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Shellfish Allergy

If you experience vomiting, diarrhea, stomach pain, shortness of breath, cough, chest pain, and swelling on the face, throat, and neck after eating shellfish, it indicates an allergic reaction. Shellfish allergy can turn life-threatening if you do not seek prompt medical attention. Visit allergy and immunology specialists at the Century Medical and Dental Center to have your symptoms accurately diagnosed and treated to prevent painful conditions that can turn serious if they are not addressed timely. The experienced allergy doctors in NYC help detect and fight allergies by determining the type of allergy you have, finding its source, and coming up with the best treatment to help you live a fuller life.

What Is Shellfish Allergy?

Shellfish are one of the most common food allergens. Shellfish allergies occur when the immune system of the body reacts against the proteins present in these animals. When someone with a shellfish allergy gets exposed to the specific protein, it triggers the immune system to fight off this foreign invasion by causing various mild or severe symptoms. This reaction involves the release of histamine, a chemical that causes the symptoms of allergy.

Shellfish allergies are usually lifelong. A majority of people with shellfish allergy experience their first allergic reaction as adults, but shellfish allergy for toddlers and babies is not unheard of.

Shellfish Allergy Symptoms

You are most likely to experience allergic symptoms within minutes to an hour of eating shellfish. The most common symptoms include:

  • Hives, itching, or eczema (atopic dermatitis);
  • Swelling of the lips, face, tongue, and throat, or other parts of the body;
  • Wheezing, nasal congestion, or trouble breathing;
  • Abdominal pain;
  • Coughing;
  • Diarrhea;
  • Nausea or vomiting;
  • Dizziness, lightheadedness, or fainting;
  • Pale or blue discoloration of the skin.

Symptoms of shellfish allergy can vary among individuals and from one reaction to another. Sometimes, a reaction can be very mild and short, while at other times, it can be severe and last longer. The response can also worsen with time which makes it necessary to monitor the symptoms for any changes.
Shellfish Allergy

Complications Resulting From Shellfish Allergy

Severe allergy can lead to a dangerous, even deadly reaction known as anaphylaxis that involves multiple body systems.

Signs of anaphylaxis include:

  • A swollen throat or a lump in your throat blocks the airway constriction and makes it difficult for you to breathe;
  • Shock, with a severe drop in your blood pressure;
  • Dizziness, lightheadedness, and even loss of consciousness.

An anaphylactic reaction to shellfish needs urgent medical treatment with epinephrine injection. You must consult a doctor immediately if you have consumed shellfish and exhibit symptoms of allergies.

What Causes Shellfish Allergy

Food allergies occur as a result of the overreaction of our immune system. In the case of shellfish allergy, our immune system mistakenly identifies a specific protein in shellfish as harmful and triggers the production of antibodies to the shellfish protein or the allergen.

The next time you come in contact with this allergen, your immune system releases histamine and other chemicals that result in allergy symptoms.

Types of Shellfish and Their Allergies

There are several types of shellfish. Each type contains different proteins. Depending on the type of protein identified by your body as an allergen, you can end up with an allergy.

Types of shellfish include:

  • Crustaceans include crabs, lobster, crayfish, shrimp, and prawns;
  • Mollusks include squid, snails, clams, oysters, mussels, octopus, abalone, and scallops.

Some people are only allergic to one type of shellfish but can consume others without any problem. Research also shows that most people with shellfish sensitivity seem to be allergic to crustaceans, with shrimp being the most common shellfish allergen for children and adults. The reactions to these foods tend to be more severe. People with one shellfish allergy must stay away from all shellfish to prevent complications.

Living With Shellfish Allergy

Allergic reactions to shellfish can be unpredictable. Even limited amounts of shellfish can cause critical and potentially life-threatening complications, such as anaphylaxis. If you have a shellfish allergy, doctors recommend keeping an epinephrine injection device with you at all times as it is the first-line treatment against the allergy.

It is essential to understand that a shellfish allergy is different from an allergy to fish. Your allergy to shellfish does not mean you have to avoid fish, but care is needed to prevent cross-contact between fish and shellfish.

Avoiding Shellfish

To prevent a reaction and its complications, it is essential to avoid all shellfish and shellfish products. You must read food levels and ask questions regarding ingredients before eating a food you have not prepared yourself or know anything about to prevent shellfish intake.

It is observed that people allergic to one group of shellfish are allergic to other types too. Doctors recommend avoiding all kinds of shellfish when you do not know about their reaction. If you are allergic to a specific variety of shellfish but want to try out the other type, first consult your doctor to learn about allergy testing.

How to avoid shellfish allergy

  • Stay away from seafood restaurants where there is a high risk of food cross-contact.
  • Maintain caution when eating out to ensure the pan, oil, or utensils used for shellfish are not used to prepare other foods.
  • Avoid touching shellfish or going to fish markets.
  • Stay away from places where shellfish are cooked as shellfish protein could be in the steam.
  • Check the ingredient list before buying a product to see if it contains any shellfish.

Doctors recommend avoiding foods that contain shellfish or traces of these ingredients, such as:

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

Your doctor may also advise you to avoid mollusks or ingredients including:

  • Abalone;
  • Clams (cherrystone, geoduck, littleneck, Pismo, quahog);
  • Cockle;
  • Cuttlefish;
  • Limpet (lapas, opihi);
  • Mussels;
  • Octopus;
  • Oysters;
  • Periwinkle;
  • Sea cucumber;
  • Sea urchin;
  • Scallops;
  • Snails (escargot);
  • Squid (calamari);
  • Whelk (Turban shell).

It is important to note that sometimes mollusks are not fully disclosed on products labels. You must be very careful before buying products that contain kinds of seafood or traces of these products.

Shellfish is sometimes also found in the following:

  • Bouillabaisse;
  • Cuttlefish ink;
  • Glucosamine;
  • Fish stock;
  • Seafood flavorings such as crab or clam extract;
  • Fish stock or fish sauce made from krill;
  • Surimi.

Carrageenan or Iodine – Are They Too Shellfish?

Carrageenan or Irish moss is not shellfish. It is a red marine algae used as an emulsifier, stabilizer, and thickener in many products like dairy foods. It is safe for most people with food allergies.

Shellfish allergy is often confused with iodine allergy as shellfish are known to contain the element iodine. However, it is necessary to note that iodine is not the agent that triggers the allergic reaction. The major allergen in shellfish is a muscle protein called tropomyosin that leads to symptoms of allergy. If you have a shellfish allergy, cross-reactions with iodine or radiocontrast material do are not causes for concern.

How Shellfish Allergy Is Diagnosed

The doctor will ask about your symptoms and perform a physical exam to check for rashes and other evidence of allergic reaction.

The following tests are recommended to know more about your condition:

  • Skin test – The skin is pricked and exposed to small amounts of the proteins found in shellfish. If you are allergic, there will be a raised bump or hive at the test site on your skin.
  • Blood test – Called an allergen-specific IgE antibody test or radioallergosorbent (RAST) test, it measures the immune system’s response to shellfish proteins. It checks for the number of antibodies, known as immunoglobulin E (IgE) antibodies, in the bloodstream.

A history of allergic reaction shortly after exposure to shellfish is a clear sign of shellfish allergy, but testing is the only way to diagnose the source of symptoms and rule out other factors such as food positioning.

How to Treat Shellfish Allergy

You must seek immediate medical assistance if you suspect a shellfish allergy before it turns serious. The doctor will recommend diagnostic testing to confirm the presence of an allergy to ensure prevention from any unexpected outcome.

Epinephrine is the first-line treatment for shellfish sensitivity. Doctors prescribe an epinephrine auto-injector for people with allergies to carry with them all the time. In cases of exposure or a severe reaction, even second matters. Epinephrine must be administered as soon as possible to prevent the symptoms from worsening and becoming potentially dangerous.

Other medications such as antihistamines and corticosteroids are also recommended for treating mild symptoms of food allergy, but there is no substitute for epinephrine. It is the only medication that can reverse the life-threatening symptoms of anaphylaxis.

The best way to manage and treat shellfish allergy symptoms is by avoiding them altogether. Carefully go through the ingredient labels of the food products and learn other names for the items you need to avoid to ensure you do not eat them. Consult your allergist to know more about food choices and alternatives to understand what foodstuffs contain traces of shellfish and how to avoid them.

Do not ignore your shellfish allergy, even if they are mild, as they can turn serious if left untreated. The allergy doctors at the Century Medical and Dental Center in NYC help you understand what causes sudden shellfish allergy and what you can do to prevent worsening it. Using the latest technology and medical research, experienced and board-certified doctors come up with effective treatments and cure that not only relieve the allergy but also help you avoid painful reactions in the future.

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