Fish – Shellfish Allergy

Overview of a Shellfish Allergy

A fish or shellfish allergy is very common and can be extremely life-threatening. If you are allergic to fish, it does not necessarily mean that you will also be allergic to shellfish, and vice versa. Symptoms can range from mild to life-threatening. In some instances, it is best to avoid places with these items altogether.

  • In adults, shellfish is one of the more common lifelong food allergies. Children are not typically allergic to shellfish, but the allergy tends to develop later in life.
  • Fish and shellfish are not related, meaning that you may be allergic to one and not the other. Also, you may be allergic to one type of fish but not others. Your allergist can help you narrow it down. On the other hand, a shellfish allergy usually means you should avoid them all.
  • Even the smallest amount of fish or shellfish can cause life-threatening reactions. The chance of cross-contamination at restaurants is very high and should be taken seriously.
  • Salmon, tuna and halibut are the most common fish that people are allergic to.

Symptoms of a Shellfish Allergy

An allergic reaction to fish and shellfish will generally occur within minutes or an hour of ingestion. Minor symptoms may include: hives, swelling of lips, face, tongue and throat, wheezing, trouble breathing, abdominal pain, nausea, diarrhea, dizziness and fainting. Allergies also have the potential to be life-threatening. If an anaphylactic reaction occurs, a dose of epinephrine and a trip to the emergency room is necessary.

Causes of a Shellfish Allergy

A fish or shellfish allergy occurs when the immune system overreacts to the protein that is present in fish or shellfish. The second time that you come into contact with the allergen, your body may produce histamine that causes the allergic reaction.

Risk Factors of a Shellfish Allergy

If food allergies are common in the family, you are at a greater risk to have an allergy to fish or shellfish. An allergy to fish or shellfish is most common in adults, but can occur in children. In adults, women are more susceptible to the allergy, while in young children, boys are more susceptible. If you have asthma or a history of food-induced anaphylaxis, you are at a higher risk for a life-threatening reaction.

Complications of a Shellfish Allergy

You may experience extreme reactions if you have asthma or a history of food-induced anaphylaxis. If you experience anaphylaxis, a dose of epinephrine must be administered. Speak with your physician about an action plan.

Prevention of a Shellfish Allergy

The best way to treat a fish or shellfish allergy is to avoid it altogether. It is important to ensure that there is no cross-contamination if you are eating in a restaurant, as even the smallest exposure can lead to extreme symptoms. If you are unsure, inform your server. Read labels carefully, as it can often be found in items such as seafood flavorings. In extreme instances, you may need to avoid places where fish and shellfish are prepared or processed, as some people can have a reaction to just touching or smelling it.

Diagnosis of a Shellfish Allergy

Diagnosing a fish or shellfish allergy can be complicated because symptoms vary in each person. Once an allergy is suspected, schedule an appointment with your allergist. The allergist will then begin to ask you a series of questions about what you experienced. To ensure a proper diagnosis, the allergist may proceed to administer a blood test or a skin prick test.

Treatment of a Shellfish Allergy

Once you have a proper diagnosis, creating a treatment plan is the next step. If you are highly allergic, it is important to stay away from fish or shellfish completely. Be sure to check ingredients and verify with whoever is preparing the food that there has not been any cross-contamination. If your allergist deems it necessary, then keeping an epinephrine dose on you at all time may become necessary in emergency situations.

Summary of a Shellfish Allergy

An allergy to fish or shellfish is very common, but the two are not related. If you have a shellfish allergy, it does not typically mean that you also have a fish allergy. Symptoms may include nausea, dizziness or in extreme cases may also lead to anaphylaxis. Your physician will be able to diagnose you after asking a series of questions, and to verify the proper diagnosis, may also administer a skin test or blood test. The best treatment is to avoid the allergen completely.

Shellfish Allergy Diet

Download our helpful Shellfish Allergy Diet guide. Detailed information on foods to avoid.

Fish Allergy Guide

Detailed information on a shellfish food allergy, including unexpected sources of shellfish or fish.

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Shellfish Allergy FAQ

What are the symptoms of fish allergy?

The most common symptoms of a fish allergy are digestive symptoms, hives, swelling, runny nose, tightening of the throat.

How common is fish allergy?

Being allergic to fish is very common in adults. It is one of the top eight food allergies.

Can you become allergic to fish?

A fish allergy can develop at any age, even if you have eaten fish in the past. In some cases, people can outgrow their allergy to fish.

What is it in fish that causes allergy?

The white muscle tissue that is found in fish has high levels of parvalbumins. This type of protein causes an allergic reaction.

Can you cure a fish allergy?

There is no cure for a fish allergy, but your allergist will be able to help manage your symptoms. It is important to avoid fish and to manage symptoms if you are exposed.