By Dr. Mariam Chaalan, Le Purées GP & Co-Founder of AllerStart
When parents come into the clinic worried about food reactions, one of the first and most important conversations we have is about what kind of reaction it might be. The terms allergy, intolerance, and sensitivity are often used interchangeably, but they describe very different processes in the body. Understanding the difference helps keep children safe, reduces unnecessary anxiety, and prevents avoidable food restriction.
What Is a Food Allergy?
A food allergy occurs when the immune system mistakenly identifies a harmless food protein as a threat and mounts an immune response. This response is usually driven by IgE antibodies and tends to happen quickly after eating, often within minutes and usually within two hours.
Common symptoms can include:
- Hives, redness or swelling of the skin or lips
- Vomiting or diarrhoea
- Coughing, wheezing or difficulty breathing
- Dizziness, pallor or collapse
Because food allergies involve the immune system, reactions can sometimes escalate and become severe. This is why diagnosis, testing and management are guided by ASCIA evidence‑based recommendations, including structured action plans and, where appropriate, adrenaline prescription.
PICTURED: AllerStart Baby's First Allergens
What is a Food Intolerance?
A food intolerance is *not an immune reaction. Instead, it occurs when the body has difficulty digesting or processing certain foods or components. A common example is lactose intolerance, where there is reduced ability to break down lactose due to low levels of the enzyme lactase. Symptoms usually develop more gradually and are related to the amount eaten.
Typical symptoms may include:
- Bloating or excess wind
- Abdominal pain or cramping
- Nausea
- Diarrhoea
While intolerances can significantly affect comfort and quality of life, they do not cause anaphylaxis and are not life‑threatening.
What Is a Food Sensitivity?
Food sensitivity is a broader term used when a child reacts to a food, but the pattern doesn’t fit a classic allergy or intolerance. These reactions may involve non‑immune pathways or responses to naturally occurring food chemicals.
Examples include:
- Caffeine sensitivity
- Reactions to gluten in people without coeliac disease
- Sensitivity to food chemicals such as amines, salicylates or MSG
Sensitivities are often dose‑dependent, meaning small amounts may be tolerated, while larger amounts trigger symptoms. Reactions can be variable and harder to predict.
PICTURED: AllerStart Baby's First Allergens
How Do We Work Out What’s Going On?
Identifying the type of reaction starts with a detailed history, including what food was eaten, how much, how quickly symptoms appeared, and what those symptoms looked like.
Depending on the pattern, we may use:
- Skin prick testing or IgE blood tests to assess for true allergies
- Food and symptom diaries to identify patterns
- Structured elimination and re‑introduction plans to confirm intolerances or sensitivities
It’s important to know that not all reactions can or should be tested with blood or skin tests. Intolerances and sensitivities are diagnosed clinically, based on symptoms and response to dietary changes.
Getting the diagnosis right makes a real difference. Labelling a child with a food allergy when they have an intolerance can lead to unnecessary fear, social stress, and overly restricted diets. On the other hand, missing a true allergy can place a child at serious risk.
When we clearly understand the type of reaction, we can:
- Introduce foods safely and confidently
- Avoid unnecessary restrictions
- Support normal eating, growth and development
- Follow ASCIA‑aligned, evidence‑based guidance
If your child has had a reaction to food, or you’re feeling unsure about introducing new foods, particularly common allergens, we can guide you step‑by‑step. This is exactly the kind of support we provide families through AllerStart, helping children eat safely while giving parents clarity and confidence.
