What is Seafood Allergy

A seafood allergy is an abnormal reaction to fish or shellfish by the body’s defense system (immune system). If you are allergic to seafood, your body reacts to fish or shellfish as if it is a dangerous substance.

In some cases, a seafood allergy can cause a severe, life-threatening reaction that may make it hard to breathe (anaphylaxis).

A shellfish allergy is one of the most common types of allergy. Shellfish includes crab, lobster, and shrimp. A shellfish allergy often does not start until the person is an adult.

It is less common to have an allergy to finned fish, such as tuna, halibut, or salmon. Often, a fish allergy also does not start until the person is an adult.

What are the causes?

A seafood allergy happens when the immune system sees fish or shellfish as harmful and releases chemicals (antibodies) to fight it.

What are the signs or symptoms?

Symptoms of this condition include:

• Itching or tingling in your mouth.
• Coughing.
• Nasal congestion.
• Sneezing.
• Nausea and vomiting.
• Diarrhea.
• Headaches.

In people with a severe allergy, a life-threatening reaction can occur called anaphylaxis. Get help right away if you have symptoms of anaphylaxis, such as:

• Feeling warm in the face (flushed). This may include redness.
• Itchy, red, swollen areas of skin (hives).
• Swelling of the eyes, lips, face, mouth, tongue, or throat.
• Difficulty breathing, speaking, or swallowing.
• Noisy breathing (wheezing).
• Dizziness or light-headedness.
• Fainting.
• Pain or cramping in the abdomen.

How is this diagnosed?

This condition may be diagnosed based on:

• A physical exam.
• Your medical history.
• Blood tests.
• A skin prick test. For this test, a small amount of a liquid containing an allergy-causing substance is put on your arm.
• A food challenge test. This test involves eating the food that may be causing the allergic response while being monitored for a reaction by your health care provider.

How is this treated?

There is no cure for a seafood allergy. Treatment focuses on preventing exposure to the fish or shellfish you are allergic to and treating reactions if you are exposed to the food. Mild symptoms may not need treatment.

Severe reactions usually need to be treated at a hospital. Treatment may include:

• Medicines that help:
  • Tighten your blood vessels (epinephrine).
  • Relieve itching and hives (antihistamines).
  • Widen the narrow and tight airways (bronchodilators).
  • Reduce swelling (corticosteroids).
• Oxygen therapy to help you breathe.
• IV fluids to keep you hydrated.

After a severe reaction, you may be given rescue medicines, such as:

• An anaphylaxis kit.
• An epinephrine injection, commonly called an auto-injector “pen” (pre-filled automatic epinephrine injection device).

Your health care provider may teach you how to use these if you are accidentally exposed to an allergen.

Follow these instructions at home:

Eating and drinking

• Do not eat the shellfish or fish that you are allergic to.
• Read food labels carefully. Fish and shellfish can be ingredients in sauces, broths, and other products.
• When you eat out, let your server know that you have a seafood allergy. Ask how foods are prepared.

General instructions

• Take over-the-counter and prescription medicines only as told by your health care provider.
• Wear a medical alert bracelet or necklace that describes your allergy.
• Carry your anaphylaxis kit or an auto-injector pen with you at all times. Use them as told by your health care provider.
• Make sure that you, your family members, and your employer know:
  • The signs of anaphylaxis.
  • How to use an anaphylaxis kit.
  • How to use an auto-injector pen.
• If you think that you are having an anaphylactic reaction, use your auto-injector pen or anaphylaxis kit.
• Replace your auto-injector pen immediately after use in case you have another reaction.
• Get medical care after you use your auto-injector pen. This is important because you can have a delayed, life-threatening reaction after taking the medicine (rebound anaphylaxis).
• Inform all health care providers that you have a seafood allergy.
• Keep all follow-up visits as told by your health care provider. This is important.

Contact a health care provider if you:

• Have symptoms that do not go away within 2 days.
• Have symptoms that get worse.
• Have new symptoms.

Get help right away if you have symptoms of anaphylaxis:

• Flushed skin.
• Hives.
• Swelling of the eyes, lips, face, mouth, tongue, or throat.
• Difficulty breathing, speaking, or swallowing.
• Wheezing.
• Dizziness or light-headedness.
• Fainting.
• Pain or cramping in the abdomen.

These symptoms may represent a serious problem that is an emergency. Do not wait to see if the symptoms will go away. Use your auto-injector pen or anaphylaxis kit as you have been told. Get medical help right away. Call your local emergency services (911 in the U.S.). Do not drive yourself to the hospital.

If you needed to use an auto-injector pen, you need more medical care even if the medicine seems to be helping. This is important because anaphylaxis may happen again within 72 hours.

Summary

• A seafood allergy is when your body reacts to fish or shellfish as though they are dangerous substances.
• In some cases, a fish or shellfish allergy can cause a severe, life-threatening reaction that may make it hard to breathe (anaphylaxis).
• There is no cure for food allergies. Treatment focuses on preventing exposure to the food or foods you are allergic to and treating reactions if you are exposed to the food.
• Wear a medical alert bracelet or necklace that describes your allergy.
• Make sure you understand your emergency treatment plan and know how to use the auto-injector pen.