Do You Have a Food Allergy or Food Intolerance?

Many people experience symptoms after eating certain foods, but it can be difficult to know whether the cause is a true allergy, a food intolerance, or another gastrointestinal condition. Understanding the difference is essential for safe and effective management.

Our clinic provides specialist assessment using the ImmunoCAP ISAC® molecular allergy test, interpreted by an experienced Allergy Consultant, to help identify the cause of your symptoms and guide personalised treatment.

Video 1. How to order a home allergy testing kit

Food Allergy vs Food Intolerance

Food Allergy

A food allergy occurs when the immune system reacts to a food protein. Symptoms may be immediate (within minutes) or delayed, and can include:

• hives or swelling
• wheezing or breathing difficulty
• abdominal pain or vomiting
• anaphylaxis (in severe cases)

Because allergic reactions can be serious, the first priority is to exclude the risk of a life‑threatening reaction.

Food Intolerance

Food intolerance does not involve the immune system. It is often caused by difficulty digesting certain components of food, such as:

• lactose (due to low lactase enzyme)
• fructose
• histamine
• food additives

Symptoms are usually delayed and may include bloating, diarrhoea, abdominal discomfort, or nausea. Intolerances are diagnosed through elimination and reintroduction, not allergy testing.

Common Questions Patients Ask

After a reaction, patients often want to know:

• Was this caused by a food allergy?
• Which food triggered it?
• Could it happen again?
• What should I avoid?
• Do I need an allergy test?

Our structured ISAC questionnaire (see link at the bottom of the page, blue box) helps identify whether testing is appropriate. A consultant reviews every submission.

How the ISAC Allergy Test Works and How to order home testing kit

The ImmunoCAP ISAC® test analyses IgE antibodies to over 100 molecular allergen components using a small finger‑prick blood sample. This provides far more detail than traditional allergy tests and helps distinguish:

• true allergy vs cross‑reactivity
• risk of severe reactions vs mild oral symptoms
• heat‑stable vs heat‑labile proteins
• primary sensitisation vs pollen‑food syndrome

Your personalised report is interpreted by a specialist and delivered within two weeks.

Five Simple Steps to order home testing kit

1. Complete and submit the online questionnaire
2. Consultant review
3. If recommended, you receive an email with instructions
4. Payment (£393) and home sample kit sent
5. Results and personalised report within two weeks

Finger‑prick sampling is suitable for adults and children over 6; younger children require a healthcare‑assisted blood draw.

We give comprehensive dietary advice using the ImmunoCap ISAC® blood test

The sample collection is easy via a simple finger prick method – see our video below:
The finger prick test is not suitable for children under 6. (This needs to be done by a healthcare professional).

What Are Allergen Components?

Allergen components are individual proteins within foods, pollens, animals or venoms. Testing these provides deeper insight than whole‑extract tests. For example:

• PR‑10 proteins → usually mild, often linked to pollen‑food syndrome
• Lipid Transfer Proteins (LTPs) → heat‑stable, associated with more severe reactions
• Seed storage proteins → linked to persistent, clinically significant nut and legume allergy
• Tropomyosins → cross‑reactivity between shellfish, mites and cockroach

This level of detail helps your clinician give precise dietary advice, avoid unnecessary food restrictions, and assess your risk profile.