How can a shellfish allergy be diagnosed?

You should talk to your doctor about any symptoms that you have and when they happen. Keep track of what you ate up to 6 – 8 hours before any symptoms occurred. Your doctor might come up with a list of possible foods that might be causing you problems, and might ask you for permission for additional tests. There are 3 main tests – the elimination dietary challenge test, the RAST (radioallergosorbent test), and a skin test.

Out of the three different types of test, the elimination dietary challenge test is the most reliable way of finding out whether you are allergic to seafood. Your doctor will ask you not to eat any shellfish or shellfish containing foods for a while, and will ask you to see if your symptoms disappear. You will then be asked to resume eating shellfish, in order to determine if your symptoms start again. If your symptoms vanished in the period of time when you weren't eating shellfish and resumed when you resumed eating shellfish, a shellfish allergy is likely. Elimination dietary challenges should be done in consultation with your doctor or a dietician.

A RAST (radioallergosorbent test) is done by taking a blood sample and trying to react various allergens with the chemicals (in particular, IgE) in your blood. It is done in the lab, and is quite reliable too. A skin prick test is less reliable and accurate than a RAST, and involves introducing small amounts of allergen to the skin to see if a reaction develops. If you are allergic to shellfish, you might see a “wheal and flare” - an irregular, blanched area of skin surrounded by a reddened area of inflammation.

Shellfish Allergy Guide Index:

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• What is a shellfish allergy?
• What are the signs and symptoms of a shellfish allergy?

• How can a shellfish allergy be diagnosed?
• How can a shellfish allergy be managed?

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