Food Allergy vs Food Intolerance in Children

“My child gets a tummy ache after eating certain foods. Is it an allergy?”

“Does every reaction to food mean my child has a food allergy?”

Not necessarily.

Food allergy and food intolerance are different conditions. Knowing the difference can help parents understand when a reaction may require urgent attention and when further assessment is needed.

What Is a Food Allergy?

A food allergy involves the immune system reacting to a particular food protein.

Common food allergens in children include:

Common Allergens

Cow's milk
Egg
Peanut
Tree nuts

Other Common Allergens

Soy
Wheat
Fish
Shellfish

Symptoms may include:

Skin

Hives or an itchy rash

Swelling

Swelling of the lips, face or eyes

Digestive

Vomiting, abdominal pain or diarrhoea

Breathing

Coughing, wheezing or breathing difficulty

Severe Reaction

Dizziness, lethargy or collapse

Symptoms can occur within minutes to a few hours, depending on the type of food allergy.

What Is Food Intolerance?

Food intolerance does not involve the immune system in the same way as a food allergy.

It may occur when the body has difficulty digesting or processing a particular food or food component.

Examples include:

Lactose intolerance – difficulty digesting lactose, the sugar found in milk
Intolerance to certain fermentable carbohydrates
Symptoms related to naturally occurring substances or food additives in some individuals

Symptoms are more commonly digestive and may include:

Bloating
Abdominal discomfort
Excessive gas
Diarrhoea
Nausea

Food Allergy and Food Intolerance Are Not the Same

Food allergy involves the immune system, while food intolerance generally does not.

The symptoms can sometimes overlap, which is why the pattern of symptoms and the child's overall history are important.

“My child gets diarrhoea after drinking milk. Is it a milk allergy?”

Not necessarily.

Lactose intolerance can cause bloating, gas and diarrhoea after consuming lactose.

Cow's milk protein allergy, on the other hand, is an immune reaction to milk proteins and may cause symptoms involving the skin, gastrointestinal tract or respiratory system.

Milk allergy ≠ lactose intolerance.

The two conditions require different approaches, so removing all dairy products without understanding the cause may not be necessary.

“Can food allergy cause tummy symptoms?”

Yes.

Food allergy can cause vomiting, abdominal pain or diarrhoea, sometimes together with skin or respiratory symptoms.

However, digestive symptoms alone are not enough to confirm a food allergy. Other conditions can cause similar symptoms, so the child's overall history and pattern of reactions are important.

Can My Child Outgrow a Food Allergy?

Some children do.

The likelihood depends on the specific food, the type and severity of the allergy, and the child's individual history.

A paediatrician or allergy specialist can advise whether and when food reintroduction may be appropriate.

Do not try to reintroduce a food at home if your child has previously had a severe allergic reaction.

Should I Remove the Food From My Child's Diet?

Do not unnecessarily eliminate foods without medical advice.

Unnecessary elimination diets can lead to nutritional deficiencies, restricted diets and anxiety around eating, particularly in growing children.

If a food allergy is suspected, the doctor may assess the reaction history and determine whether allergy testing, a supervised elimination and reintroduction, or a medically supervised food challenge is appropriate.

When Should Parents Arrange a Paediatric Assessment?

Consider an assessment if:

Symptoms repeatedly occur after eating a particular food
Your child develops hives or swelling after eating
There is recurrent vomiting or diarrhoea associated with specific foods
Your child has eczema together with suspected food reactions
Your child's diet has become increasingly restricted
There are concerns about nutrition or growth

Seek Urgent Medical Attention If

Your child has difficulty breathing or wheezing
The lips, tongue or throat suddenly swell
Your child becomes pale, floppy, unusually sleepy or collapses
Your child develops symptoms involving more than one body system, particularly soon after eating a suspected allergen

A severe allergic reaction can develop quickly and requires urgent medical attention.

Frequently Asked Questions

What is the difference between food allergy and food intolerance?

Food allergy involves the immune system reacting to a food protein, while food intolerance generally does not involve the immune system and is often related to difficulty digesting or processing a food component.

Can food allergy cause diarrhoea or stomach pain?

Yes. Food allergy can cause vomiting, abdominal pain or diarrhoea, sometimes together with skin or respiratory symptoms. However, digestive symptoms alone do not confirm a food allergy.

Is lactose intolerance the same as a milk allergy?

No. Lactose intolerance involves difficulty digesting lactose, while cow's milk protein allergy is an immune reaction to proteins in cow's milk.

Should I stop giving my child a food if I suspect an allergy?

If your child develops a concerning reaction, seek medical advice. Avoid unnecessary long-term elimination diets without professional guidance, as they may affect nutrition and growth.

When should my child be assessed for a food allergy?

Assessment may be considered when reactions repeatedly occur after a particular food, especially when there are symptoms such as hives, swelling, vomiting, breathing symptoms or concerns about nutrition and growth.

Take-Home Message

Food allergy involves the immune system; food intolerance generally does not.

Not every tummy symptom after eating is a food allergy. A careful history and appropriate assessment can help determine whether your child needs dietary changes, allergy testing or further evaluation.

Concerned About Your Child's Food Reaction?

If your child repeatedly develops digestive, skin or other symptoms after eating certain foods, a paediatric assessment can help identify the possible cause.

Southern Child Specialist Clinic in Johor Bahru provides paediatric assessment for suspected food allergies, food reactions and related nutrition concerns.

Book a Paediatric Consultation

Evidence & Guidelines

This information is based on:

EAACI Guidelines on Food Allergy
WAO DRACMA Guidelines – Diagnosis and Management of Food Allergy
NICE Guideline – Food Allergy in Children and Young People
ESPGHAN guidance on food allergy and nutritional management