Food allergies, what parents need to know

Food allergies can cause a huge amount of confusion and worry for parents. Here dietitian Sarah Keogh answers some of the common questions she has been asked by parents.

What are the different types of food allergy?

There are two main types of food allergy: immediate and delayed.

Immediate allergy causes symptoms to show up very soon – less than 15 minutes after a food is eaten. Sometimes symptoms of immediate allergies can take up to 2 hours to appear, but this is rare. Symptoms of immediate allergy include sneezing, coughing, wheeze, itchy eyes, hives or rash, and swelling. There can sometimes also be stomach pain or vomiting but this is much less common.

Delayed food allergy can take between 2 and 24 hours to show symptoms. This type of allergy is more common in children who are allergic to cow’s milk. They can react to milk, baby formula made from milk, cheese, and yoghurt. This type of allergy usually causes tummy symptoms like diarrhoea, vomiting, blood in the stools, reflux and bloating.

How common are food allergies?

Food allergies are fairly common and affect 5-6% of young children in Ireland. The most common food allergies are milk, egg, nuts and fish and these account for around 90% of food allergies seen in Ireland.

Food allergies tend to become less common in adulthood as many children will grow out of their food allergy. This is more likely if the child has a milk or egg allergy. Children are less likely to grow out of peanut, tree nut, fish or shellfish allergies.

Pregnancy & Allergies: There is no need for a pregnant woman to avoid allergenic (allergy-causing) foods like peanuts or nuts during pregnancy unless she is allergic herself. Although there have been lots of studies on eating or avoiding different foods during pregnancy to prevent allergies, there no clear differences and the best advice is to eat a balanced, healthy diet with lots of variety.

Weaning and Allergies: There are lots of studies looking at how to prevent food allergies. Overall, there does not seem to be any way to completely prevent food allergy. However, giving babies lots of different foods from an early age may help to reduce their chances of developing a food allergy.

Introducing foods like well-cooked egg, milk, nuts, peanuts (as a smooth peanut butter) early is advised to help reduce risk of allergies. When a baby is weaning, these foods can be introduced from 6 months and ideally before 1 year. There does not seem to be any benefit in delaying these foods – early introduction seems to have the best benefit.

Peanut (as smooth peanut butter) should be introduced before a baby is one year old. Just remember that peanut butter is quite sticky and may be a choking risk if a baby is given a whole spoonful to try. Spread some smooth peanut butter on some toast if your baby is ready for finger foods or put a little on your finger for them to taste. Smooth peanut butter can also be mixed into cereals or vegetable purees.

Eczema and Allergies: Babies with eczema are more likely to develop a food allergy. It is much more often the case that the allergy is caused by the eczema rather than the other way around.

It is not recommended that babies with eczema have extensive allergy testing to see if a food allergy is causing the eczema. A consultation with a registered dietitian can help to identify a potential food and that specific food should be tested rather than a whole range of foods. This helps to reduce the number of foods babies are avoiding and helps maintain a good, balanced, diet for growth and overall health. The focus for treatment for eczema is with emollients and topical steroids as recommended by your doctor rather than a focus on avoiding foods. It is best that babies with eczema have their skin in good condition before weaning so do talk to your GP about this.

Allergenic foods should be included in the diet of babies with eczema as they are weaning just like any other baby. The one exception is peanut – babies with severe eczema should be tested for peanut allergy before introducing peanut. Speak to your GP about testing.

If there is a strong history of severe eczema or allergy in the family do speak to your GP before weaning as there may be some restrictions.

What if I think my child has a food allergy?

If you think your baby or child has a food allergy it is important to see your GP and get properly checked out. Alot of commerically available food sensitivity tests are unreliable and cannot diagnose or rule out a food allergy. If your child does have a food allergy you need to see a registered dietitian for advice on how to manage changes in your child’s diet. This is especially important if whole food groups like dairy must be avoided as this can affect children’s normal growth and development.

Check out our food allergen section for more information.