Shellfish Allergy: Symptoms and Causes



2 min read


Shellfish Platter

Shellfish allergies are fairly common, however, not a lot of people know much about them. So, this week we’re doing a deep dive (excuse the pun) into shellfish allergies. For other allergies, check out the allergy section on the main blog page!

What is a Shellfish Allergy?

A shellfish allergy is when the body’s immune system reacts to proteins in marine animals. It is one of the most common food allergies in adults but can also affect children.

Types of Shellfish:

So, what is shellfish? There are two types of shellfish: crustaceans and molluscs. Some people are allergic to just one type of shellfish and others are allergic to both.

  1. Crustaceans are invertebrates with a segmented body. Examples of crustaceans are: crabs, lobster, shrimp, crayfish, prawns, langoustine
  2. Molluscs are soft-bodied invertebrates and only some have shells. Examples of molluscs are: squid, octopus clams, scallops, oysters, mussels, sea urchins, sea snails


A shellfish allergic reaction occurs when the body recognises the protein in shellfish as harmful. This triggers the production of antibodies. Severe reaction cases can lead to anaphylaxis which can be life-threatening.

Potential Symptoms Include: 


  • Hives (rash)
  • Tingling mouth
  • Swelling of the lips, face, tongue, or throat
  • Itching
  • Nausea
  • Vomiting
  • Abdominal pain
  • Diarrhoea


  • Difficult or noisy breathing
  • Wheezing
  • Persistent cough
  • Chest tightness
  • Hoarse voice
  • Difficulty swallowing


1. First thing’s first, Be cautious when dining out

When eating out, let a member of staff know that you have an allergy. Secondly, check that there is no cross-contamination between utensils, pans, etc. If in doubt, call ahead to check that the restaurant will be able to make provisions for you.

2. Be aware of non-food products containing shellfish derivatives

Some cosmetics, skincare products, and hair products may contain shellfish derivatives.

3. Read labels

Check ingredient labels and allergen lists on food products. You may also want to check if there is cross-contamination in the food manufacturers.

4. Be aware of ingredient changes

Lastly, sometimes even your favourite products will change their ingredients. Stay vigilant and make sure to regularly do label checks.

How Can FoodLama Help?

If you need to keep up to date with the ingredients lists of your favourite products, download FoodLama! You can input the dietary requirements for your household so that you can chill out and let FoodLama label check.


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