Food allergies

A food allergy is when the body's immune system reacts to a food, mistakenly thinking it is harmful. A mild allergic reaction might cause mild to moderate symptoms (like a rash or a sore tummy), but in some cases, it can cause a severe reaction called anaphylaxis. If a child reacts to a certain food every time it’s eaten, they likely have an allergy to that food.  

The most common food allergies are to:   

• cow’s milk
• eggs
• peanuts
• tree nuts like almonds and cashews
• soy
• fish
• shellfish
• wheat
• sesame seeds.

In New Zealand, these ingredients must be listed on food labels, even if the product only contains very small amounts of them.  

Allergies often run in families, so a baby with whānau who have allergies has a higher risk of developing food allergies. Babies with no family history can still develop food allergies.

Babies with severe eczema also have a higher chance of developing a food allergy.  

Most children grow out of their allergies, but for some this can take years. Symptoms can be mild to severe, can start rapidly, or be gradual or delayed. 

Symptoms of a reaction to food normally develop right after or within two hours of eating. It’s important to note that several foods (including citrus, tomatoes, berries, other fruits, and vegemite) when in contact with sensitive facial skin can irritate the skin, causing redness. Facial redness where food has come in contact alone is not a sign of food allergy.

Signs of a mild or moderate food allergy are:  

• red watery eyes, or puffiness around the eyes or lips
• hives or welts on the skin 
• itchy mouth or skin
• stomach cramps, diarrhoea, nausea, vomiting or colic-like symptoms.

Signs of a serious food allergy (anaphylaxis) requiring immediate medical attention are:  

• difficulty or noisy breathing or change in voice
• tongue swelling 
• coughing, wheezing, or shortness of breath 
• pale or floppy.

If your tamariki show any signs of serious food allergy (anaphylaxis) including difficulty or noisy breathing, tongue swelling, coughing/ wheezing, or going pale and floppy, act immediately by calling 111. 

Mild to moderate allergy symptoms tend to resolve within a few hours of starting. Stop giving the food you believe is causing the allergy. Seek immediate advice from PlunketLine or see your GP or nurse practitioner if you have immediate concerns.  

If you think your baby has a food allergy, avoid the suspected food and see your GP for advice.

If symptoms appear within a few minutes every time your child eats a particular food, your primary healthcare provider (GP or Nurse Practitioner) may be able to diagnose the food allergy without the need for further allergy testing.

If your child has a severe reaction or multiple food allergies, your GP may recommend your child see an allergy specialist for a skin prick or blood test.

There’s no cure for food allergies, but they can be managed.

Where a food allergy has been diagnosed, your GP or Nurse Practitioner will develop an allergy action plan with you, which will likely include avoidance of the food your baby is allergic to and steps to take if a reaction occurs.  

Severe reactions (anaphylaxis) are treated with adrenaline, using an auto-injector called an EpiPen.

In some cases, your child may see an allergy specialist who may advise gradual re-introduction of the food allergen in certain formats, or complete avoidance. Immunotherapy for food allergy in Aotearoa New Zealand is in development and may be recommended in future.

There is some research that suggests that continuing breastfeeding when introducing solids may reduce the risk of developing allergies due to the benefits on the baby’s gut.

Research shows that giving common allergy-causing foods to babies before one year of age may reduce the chances of developing an allergy to these foods. Unlike the introduction of other foods, it is important to only introduce one common allergy-causing food per meal to monitor for any reactions.

Include the following foods as age-appropriate when introducing solids to all babies before they turn one. This includes babies at higher risk of developing allergies (family history of allergies, severe eczema):

• well-cooked eggs 
• cow’s milk (in small amounts e.g., in cooking – not as a drink), cheese, yogurt
• smooth peanut butter
• finely ground peanuts or tree nuts
• wheat based foods like bread, noodles, pasta
• cooked fish or shellfish with skin and bones removed
• ground sesame seeds e.g., tahini
• soybeans, edamame (immature green soybeans), tofu

Introduce the above foods one at a time to see if a reaction occurs. If no reaction occurs, it is important you continue to offer the food regularly (around twice a week) as part of a varied diet to maintain baby’s tolerance. Trying a food once and then not continuing it in the diet may result in susceptible babies developing an allergy to that food.