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How To Test For Shellfish Allergy

Diagnostics And Treatment Of Shellfish Allergy

Shellfish Skin Prick Test – 10-9-15 – Food Allergy Testing

People should instantly consult a specialist if any manifestations appear shortly after eating an allergenic product.

The patient can be more or less allergic to certain kinds of seafood, thus, the doctors do tests to indicate which category of seafood should be avoided from the dietary intake:

Skin test: the allergist injects various protein sources under the skin. The bumps on the skin indicate that there is sensitivity to a certain source of protein.

Blood test: blood is tested in the medical laboratory by measuring sensitivity to a diversity of protein sources of seafood.

The basic point the patient must do with an allergy to shellfish is to reject the use of any fish and crustaceans: crab, lobster and shrimp. There are 3 categories of shellfish, which should be avoided:

  • Cephalopods: squid, octopus
  • Gastropods: snail
  • Bivalve molluscs: mussels, oysters, scallops.

The protein that is contained in shellfish can be replaced by the milk, eggs, meat and beans. Iodized food salt can be used as a source of iodine. Essential fatty acids are maintained in nuts, vegetable oils, sprouts and seeds.

The patient needs to keep medicine against allergy to take them if the condition of health worsens after the use of seafood. It must be stressed, that any medications should be prescribed only by the specialist, who appoints the treatment after the diagnostics.

  • Shortness of breath
  • Wheezing or repetitive dry cough
  • Chest tightness

Where To Look For Shellfish

Although there are easy ways to avoid eating shellfish, its still very important to read through food labels to fully avoid any accidental seafood consumption.

Make sure to familiarize yourself with the various types of seafood and shellfish below if you have a shellfish sensitivity:

  • White fish: Examples include cod, plaice, sole, coley, haddock, pollock, monkfish
  • Oily fish: Mackerel, tuna, sardines, anchovies, salmon, pilchards, herring, trout
  • Mollusks: Clams, mussels, oysters, snails, scallops, squid, octopus
  • Crustaceans: Shrimp, Crab, Lobster, Crayfish

How A Food Allergy Doctor Diagnoses A Shellfish Allergy

Shellfish allergies differ from most other food allergies in that they are more prevalent in adults. In fact, an estimated 2% of U.S. adults have shellfish allergies, compared with just 0.1% of young children. However, it is important to contact an allergy doctor if any symptoms are exhibited.

An allergy doctor will ask questions about the allergic reaction, the type of shellfish being consumed and general medical history. Any pertinent details about allergy symptoms and the time between consumption and allergic reaction will be useful. Based on the information provided, your allergist may conduct allergy testing.

  • Skin prick test A substance containing an allergen is placed onto the arm and the top layer is then pricked. If a small red bump appears, this signals an individual is allergic to the substance.
  • Blood test A blood test is a simple process that involves sending a blood sample for laboratory analysis. The level of IgE antibodies helps your allergist make a diagnosis.

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Fish Allergy Symptoms Diagnosis Treatment And Coping

Daniel More, MD, is a board-certified allergist and clinical immunologist. He is an assistant clinical professor at the University of California, San Francisco School of Medicine and currently practices at Central Coast Allergy and Asthma in Salinas, California.

A fish allergy, as opposed to a shellfish allergy, is one in which your immune system reacts abnormally to a finned fish such as tuna, halibut, or salmon. It is a somewhat less common form of food allergy, affecting women more than men and adults more than children.

Fish allergies often develop during early childhood but, in contrast to a milk or egg allergy, usually persist well beyond school age. Symptoms can range from mild to severe and may include skin rashes, respiratory symptoms, gastrointestinal distress, and anaphylaxis .

The allergy is more common in areas where fish is a predominant part of the local diet, such as Scandinavia and parts of Asia. An allergy may not only be triggered by eating fish but by touching fish or consuming foods in which fish byproducts are used.

Causes Of Shellfish And Fish Allergies

Intermittent allergy to shrimp? : Allergies

For all allergies, the immune system reacts to specific allergy triggers . Your immune system produces antibodies that detect the allergen and cause inflammatory reactions and the release of a chemical called histamine. Histamine causes hives, hay fever and other allergic symptoms.The specific molecule in shellfish or fish that triggers your allergy may be present in a range of foods, and you may then have an allergic reaction to all foods containing that molecule. Some people who are allergic to one type of fish may be allergic to another type of fish or they may have allergies to several crustaceans, such as prawn, crab and lobster. This is known as cross-reactivity. Speak to your doctor about cross-reactivity because it is difficult to predict.The list of fish that can cause an allergic reaction is quite long and includes, but is not limited to:

  • barramundi
  • prawns
  • squid.

The Healthy Eating Advisory Service has more comprehensive lists of seafood that can cause an allergic reaction in some people. Visit your doctor for more information.

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Do All Shellfish Cause The Same Reaction

Often, if you have an allergy to one type of shellfish, you will have an allergy to other types. Crustaceans cause more allergic reactions than mollusks.

You might have a reaction after eating lobster, for example, but eat scallops without a problem. If you have symptoms after eating shellfish, talk with your healthcare provider or allergist before eating any type of shellfish.

Complementary Supplements May Contain Fish Or Shellfish

Glucosamine is a natural chemical compound in your body. It also comes in the form of a supplement, which is linked to joint health and may be taken as a supplement by those with arthritis. Glucosamine is derived from the outer coating of a shellfish. In addition, chondroitin derived from shark cartilage may be added to these supplements.

Fish oil supplements go through an extensive process to remove impurities.

These extended processes should eliminate the protein allergen, but this cannot be guaranteed. It is advisable for people with a fish or shellfish allergy to avoid these supplements, as they may still contain small amounts of fish proteins.

Iodine may be found in shellfish and antiseptic preparations, such as Betadine and Povidine. It is also used as a contrast agent for x-ray and imaging in hospitals. Having an Iodine allergy is unrelated to a fish or shellfish allergy where you are allergic to the protein in the food.

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Fish & Shellfish Allergy Treatment

If you have been diagnosed with an allergy to fish or shellfish, the news might be overwhelming. However, this is a common condition that approximately 2,000,000 people in the UK live with.

Treatment usually involves complete avoidance of the allergen but you may also be prescribed emergency epinephrine if necessary. Its an allergy pen that you can use to treat the symptoms of anaphylaxis.

Even though the allergy cant be cured completely, the condition can be managed by amending your diet to exclude fish/shellfish and products containing it. If you are found to be allergic, you should read the Food Allergen Labeling carefully to make sure that there arent any traces of seafood present.

Symptoms Of A Shellfish Allergy Reaction

Agitest Food Allergen Rapid Test – Shellfish (Lab)

Shellfish allergy reactions can range from mild to severe symptoms. The most common symptoms of a shellfish allergy reaction include:

  • Hives or rash
  • Fainting or loss of consciousness
  • Weak, rapid pulse

Anaphylaxis is a medical emergency and must be treated with epinephrine immediately. With severe shellfish allergies, anaphylaxis can occur within minutes. Those with a shellfish allergy are advised to carry two epinephrine auto-injectors to ensure rapid treatment in case of accidental ingestion or contact.

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Will I Need Food Allergy Testing To Diagnose A Shellfish Allergy

After asking you about your symptom history, your provider may do food allergy testing to confirm a diagnosis:

  • Skin prick test: During this in-office test, your provider places a drop of the allergen on your skin and pricks your skin. The drop seeps into your skin. Your provider will confirm a diagnosis if a red, itchy bump appears after 15 to 30 minutes.
  • Blood test: A blood test can help detect whether you have a specific food allergy.

These tests are not conclusive. Together with your symptoms and history, your provider will make a diagnosis.

If I Have A Shellfish Allergy How Do I Take Care Of Myself

You can live a healthy, enjoyable, active life with a shellfish allergy. Take some precautions to keep yourself healthy and feeling your best:

  • Know what youre eating and drinking.
  • Check label ingredients even if its a product youve eaten safely before. Often, manufacturers change recipes, and shellfish may have been added.
  • If your child is allergic, teach them not to accept food from friends.
  • Be restaurant safe: Ask detailed questions about ingredients and food preparation when you eat out.
  • Wear your medical alert bracelet or carry an alert card with you.
  • If your healthcare provider prescribed self-injectable epinephrine, carry it with you at all times. Make sure you have two doses available, as you may need to repeat the injection.

A note from Cleveland Clinic

A shellfish allergy can be annoying. It can interfere with your life, especially if you enjoy eating seafood. Its smart to take precautions and avoid shellfish, even if you only experience mild symptoms. By avoiding shellfish, you can almost eliminate the uncomfortable risks of an allergic reaction. If you notice symptoms after eating shellfish, talk to your healthcare provider or allergist to get a diagnosis. Your provider will talk to you about how to best care for yourself and explain how to use an epinephrine auto-injector.

Last reviewed by a Cleveland Clinic medical professional on 07/30/2020.


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What Is A Shellfish Allergy

A shellfish allergy is a type of food allergy. If you have a shellfish allergy, you experience unpleasant symptoms after eating shellfish.

Shellfish are animals that live in the water and have a shell-like exterior. There are two types of shellfish:

  • Crustaceans: shrimp, crayfish, crab, lobster.
  • Mollusks: clams, scallops, oysters, mussels.

How Can My Child Avoid Shellfish

seafood allergy

Shellfish is easy to avoid. Some foods, such as Worcestershire sauce, steak sauce, fried rice, egg rolls, salad dressings, seafood muffaletta sandwiches can have shell fish as hidden ingredients. Cross contamination when buying fresh shellfish over the counter in shops and supermarkets can occur. Some dishes like paella, bouillabaisse, gumbo and frito misto contain lots of different kinds of fish at once, can be difficult to spot. It is useful to avoid such dishes.

Some face creams and health supplement can have crushed shells and should be watched for.

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Avoiding Shellfish In Restaurants

When going out to eat, it is very important to let the host or restaurant staff know about a food allergy beforehand as there may be a potential risk of cross-contamination of food dishes or cooking materials.

Someone with a severe allergy may even need to stay away from the fumes or vapors that can come out of a kitchen where people are preparing shellfish dishes.

People should not hesitate to let the waitstaff know if that is a potential trigger for an allergic reaction.

Shellfish Allergy Management In Adolescents And Children:

Even though shellfish allergy responses, like other food allergy symptoms, can occur when a kid is not with his parents, parents should ensure that their childs school, daycare, or other program has a written emergency action plan that includes instructions for preventing, recognizing, and managing these incidents in school and during exercises such as sporting events as well as field trips.

After being diagnosed with shellfish allergy following the shellfish allergy test, if your kid has been given an auto-injector, make sure you and those in charge of his or her supervision fully comprehend how to use it.

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How To Spot Shellfish Allergy Triggers

People with a shellfish allergy must be very careful when dining out or exploring an area where shellfish is present. It is important to remember the shellfish protein can cause an allergic reaction through an air-borne manner with the cooking process. You can also have a reaction from simply handling the shellfish or even touching food that has come in contact with shellfish. In some restaurants, the same cooking oil used to fry shellfish products is used for french fries and deep-fried vegetables. Be mindful of the foods served and ask about the preparation and cooking processes.

Food Labels

Some foods have shellfish products as ingredients such as bouillabaisse, fish stock, surimi, and natural and artificial flavorings. The Food and Drug Administration requires food labels to list the top eight allergens that are associated with 90% of the food allergens. Shellfish is one as well as soy, wheat, eggs, peanuts, tree nuts, fish and cows milk.

These products must be listed in a separate section of the food label to alert consumers with allergies. However, there is no law stating labels must alert if food products are processed in a facility containing any of these eight allergens. Some companies have taken the initiative and separated the processing units to be able to have it shown on their food products.


Keeping A Record Of Your Symptoms

Food Allergy 101: Shellfish Allergy | Shellfish Allergy Symptom

Diagnosing an allergy can be difficult. If you think you or a child in your care may have an allergy, keeping a record of symptoms can help you and your doctor to understand what is causing them.Your diary could include information about whether the symptoms occur:

  • inside your home, outside or both
  • for a short time or longer
  • at night, during the day or when you wake up
  • after you have had a particular food or drink
  • after you have taken a particular medication, either prescription or over the counter from a pharmacy or supermarket
  • after you have taken a herbal medicine.

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What Are Shellfish Allergies

Although most major food allergies begin in childhood, one allergy in particular stands apart: shellfish. An allergy to shellfish may develop any time during a persons life, but tends to present in adulthood. It can be caused by foods that youve eaten before with no issues.

Along with fish, shellfish allergies are the most common adult-onset food allergies. Its estimated that more than 6.5 million American adults have allergies to one or both, according to Food Allergy Research & Education .

There are two kinds of shellfish, crustaceans and mollusks. Here are a few examples of crustaceans to watch out for if youre allergic:

  • shrimp
  • snails
  • scallops

Most people who are allergic to one type of shellfish are also allergic to the other type. Theres a chance you may be able to eat some varieties. However, doctors usually recommend that people with shellfish allergies avoid all varieties to be safe.

A shellfish allergy is different from other allergies in other ways, as well. For example, allergic reactions to shellfish are unpredictable, sometimes occurring long after a person has consumed the allergen and has shown no other symptoms. Allergic reactions to shellfish also often become more severe with each exposure.

What Are Symptoms Of A Shellfish Allergy

Shellfish allergy symptoms range from mild to severe. One person may experience itching and hives while another could have a life-threatening reaction, such as breathing problems. Symptoms can affect many different parts of the body: skin, respiration, digestion and heart.

Shellfish allergy symptoms include:

  • Tingling or swelling of the lips, tongue or throat.
  • Chest tightness, wheezing, coughing, shortness of breath and difficulty breathing.
  • Stomach issues: pain, nausea, indigestion, vomiting or diarrhea.
  • Dizziness, weak pulse or fainting.
  • Pale or blue skin coloring.
  • Anaphylaxis, a severe, potentially fatal allergic reaction, often involving several parts of the body.

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Iodine And Shellfish Allergy: A Myth That Lingers

Close to 3% of the U.S. population is allergic to shellfish, according to the Journal of American Medical Association. For those affected, even a small bite of shrimp, lobster, or crab, can result in reactions from itching and hives to anaphylaxis.

The protein tropomyosin is considered to be the main allergen in shellfish allergy. Its a myth that people allergic to shellfish are allergic to iodine, according to the American Academy of Allergy, Asthma, and Immunology. The myth lingers and continues to have an impact on patients and their healthcare, as iodine is a component in intravenous dye which is widely used for radiological procedures.

A study published in the medical journal Allergy, Asthma Proceedings demonstrated that allergic patients themselves are not well informed. The study enrolled 60 subjects with a confirmed shellfish allergy. When asked the source of the shellfish allergy, 92% answered iodine.

Gupta, R. M.D., M.P.H., Journal of the American Medical Association, Prevalence and Severity of Food Allergies, Faber, M.A. M.D., Pascal, M. M.D., et. al., Allergy, Shellfish Allergens: Tropomyosin and Beyond, Huang, S.W. M.D., Allergy, Asthma Proceedings, Seafood and Iodine: An Analysis of a Medical Myth, American College of Allergy, Asthma, and Immunology, Is Shellfish Allergy Related to Iodine?

What Else Should I Know

Peanut and fish allergy due to platelet transfusion in a child

If allergy testing shows that your child has a shellfish allergy, the doctor will give you guidelines on keeping your child safe. To prevent allergic reactions, your child must not eat shellfish. Your child also must not eat any foods that might contain shellfish as ingredients. Anyone who is sensitive to the smell of cooking shellfish should avoid restaurants and other areas where shellfish is being cooked.

For information on foods to avoid, check sites such as the Food Allergy Research and Education network .

Always read food labels to see if a food contains shellfish. Manufacturers of foods sold in the United States must state whether foods contain any of the top eight most common allergens, including crustacean shellfish. The label should list “shellfish” in the ingredient list or say “Contains shellfish” after the list.

Some foods look OK from the ingredient list, but while being made they can come in contact with fish. This is called cross-contamination. Look for advisory statements such as “May contain fish,” “Processed in a facility that also processes fish,” or “Manufactured on equipment also used for fish.” Not all companies label for cross-contamination, so if in doubt, call or email the company to be sure.

Cross-contamination often happens in restaurants. In kitchens, shellfish can get into a food product because the staff use the same surfaces, utensils , or oil to prepare both shellfish and other foods.

Other things to keep in mind:

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