Contributing Author: Gentle Heron
The last time I ate shrimp tempura was 20 years ago. Suddenly, and surprisingly, my lips started to swell, my face to get itchy, and my heart to pound. I had developed a shellfish allergy. I have not dared to try to eat shellfish since that day.
Shellfish include shrimp, lobster, crab, clams, scallops, mussels and squid. Finned fish (such as salmon, cod, tuna and catfish) are grouped with shellfish as seafood. Shrimp are the type of shellfish that most commonly cause an allergic reaction. Not everyone who is allergic to shellfish is also allergic to finned fish, and vice versa.
Shellfish or seafood allergies can be life-threatening. The victim’s body reacts to proteins in the shellfish or seafood and causes a sudden anaphylactic reaction. Minor reactions can be skin rashes and itchiness. More severe reactions can lead to low blood pressure, asthma, or swelling of the throat so severe that breathing is difficult. Severe anaphylactic reactions must be treated in the emergency room.
Many myths exist about shellfish and seafood allergies. Let’s look at some of them.
- Myth: Shellfish allergies begin in childhood.
- Fact: Allergic reactions can occur at any age, and the initial occurrence can be severe. Unfortunately, people do not generally outgrow allergies to shellfish, and it is not unusual for someone to be allergic to many kinds of shellfish.
- Myth: It’s the iodine people are allergic to.
- Fact: Although shellfish and seafood contain iodine, that is not what causes allergies. It is specific proteins in the shrimp or codfish, called allergens for the reaction they cause.
- Myth: You can’t have a CT (computerized tomography) scan because you’ll be allergic to the contrast dye.
- Fact: The content of the contrast dye used in CT scans is not related to the allergens in shellfish. Although some people do have a reaction to contrast dye, it is unrelated to allergies to shellfish or seafood.
- Myth: Avoid foods that contain carrageenan.
- Fact: Carrageenan is a food additive made from a type of algae or seaweed. It is common in dairy products and other household items. It is not associated with seafood allergies.
- Myth: You have to actually eat the seafood to get an allergic reaction.
- Fact: The allergens in seafood can be transmitted in steam from cooking fish or shellfish, and can cause an allergic reaction in those who are sensitive. This is why people who are severely allergic to shellfish or seafood must avoid restaurants where it can be smelled.
For information about shellfish allergies:
For information on seafood allergies: