Food allergy or food intolerance?

• rash
• wheezing
• itching
• severe gut symptoms
• very rarely, sudden collapse
• there may also be swelling of the throat and mouth, which can cause difficulty swallowing or speaking

Allergic symptoms – which include asthma and eczema – tend to occur soon after your child eats a trigger food, often within minutes. The symptoms can be extreme and even life-threatening, and it may only take a tiny amount of the problem food to set off a reaction.

Common allergens among children are cow’s milk and eggs.

Symptoms of a food intolerance

The signs of intolerance are more variable than allergic symptoms. They can include:

• fatigue
• bloating
• irritable bowel
• joint pains
• rashes
• nettle rash
• eczema
• migraine

Intolerance symptoms tend not to develop as quickly after your child eats a trigger food. It can be hard to identify an intolerance, as the symptoms may build up slowly over the course of several days or weeks, and can be less obvious in a young baby or child who can’t tell you what’s wrong.

Lactose intolerance occurs in less than 2% of infants. Lactose is present in milk (including formula and breastmilk), and, to a lesser degree, in yoghurts and soft cheeses. The main signs of lactose intolerance are diarrhoea and stomach pain. Gluten intolerance, or coeliac disease, is triggered by products containing wheat, rye and barley. Signs include diarrhoea, wind, weight loss, mouth ulcers and muscle aches and pains. About one in 100 people in the UK have coeliac disease, but many more live with the condition undiagnosed.

Diagnosing allergies and intolerances

If you’re concerned that your child has an allergy or food intolerance, the first port of call is your doctor. It may be helpful to keep a two-week diary of all foods consumed by your child and his symptoms. If his symptoms are severe or your child loses consciousness, call an ambulance or go to your nearest A&E.

Allergies can be diagnosed by medical tests and on the basis of family history. Intolerances are difficult to diagnose as tests tend to be unreliable. If it isn’t clear which is the problem food, an elimination diet may be recommended by an appropriately qualified health care professional such as a paediatric dietitian, where you cut out all suspect foods and then reintroduce them gradually, one by one, to monitor your child’s symptoms.

Don’t try to self-diagnose your child’s allergy or intolerance, as cutting out foods without medical guidance may lead to nutritional deficiencies, especially if you eliminate a key food group like dairy or wheat. Your doctor will also want to rule out other causes of your child’s symptoms, such as inflammatory bowel disease or gastrointestinal obstructions.

If family history suggests your child might be at risk of allergies – for example if you or your partner has asthma, eczema, hay fever or other allergies – it’s especially important to try to breastfeed exclusively until six months and not introduce solids before this point to reduce the likelihood of allergies.