) mollusk ingredients. By carefully reading the package ingredient list, you should be able to identify mollusk-containing foods.
For example, a jar of white clam sauce almost certainly will contain clams or clam juice. You’ll know to steer clear of it. And fried calamari, also known as fried squid, will include calamari.
Make sure to read food labels carefully. When in doubt, don’t eat the food you’re not sure about.
Imitation Crab Made From Surimi: What to Know
Symptoms of Shellfish Allergy
The crustacean group causes the greatest number of allergic reactions. Shellfish allergy symptoms can include:
Diagnosing Shellfish Allergy
Diagnosing shellfish allergies can be complicated for the following reasons:
If a shellfish allergy is suspected, your healthcare provider will likely refer you to anallergist. To make a diagnosis, allergists will usually do the following:
If you have a shellfish allergy, you’ll need to be extremely careful when dining out. Shellfish are often stored together in restaurants and markets, socross-contaminationbetween crustaceans and mollusks can occur.
You may want to avoid seafood restaurants entirely because people with severe shellfish allergies have had allergic reactions simply from breathing inallergensfrom shellfish that are being steamed, fried, or boiled.
In fact, depending on the severity of your allergy, consider avoiding some types of restaurants and cuisines entirely, such as:
Some restaurants may use shellfish stock as a flavoring or base for sauces or soups. Always tell your server or a restaurant manager about your allergy. Ask them if any items you’re considering contain shellfish.
Restaurants and Allergy Laws
Recipes That Contain Shellfish
By following certain guidelines and preparation,eating out can still be a safeand enjoyable experience. Take these steps to protect yourself:
Non-Food Sources of Shellfish
When you have a severe shellfish allergy, you also need to be aware of potential non-food sources of the allergen. These can include:
Summary
Shellfish allergy can cause severe symptoms. If you’ve been diagnosed with it, you’ll need to carefully avoid all shellfish. This isn’t always easy, since some food ingredients may not be immediately recognized as shellfish.
Carefully reading ingredient labels and understanding which sea animals are classified as shellfish can protect you from accidentally eating it. You may also need to avoid restaurants and certain cuisine that commonly use shellfish in recipes.
Frequently Asked QuestionsAbsolutely. In fact, about 60% of people with shellfish allergies experience their first symptoms in adulthood.One reason may simply be that they, like many children, never tried shellfish until they were older.It’s unlikely. Most people do not outgrow shellfish allergies. However, studies show that 46% of people allergic to shrimp outgrew their shrimp allergy in 10 years.The primary allergen in shellfish is a protein called tropomyosin. Others include parvalbumin and arginine kinase. In all, there are around 20 individual proteins that are potential allergens in shellfish.Learn MoreWhat Causes Food Allergies?It depends on the severity of the reaction. Also, some people have a second wave of symptoms after the first one resolves, called a biphasic reaction, so it’s advisable that someone who has a severe reaction to seafood be observed in a hospital for at least six hours.Keep in mind, too, that symptoms of seafood allergies don’t always occur immediately; it could take several hours for them to develop.Learn MoreHow Anaphylaxis Is Treated
Frequently Asked Questions
Absolutely. In fact, about 60% of people with shellfish allergies experience their first symptoms in adulthood.One reason may simply be that they, like many children, never tried shellfish until they were older.
It’s unlikely. Most people do not outgrow shellfish allergies. However, studies show that 46% of people allergic to shrimp outgrew their shrimp allergy in 10 years.
The primary allergen in shellfish is a protein called tropomyosin. Others include parvalbumin and arginine kinase. In all, there are around 20 individual proteins that are potential allergens in shellfish.Learn MoreWhat Causes Food Allergies?
The primary allergen in shellfish is a protein called tropomyosin. Others include parvalbumin and arginine kinase. In all, there are around 20 individual proteins that are potential allergens in shellfish.
Learn MoreWhat Causes Food Allergies?
It depends on the severity of the reaction. Also, some people have a second wave of symptoms after the first one resolves, called a biphasic reaction, so it’s advisable that someone who has a severe reaction to seafood be observed in a hospital for at least six hours.Keep in mind, too, that symptoms of seafood allergies don’t always occur immediately; it could take several hours for them to develop.Learn MoreHow Anaphylaxis Is Treated
It depends on the severity of the reaction. Also, some people have a second wave of symptoms after the first one resolves, called a biphasic reaction, so it’s advisable that someone who has a severe reaction to seafood be observed in a hospital for at least six hours.Keep in mind, too, that symptoms of seafood allergies don’t always occur immediately; it could take several hours for them to develop.
Learn MoreHow Anaphylaxis Is Treated
8 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Lopata AL, Kleine-Tebbe J, Kamath SD.Allergens and molecular diagnostics of shellfish allergy: Part 22 of the Series Molecular Allergology.Allergo J Int. 2016;25(7):210–218. doi:10.1007/s40629-016-0124-2American College of Allergy, Asthma, and Immunology.Shellfish.Food Allergy Research and Education.Food allergy chef cards.Food Allergy Education and Research.Shellfish allergy.UCDavis Health.What you need to know about shellfish allergy diagnosis, treatment.Ruethers T, Taki AC, Johnston EB, et al.Seafood allergy: A comprehensive review of fish and shellfish allergens.Mol Immunol. 2018;100:28-57. doi:10.1016/j.molimm.2018.04.008Food Allergy Research & Education.Common questions.Australasian Society of Clinical Immunology and Allergy.Allergic and toxic reactions to seafood.
8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Lopata AL, Kleine-Tebbe J, Kamath SD.Allergens and molecular diagnostics of shellfish allergy: Part 22 of the Series Molecular Allergology.Allergo J Int. 2016;25(7):210–218. doi:10.1007/s40629-016-0124-2American College of Allergy, Asthma, and Immunology.Shellfish.Food Allergy Research and Education.Food allergy chef cards.Food Allergy Education and Research.Shellfish allergy.UCDavis Health.What you need to know about shellfish allergy diagnosis, treatment.Ruethers T, Taki AC, Johnston EB, et al.Seafood allergy: A comprehensive review of fish and shellfish allergens.Mol Immunol. 2018;100:28-57. doi:10.1016/j.molimm.2018.04.008Food Allergy Research & Education.Common questions.Australasian Society of Clinical Immunology and Allergy.Allergic and toxic reactions to seafood.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Lopata AL, Kleine-Tebbe J, Kamath SD.Allergens and molecular diagnostics of shellfish allergy: Part 22 of the Series Molecular Allergology.Allergo J Int. 2016;25(7):210–218. doi:10.1007/s40629-016-0124-2American College of Allergy, Asthma, and Immunology.Shellfish.Food Allergy Research and Education.Food allergy chef cards.Food Allergy Education and Research.Shellfish allergy.UCDavis Health.What you need to know about shellfish allergy diagnosis, treatment.Ruethers T, Taki AC, Johnston EB, et al.Seafood allergy: A comprehensive review of fish and shellfish allergens.Mol Immunol. 2018;100:28-57. doi:10.1016/j.molimm.2018.04.008Food Allergy Research & Education.Common questions.Australasian Society of Clinical Immunology and Allergy.Allergic and toxic reactions to seafood.
Lopata AL, Kleine-Tebbe J, Kamath SD.Allergens and molecular diagnostics of shellfish allergy: Part 22 of the Series Molecular Allergology.Allergo J Int. 2016;25(7):210–218. doi:10.1007/s40629-016-0124-2
American College of Allergy, Asthma, and Immunology.Shellfish.
Food Allergy Research and Education.Food allergy chef cards.
Food Allergy Education and Research.Shellfish allergy.
UCDavis Health.What you need to know about shellfish allergy diagnosis, treatment.
Ruethers T, Taki AC, Johnston EB, et al.Seafood allergy: A comprehensive review of fish and shellfish allergens.Mol Immunol. 2018;100:28-57. doi:10.1016/j.molimm.2018.04.008
Food Allergy Research & Education.Common questions.
Australasian Society of Clinical Immunology and Allergy.Allergic and toxic reactions to seafood.
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