Solve Your Shellfish Allergies!

Shellfish Allergy Testing & Treatment

Get personalized testing and treatment for your shellfish allergies. Dr. Sonia Cajigal is a board-certified allergist that has helped countless patients navigate shellfish allergies in the greater St. Louis area. Schedule your visit today if you have shellfish allergy symptoms!

“Dr. Cajigal was friendly, professional, and informative. She took the time to explain the tests and what was going on with my allergies. She is so knowledgeable and really cared about how I was feeling. I would highly recommend this practice if you suffer from allergies and asthma.”

– Sue D, July 2020

Shellfish Allergy Doctor Sonia Cajigal of St. Louis Family Allergy in St. Louis, Missouri
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About Shellfish Allergies

What Causes Shellfish Allergy

Shellfish Allergy Symptoms
Shellfish Allergy Testing
Shellfish Allergy Treatment

What Causes Shellfish Allergy

Shellfish allergy occurs when your body produces an immunological response to tropomyosin and other muscle proteins found in shellfish. Crustacea are the most common cause of shellfish reactions, including shrimp, crab, and lobster. Mollusks can also trigger shellfish allergies, but are less prevalent than crustacean reactions. Unlike most other allergies, shellfish allergies tend to develop in adulthood and typically last for life.

See a Shellfish Allergy Specialist

in St. Louis, Missouri

Common shellfish allergy causes: crustaceans, imitation crab, mollusks

Shellfish Allergy List

Many foods and ingredients contain shellfish protein, but it’s important to note the difference between a shellfish allergy and a seafood allergy. You can be allergic to shellfish without being allergic to other seafood in which shellfish proteins are absent, such as salmon, trout, halibut, cod, or tuna.

Here is a shellfish allergy list of common seafood that may trigger symptoms if you have a shellfish allergy: 


  • Lobster
  • Crab
  • Imitation Crab
  • Shrimp
  • Prawns



  • Calamari
  • Squid
  • Clams
  • Scallops
  • Oysters
  • Mussels
  • Snails


Shellfish Products

  • Oyster Sauce
  • Fish Oil Supplements (may contain trace amounts of shellfish proteins)

Shellfish Allergy Symptoms

Shellfish allergy symptoms usually appear within minutes of ingestion, but symptoms may also appear a few hours later. Shellfish allergy symptoms include:
  • Hives
  • Angioedema (swelling under the skin)
  • Gastrointestinal symptoms, such as nausea, vomiting, cramping, or diarrhea
  • Lightheadedness or fainting
  • Anaphylaxis
It’s possible for individuals with shellfish allergies to have an asthma reaction when exposed to certain triggers, even if they haven’t consumed shellfish directly. For example, vapors from shellfish being cooked or processed may induce asthma. It’s also possible to have a shellfish allergy that’s only triggered by intense exertion following ingestion. Under most circumstances, these individuals are able to eat shellfish without any reaction, and are appropriately surprised when they react to shellfish for the first time.
Shellfish Allergy Testing

in St. Louis, Missouri

Woman reacting to shellfish allergy symptoms scratching rash on her neck

Shellfish Allergy Testing in St. Louis

The first step to overcoming shellfish allergies is to receive a proper diagnosis from a specialist. Dr. Cajigal will help you identify exactly what you’re allergic to using a combination of your medical history and a combination of shellfish allergy tests outlined below.

Shellfish Allergy Skin Test

Dr. Cajigal may suggest a skin-prick test, where small volumes of shellfish allergens (and controls) are placed on your skin and pricked with a sterile needle. After 20 minutes, the skin is re-examined for any bumps indicating an allergic reaction.

Blood Test For Shellfish Allergy

A blood test can measure the amount of antibody circulating in the blood in reaction to the specific food allergen of interest. This confirmatory test is often used to rule out a suspected allergen if skin testing shows no response.

Elimination Diet

You may be asked to temporarily eliminate shellfish or other specific foods from your diet for 2 to 4 weeks. If your allergic symptoms disappear during this time, it is likely that one or more of the eliminated foods was the allergen.

Food Challenge

A food challenge involves consuming a small amount of the suspected food allergen in a supervised, medical setting. This can help confirm an allergy or verify if you have outgrown one.

Shellfish Allergy Treatment

in St. Louis, Missouri

Girl using EpiPen to treat severe shellfish allergy reaction

Shellfish Allergy Treatment in St. Louis

There are steps you can take to minimize allergen exposure and effectively manage shellfish allergy reactions.


The most important part of managing shellfish allergies is to avoid ingestion and other forms of exposure. Be sure to read food labels and always ask about ingredients when eating at restaurants or when eating foods prepared by family or friends.

Shellfish Allergy Medications

Antihistamines can help relieve symptoms when shellfish reactions are mild. Be sure to discuss any medications for shellfish allergy treatment with Dr. Cajigal before using them.

Emergency Action Plan

When you have a shellfish allergy, it’s not always possible to control your environment, so it’s important to carry medications in case of a reaction. You should also carry an EpiPen (autoinjectable epinephrine) with you at all times in the event of a severe shellfish reaction. With your children, it’s also important to make adults in their lives aware of their allergies and what to do in case of mild and severe reactions. This may include teachers, coaches, babysitters, etc. There’s more you can do to find relief from shellfish allergies. Visit us at St. Louis Family Allergy to get a personalized shellfish allergy treatment plan that accounts for your unique symptoms and the unique aspects of your daily life.


[1] American College of Allergy, Asthma & Immunology: [2] Asthma and Allergy Foundation of America:
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Visit Allergist Dr. Sonia Cajigal of St. Louis Family Allergy in St. Louis, Missouri

Shellfish Allergist Dr. Sonia Cajigal

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St. Louis Family Allergy Google review score badge
"Dr. Cajigal was friendly, professional, and informative. She took the time to explain the tests and what was going on with my allergies. She is so knowledgeable and really cared about how I was feeling. I would highly recommend this practice if you suffer from allergies and asthma."

- Sue D, July 2020

“Dr Cajigal is a great listener. She trusts her patients instead of treating them as if they are not the experts of their own bodies. I really appreciate that (many doctors do not have that quality). She also immediately treats the symptoms instead of waiting to see if things clear. I use her for my children and myself. We have never left her office feeling as if it was a waste of time.”

– Stephanie, August 2020

"Great Allergist!"

- Ann H, December 2018

"She is the best."

- Stephen W, June 2020

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