I'm not crabby, it's just a crustaceans allergy.

There are so many different allergens that it can sometimes be hard to keep up. A crustaceans allergy or shellfish allergy is one that not many people talk about even though it is one of the most common allergies affecting around 2% of the population. 

Like many allergies, the level of severity may differ from person to person. Some people may be able to eat certain types of crustaceans or shellfish, while others may have to abstain entirely. 


Symptoms of this type of allergy are similar to the many food allergies out there, they can include but are not limited to:

  • Hives, itching or eczema 

  • Swelling of the lips, face, tongue and throat, or other parts of the body

  • Wheezing, nasal congestion or trouble breathing

  • Abdominal pain, diarrhoea, nausea or vomiting

  • Dizziness, lightheadedness or fainting

These symptoms can be severe or mild depending on the individual as well as how much has been ingested or if contact has been made. If you find you are severely allergic and go into anaphylaxis shock immediate medical attention must be sought out. Those who are aware of their allergy may carry around EpiPens or specific medication to help with their reactions. 

What causes this reaction?

Your body is reacting to the protein found in shellfish. It mistakes this protein as harmful and reacts by releasing antibodies to remove the protein. This reaction causes the symptoms listed above.

There are many types of shellfish and you may find you are allergic to one or both:

Crabs, lobster, crayfish, shrimp and prawns.

You are more at risk of developing this allergy if someone in your family suffers from it. Although, a crustaceans allergy is more common in adults and can develop later in life. If you suffer from asthma or any other food allergy you may find your reactions more severe. 

The best remedy for this type of allergy is avoidance. Making sure to keep your diet free of any foods which could contain or may have been in contact with shellfish is the safest way to avoid an allergic reaction. 

Are you worried?

If you suffer from any allergy eating out can be a constant worry. All restaurants and caterers should specify what potential allergens are in their foods and recipes, and hygiene standards should remain high. If you have any questions about ingredients you should always speak with your server or the owner of the restaurant. Never be scared to speak up about something which could cause you harm. If you notice the restaurant isn’t clear on their allergen labelling, you could always recommend they use Allergen Checker’s 7 day free trial for a clean and simple solution. 

The information provided in this blog is purely informational. Please speak to your GP for further information on any concerns you have regarding crustaceans allergies. Sources for information are: