Shellfish Allergy: What Are the Symptoms?
Shellfish: A Common Food Allergy
Shellfish allergies are fairly common and can be serious.
The Centers for Disease Control and Prevention (CDC) says that crustacean shellfish are one of eight foods or food groups that make up 90 percent of all serious allergic reactions in the United States.
Click through the slideshow to learn more about shellfish allergies, tips on spotting shellfish allergy symptoms and serious allergic reactions, and what foods to avoid.
What Is a Shellfish Allergy?
When we talk about shellfish, we mean seafood like shrimp, crab, and lobster. Octopus and squid are also counted as shellfish.
Some people with a shellfish allergy are allergic to all kinds of shellfish. They might need to avoid all seafood. Others only have an allergic reaction to certain shellfish, such as shrimp.
Even a tiny bit of shellfish can be enough to give some people a serious allergic reaction.
Who Can Suffer from a Shellfish Allergy?
Anyone can have a shellfish allergy, but some people are more likely to have one more than others.
According to the Mayo Clinic, adults tend to be more likely than children to suffer from a shellfish allergy. Among adults, women are more likely to suffer than men.
Children can still develop a shellfish allergy. When this happens, boys are more likely to suffer than girls are. You’re also more likely to develop a shellfish allergy if other people in your family have a food allergy.
Mild Symptoms of a Shellfish Allergy
An allergic reaction usually starts as soon as you've touched or eaten shellfish. Not every reaction is the same, but common mild symptoms of a shellfish allergy can include:
- itchy skin
- a tingly feeling in or around the mouth
- red, itchy spots known as hives
- an upset stomach
- a runny or stuffy nose
Obvious Symptoms of a Shellfish Allergy
Some shellfish allergy symptoms are easier to spot than others. Swelling often happens during a shellfish reaction. This might mean your lips, tongue, or even throat swell up. Some people also experience swelling of the face or other body parts.
Other symptoms can include:
- stomach cramps
These symptoms are not considered life threatening, but you should still bring them to the attention of your doctor.
Signs of a Severe Allergic Reaction
A shellfish allergy can cause a severe reaction known as anaphylaxis. This condition is a medical emergency. If you’re suffering anaphylaxis, you need an injection of epinephrine (adrenaline) and other emergency care.
You may be suffering an anaphylactic reaction if you spot any of these danger signs:
- a swollen throat
- difficulty breathing
- a big drop in blood pressure
- a racing pulse
- dizziness or passing out
An Allergic Reaction or Food Poisoning?
Many of the symptoms of an allergic reaction to shellfish match symptoms that are common in food poisoning, but there’s one important difference: a food allergy will usually occur each time you come in contact with the food trigger. Food poisoning is usually a one-off.
If after eating shellfish you find that you are often experiencing symptoms, you might have an allergy.
Treatment for a Shellfish Allergy
Many of the mild symptoms of a shellfish allergy can be treated with over-the-counter antihistamines. These drugs will help calm symptoms such as itching and discomfort.
If you have a severe reaction, you’ll need a shot of epinephrine. You should also go to the emergency room.
If you've been diagnosed with a shellfish allergy and already have an auto-injector, make sure you know how to use it at the first signs of a serious reaction.
Avoiding Products Containing Shellfish
Some shellfish products are hard to spot. They might include:
- fish stock, which is used in many Asian food dishes
- surimi or fake crab, which often contains shellfish meat
- glucosamine, which is a popular supplement made using crustacean shells.
According to the American Academy of Allergy, Asthma & Immunology (AAAI), people with shellfish allergies can still use some glucosamine products. However, as with all supplements, it's best to ask your doctor for advice.
Living with a Shellfish Allergy
There’s no cure for a shellfish allergy, but there are steps that can keep you safe and enjoying life. Here are some tips:
- Cut out shellfish foods.
- Don’t share food.
- Carry your shellfish allergy medication with you at all times.
- Make sure you know how to use your autoinjector if you have one.
- Make other people aware of your allergy by developing an emergency plan and wearing medical bracelets.
If you’re unsure whether something contains shellfish, don’t eat the food in question. It’s not worth risking your life.
- Food Allergies in Schools (2013, October 31), Centers for Disease Control and Prevention. Retrieved on November 11, 2013, from: http://www.cdc.gov/healthyyouth/foodallergies/.
- Hives and Angioedema Description (2010, December 21), Mayo Clinic. Retrieved November 12, 2013, from: http://www.mayoclinic.com/health/hives-and-angioedema/DS00313.
- Shellfish Allergy Diet (n.d.), Johns Hopkins Medicine. Retrieved on November 11, 2013, from: http://www.hopkinsmedicine.org/healthlibrary/conditions/adult/allergy_and_asthma/shellfish_allergy_diet_85,P00034/.
- Shellfish Allergy is not a Shell Game (n.d), American Academy of Allergy, Asthma & Immunology. Retrieved on November 11, 2013, from http://www.aaaai.org/conditions-and-treatments/library/allergy-library/shellfish-allergy-can-be-dangerous.aspx.
- Shellfish Allergy Risk Factors (2011, June 23), Mayo Clinic. Retrieved on November 11, 2013, from: http://www.mayoclinic.com/health/shellfish-allergy/DS00987/DSECTION=risk-factors.
- Shellfish Allergy Symptoms (2011, June 23), Mayo Clinic. Retrieved on November 11, 2013, from: http://www.mayoclinic.com/health/shellfish-allergy/DS00987/DSECTION=symptoms.