What You Need to Know About Shellfish Allergies

Shellfish allergies are some of the most common food allergies people can have. Unfortunately, this allergy can often be severe and in some cases, life-threatening.

It is imperative to recognize a shellfish allergy and make appropriate compensations for it as soon as possible. Almost seven million people in the U.S. have a shellfish allergy.

Unlike many common allergies, shellfish allergies are not necessarily present in childhood. In fact, roughly 60 percent of people with this allergy have their first allergic reaction to shellfish in adulthood.

If you are allergic to shellfish, it may not take much shellfish at all for you to have an allergic reaction. You may not necessarily even need to consume shellfish in order to have a reaction to it. You may get a reaction simply by touching shellfish, or by consuming food that has come into contact with shellfish.

Note that finned fish like salmon or trout are not related to shellfish. Therefore, being allergic to shellfish does not mean you are necessarily allergic to fish or other types of seafood. If you suspect you might have an allergy to shellfish, contact your doctor immediately for a proper allergy test and diagnosis.

Types of Shellfish

There are two types of shellfish, and a person can be allergic to one or the other type or both. The most common shellfish allergy is to crustacea. Individuals with this allergy should avoid all foods that contain lobster, crab and shrimp.

Less common but still prevalent is an allergy to mollusks, the other type of shellfish. Mollusks include scallops, oysters, mussels and clams. While you may only be allergic to one of these two types of shellfish, your doctor may recommend you stay away from all types of shellfish depending on the severity of your allergy to avoid the risk of an allergic reaction.

Symptoms of a Shellfish Allergy

Not everyone with a shellfish allergy experiences the most extreme symptoms of anaphylaxis and potential death. Some people experience much milder allergic reactions, such as itching of the mouth or hives. Symptoms of an allergic reaction to shellfish may affect the cardiovascular, gastrointestinal or respiratory system, among others, and can include the following:

  • Vomiting.
  • Indigestion, diarrhea, a stomach ache or stomach cramps.
  • Shortness of breath, repetitive cough and wheezing.
  • Trouble swallowing or a tight and hoarse throat.
  • Pallid or blue skin coloring or weak pulse.
  • Confusion or dizziness.

Diagnosing a Shellfish Allergy

Only a doctor can know for sure whether you have an allergy to shellfish. Diagnosing a shellfish allergy can be difficult as the symptoms and triggers can differ from person to person.

The most common diagnostic test for a shellfish allergy is a skin prick test. This test can deliver results in as little as 15 to 30 minutes. The downside of this test is that, if positive, it can feel uncomfortable when a small allergic reaction appears.

Another option is a blood test that looks for immunoglobulin E (IgE) antibodies specific to shellfish. However, this test is considered less sensitive than the skin test. Additionally, it can take one to two weeks to get the results of a blood test for a shellfish allergy. Finally, you may also be able to identify allergies through a DNA test.

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When you first discuss your concern about being allergic to shellfish with your doctor, he or she is likely to interview you first to find out the details of your experience. Be prepared to tell your doctor the following information:

  • The exact type of shellfish you came into contact with.
  • When, where and how you came into contact with it.
  • The type of reaction you had.
  • How long after coming into contact with the shellfish the reaction began.
  • How long your reaction lasted.

Avoiding Shellfish

If you are allergic to shellfish, the most obvious way to protect yourself from experiencing a potentially dangerous allergic reaction to shellfish is to avoid eating it. When eating out or at another person’s home, ask if the dishes you are being served contain any shellfish.

When purchasing packaged foods to prepare meals at home, read the food labels carefully to make sure they contain no shellfish. Ingredients to watch out for include the following:

  • Shrimp (scampi, crevette).
  • Prawns.
  • Lobster (tomalley, scampi, Moreton bay bugs, langoustine and langouste).
  • Krill.
  • Crawfish (ecrevisse, crayfish, crawdad).
  • Crab.
  • Barnacle.

Shellfish could also be found in surimi, seafood flavoring, fish stock, bouillabaisse, cuttlefish ink and the health supplement glucosamine.

Keep in mind that despite popular misconception, Irish moss, also known as carrageenan, is not a type of shellfish. Instead, it is a marine algae used in many foods as a thickener, stabilizer or emulsifier. Therefore, you should not have an allergic reaction to Irish moss if you are allergic to shellfish.

Since you can have an allergic reaction to shellfish simply from coming into physical contact with it, you should avoid attending fish markets as well. Always be on alert for the risk of cross-contamination. Make sure that the food you eat was not stored with shellfish or cooked on utensils used for cooking shellfish.

Other Ways to Protect Yourself

Besides avoiding shellfish, there are other ways to protect yourself from a shellfish allergy. The most effective way is to empower other people to provide you with assistance in the event that you experience a severe reaction to shellfish and cannot provide your own treatment.

Let your closest family, friends and coworkers know of your allergy, so they can be aware to keep shellfish away from you. Be sure to carry a reference card in your wallet or purse that identifies your allergy and instructs the reader on what action to take should he or she discover you undergoing an allergic reaction to shellfish.

When a person is undergoing anaphylaxis, or anaphylactic shock, the first line of treatment is epinephrine. Therefore, it is also wise to always keep an epinephrine auto-injector, like the EpiPen or similar product, somewhere on your person. Finally, you can control some milder shellfish allergy symptoms with corticosteroids and antihistamines prescribed by a doctor.

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