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Real members of MyFoodAllergyTeam have posted questions and answers that support our community guidelines, and should not be taken as medical advice. Looking for the latest medically reviewed content by doctors and experts? Visit our resource section.

Can a food intolerance turn into an allergy?

A MyFoodAllergyTeam Member asked a question 💭
Quebec, QC

I have very severe intolerance to seafood which give me very intense gastrointestinal symptômes and migraines. I almost passed out once like 4 to 6 hours after eating shellfish. The other people I was with were fine. And just the smell of it gives me a wicked headache.

May 3
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A MyFoodAllergyTeam Member

I used to carry an auto injector epiphene around before. I will definately ask for another one just in case but will need to do the allergy test again since I moved out of the province I think. 🙃

May 4
MyFoodAllergyTeam

Can a food intolerance turn into a food allergy? Based on what's been shared here, it's worth pausing on whether this is actually an intolerance or already an allergy — because some of these symptoms are raising flags.

Here's the key difference:

- Food intolerance affects mainly the digestive system and is not Show Full Answer

Can a food intolerance turn into a food allergy? Based on what's been shared here, it's worth pausing on whether this is actually an intolerance or already an allergy — because some of these symptoms are raising flags.

Here's the key difference:

- Food intolerance affects mainly the digestive system and is not life-threatening
- Food allergies involve an immune system reaction and can affect the whole body — and can be fatal The nearly passing out episode 4–6 hours after eating shellfish is particularly worth noting. Delayed reactions to shellfish *can* occur, and dizziness or fainting can be symptoms of a serious allergic reaction, not just an intolerance.

Reacting to the smell alone is also a sign that points more toward an allergy than an intolerance. This is really important: even if past reactions have felt manageable, allergic reactions to shellfish can become more severe over time — including triggering anaphylaxis, which is a life-threatening whole-body reaction.

Seeing a doctor or allergist as soon as possible would be strongly advisable here. They can properly test whether this is an allergy, and if so, may recommend carrying an epinephrine auto-injector (like an EpiPen) for emergencies.

In the meantime, avoiding shellfish entirely — including anything prepared near shellfish — is the safest approach.

May 3

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