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Shellfish Allergy

There are two major categories of shellfish: crustaceans and mollusks. Crustaceans include crabs, lobsters, crayfish, shrimp, and more. Mollusks include snails, slugs, mussels, and octopuses. A shellfish allergy refers to an adverse immune response to either category but the crustacean group causes the most severe reactions.

Shellfish cause the most allergic reactions in adults, affecting about 2% of the population. They are also responsible for 0.1% of allergic reactions in children. These adverse immune responses are mainly caused by tropomyosin, a major muscle protein. There are high levels of tropomyosin in shrimp, crab, and lobster, making them the most common offending shellfish.

Since shellfish are often cross-reactive, it is recommended that allergic patients avoid all types of shellfish. The allergists at NY Allergy & Sinus Centers have provided a complete list of shellfish to help you navigate through your allergy with ease.

Types Of Shellfish

Abalone Barnacles Calamari Clams Cockle
Crab Crawdads Crawfish Crayfish Cuttlefish
Ecrevisse Escargot Geoduck Krill Limpet
Lobster Mollusks Mussels Octopus Oysters
Periwinkle Prawns Scallops Scampi Sea Cucumber
Sea urchin Shrimp Snails Squid Whelk

Foods That Could Contain Shellfish

Any food prepared at a seafood restaurant is likely to have cross-contact with shellfish. Some examples are:

Bouillabaisse Cuttlefish Ink Fish Stock
Paella Seafood Flavoring Surimi

Shellfish Allergy Symptoms

  • Tingling or itchiness in the mouth
  • Hives or skin rash
  • Swelling in one place or all over the body
  • Asthma symptoms
  • Tightening of the throat
  • Anaphylaxis

Most reactions occur within 30 minutes of consumption, however, it can take longer for symptoms to appear. Skin reactions can result from touching or simply inhaling the allergen. Asthma symptoms can also appear after inhalation or other exposure to shellfish. For these reasons, you should avoid any activity or restaurant that can expose you to shellfish.

Diagnosing A Shellfish Allergy

A shellfish allergy can be diagnosed with a skin prick test. This allergy test provides a quick and relatively safe way to detect allergies. Our NYC allergists perform this test in our treatment centers throughout Manhattan and Queens. Skin prick testing takes less than 20 minutes to complete.

If you experience the above symptoms after eating shellfish, call our office to confirm your shellfish allergy. In certain situations, symptoms appear due to toxins in shellfish. So you may not be truly allergic. It’s important to get a proper diagnosis to receive the appropriate care.

Treating A Shellfish Allergy

The only proven therapy for a shellfish allergy is avoidance, which is not always possible. In this case, antihistamines can help soothe your symptoms. Contact our allergists for an allergy treatment plan that includes your personalized list of medications to help you feel better.

Patients with a history of anaphylaxis should receive an epinephrine auto-injector. There are many options available, such as Epipen and Auvi-Q. Talk to your doctor about which device is best for you.

Frequently Asked Questions

Is shellfish allergy the same as seafood allergy?

No, shellfish allergy refers to shelled fish while seafood allergy includes shelled and finned fish.

If I’m allergic to shellfish, can I still eat regular fish?

Shellfish and fish are often not related. So being allergic to shellfish doesn’t guarantee a fish allergy. However, always consult with your allergist about possible allergens.

Can individuals allergic to shellfish eat imitation crab?

Imitation crab is made from Alaska pollock which is a finned fish, but some brands do contain less than 2% of king crab. To be safe, avoid imitation crab.

Do shellfish allergic patients react to both categories of shellfish?

Some people with shellfish allergies are allergic to both groups (crustacean and mollusk) while others are allergic to just one. Contact our allergists to determine if you must avoid both categories of shellfish.


The specialists and associates at NY Allergy & Sinus Centers are here to help answer all of your shellfish related questions. We have access to the latest treatment & testing, and we offer convenient asthma & allergy clinics throughout NYC. Our doctors can also help you find relief for your respiratory allergies, nasal and sinus problems, skin conditions, and asthma. We see both adult and pediatric patients. Call NY Allergy & Sinus Centers today at 212-686-4448 to make an appointment.

  • NY Allergy & Sinus Centers

    Our premier team of allergists offer state-of-the-art methods for diagnosis and treatment of allergies and sinus conditions. Our NY Allergy & Sinus Centers perform Allergy Skin and Blood Testing, Food Allergy Testing, Patch Testing, and Immunotherapy, and often a same-day diagnosis is possible.

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