Shellfish Allergy

Your body's immune system sometimes mistakenly reacts to proteins found in certain seafood. This mistaken reaction is called a shellfish allergy. Shellfish includes creatures like shrimp, crabs, lobsters, squid, oysters, scallops, and snails – both crustaceans (like crabs and shrimp) and mollusks (like oysters and squid).

Shellfish allergies are quite common. Some people are allergic to all types of shellfish, while others are only allergic to specific kinds. The reactions can vary greatly. Some people might experience mild symptoms like a rash (hives), a runny nose, or itchy eyes. However, in some cases, the reaction can be severe and even life-threatening. This is why it's important to be cautious.

If you suspect you might have a shellfish allergy, it's crucial to talk to your doctor. They can perform tests to confirm the allergy. Once confirmed, you can work together to develop a plan to avoid future reactions. This might involve avoiding shellfish altogether or being extremely careful when eating foods that might contain shellfish as an ingredient.

Shellfish allergies often cause symptoms within a few minutes to an hour after eating or touching shellfish. These symptoms can include:

• Skin reactions: Hives (raised, itchy bumps), itchy or irritated skin.
• Respiratory problems: Stuffy nose, wheezing, trouble breathing, coughing, choking, or a feeling of tightness in the throat.
• Digestive issues: Stomach pain, diarrhea, nausea, or vomiting.
• Other symptoms: Swelling of the lips, face, tongue, throat, or other body parts; dizziness, lightheadedness, or fainting.

A shellfish allergy can lead to a serious, potentially life-threatening reaction called anaphylaxis. This reaction happens very quickly, often within seconds or minutes of exposure, and gets worse rapidly. Anaphylaxis is a medical emergency.

What is anaphylaxis?

Anaphylaxis happens when your immune system overreacts to something it mistakenly sees as harmful (like shellfish). This causes a flood of chemicals to be released into your body, leading to a sudden drop in blood pressure and difficulty breathing.

Symptoms of anaphylaxis include:

• Airway problems: Swollen throat or tongue, tightness in the throat that makes breathing difficult, coughing, choking, wheezing.
• Circulatory problems: Shock (a sudden drop in blood pressure), rapid or weak pulse.
• Skin reactions: Severe rash, hives, itching, or swelling.
• Digestive issues: Nausea, vomiting, or diarrhea.
• Other symptoms: Dizziness, lightheadedness, or fainting.

What to do if you think you're having an anaphylactic reaction:

• Get immediate medical help. Call emergency services (like 911) immediately.
• Use an epinephrine (adrenaline) auto-injector (if prescribed). This is a medicine that can help stop the reaction. Follow the instructions on how to use it carefully.
• Go to the emergency room. Even if you feel better after using the epinephrine, you still need to be monitored and treated by medical professionals.

When to see a doctor:

If you experience food allergy symptoms soon after eating, especially if you've never had them before, it's important to see a doctor or allergy specialist. They can help determine the cause of your symptoms and recommend appropriate treatment and prevention strategies.

If you have a severe allergic reaction (anaphylaxis), get immediate medical help. This is a serious emergency.

If you think you're having an allergic reaction to food, see a doctor or allergist right away. This is especially important if you feel unwell soon after eating something.

Food allergies happen when your body's immune system, which is meant to protect you from harmful things, mistakenly sees a harmless food as a threat. This trigger, called an allergen, sets off a chain reaction.

For example, in a shellfish allergy, your immune system identifies a specific protein in shellfish as dangerous. Your body's defense system, trying to fight this perceived threat, produces antibodies called immunoglobulin E (IgE). These antibodies are like tiny soldiers that are ready to attack the allergen. The next time you eat shellfish, these IgE antibodies alert your immune system to release chemicals like histamine into your bloodstream. This release causes the unpleasant symptoms of an allergic reaction.

Different types of shellfish contain different proteins. Crustaceans include crabs, lobsters, crayfish, shrimp, and prawns. Mollusks include squid, octopus, mussels, snails, clams, oysters, abalone, and scallops. A crustacean allergy is often the most common type of shellfish allergy. However, some people are only allergic to one kind of shellfish, while others need to avoid all shellfish.

It's important to remember that a fish allergy (like to salmon, tuna, or catfish) is different from a shellfish allergy. Someone allergic to shellfish might also be allergic to fish, or they might only be allergic to shellfish. The best way to know what you can eat safely is to talk to your doctor or other healthcare professional. They can help you figure out what foods are safe for you.

Shellfish allergies are more likely to develop if allergies run in your family. This means if you have a family history of allergies, like hay fever or asthma, you might be more prone to developing a shellfish allergy.

Anyone can develop a shellfish allergy, but it's more often seen in adults. In fact, it's one of the most frequent food allergies in grown-ups. When it comes to adult shellfish allergies, women are slightly more likely to be affected than men. And among children, shellfish allergies are slightly more common in boys than girls.

A severe shellfish allergy can be very dangerous. It can cause a serious allergic reaction called anaphylaxis, which could even be deadly.

Some people with a shellfish allergy are more likely to have a life-threatening reaction (anaphylaxis). This includes people who:

• Have asthma: Asthma can make allergic reactions worse.
• Are extremely sensitive to even tiny amounts of shellfish: This means their bodies react strongly to very small traces of shellfish.
• Have had anaphylaxis caused by food in the past: If you've had a severe allergic reaction to food before, you're at a higher risk of having one again.
• Have a strong family history of allergies: If close relatives have allergies, you might be more prone to them too.

Anaphylaxis needs immediate medical attention. The treatment is a shot of epinephrine (adrenaline). If you're at risk for a severe shellfish allergy reaction, it's crucial to always carry an epinephrine auto-injector (like Auvi-Q, EpiPen, or others). This device allows you to give yourself a dose of epinephrine quickly if you need it. Keep the epinephrine auto-injector with you at all times, just in case.

If you're allergic to shellfish, the only way to prevent a reaction is to completely avoid all shellfish and anything made with it. Even tiny bits of shellfish can cause a serious reaction in some people.

Eating Out Safely: When eating at restaurants, be very careful. Ask about the cooking equipment and utensils used for shellfish. If they are used for other foods, there's a risk of cross-contamination. This might mean avoiding seafood restaurants entirely, as cross-contamination is more likely there.

Protecting Yourself Beyond the Plate: You might need to stay away from places where shellfish are prepared or processed. Some people have reactions even from touching shellfish or breathing in the steam from cooking them.

Food companies are required to list any product containing shellfish (like shrimp, crab, lobster) on the label. This is a good safety measure for people with allergies. However, this labeling isn't required for all types of shellfish, such as clams and oysters. So, it's important to read labels carefully.

Emergency Preparedness: If you have a shellfish allergy, talk to your doctor about carrying an emergency epinephrine injection (like an EpiPen) and how to use it. Knowing how to use it properly is crucial in case of a reaction.

Alerting Others: Consider wearing a medical alert bracelet or necklace to let others know you have a shellfish allergy. This can be very helpful in an emergency situation.

Important Note: You don't need to worry about being allergic to iodine or the contrast dye used in some medical imaging tests, even though shellfish contain a small amount of iodine. Shellfish allergy is different from the reactions some people have to iodine or contrast dye.

A common sign of a shellfish allergy in a skin prick test is a small, red, swollen area (like a bump).

To figure out if you have a shellfish allergy, your doctor will first ask about your symptoms and give you a physical check-up. This helps them rule out other possible health problems.

If you've had allergic reactions soon after eating shellfish, this could point to a shellfish allergy. However, similar symptoms can also be caused by something else, like food poisoning. It's crucial to get a proper diagnosis.

The only definite way to know if shellfish is the cause of your symptoms is through allergy testing. Your doctor might suggest one or both of these tests:

• Skin Prick Test: A tiny amount of shellfish protein is gently poked onto your skin (usually on your arm or upper back). Your doctor will watch for a reaction. If you're allergic, a raised, itchy bump (called a wheal or hive) will appear at the spot where the protein was placed. This usually happens within 15-20 minutes. An allergist (a doctor specializing in allergies) is generally best to perform these tests.

• Blood Test: A sample of your blood is sent to a lab. The lab checks for a specific type of antibody your body makes when it encounters an allergen like shellfish. This antibody, called immunoglobulin E (IgE), is a sign that your immune system is reacting to the shellfish proteins.

If the allergy tests aren't completely clear, your doctor might suggest a medically supervised food challenge. This involves carefully introducing small amounts of shellfish while being closely monitored by medical professionals.