Allergies

What is a food allergy?

A food allergy is the response of the body’s immune system to normally harmless proteins found in foods.

There are two types of allergy:

• IgE-mediated (immediate) allergies
• Non IgE-mediated (delayed) allergies.

IgE stands for ‘immunoglobulin E’ – which is a type of antibody in your immune system.

With IgE-mediated allergy, the proteins in foods bind to the IgE antibodies on the mast cells. This makes the cells react and release chemicals for example histamine and this is associated with some of the symptoms experienced when having an allergic reaction.

Non IgE-mediated allergies still involve the immune system but different components of it.

What about allergy tests?

We hear a lot about food allergy testing. The only validated tests available are blood tests and skin prick tests which are able to detect if there is an IgE-mediated allergy.

Even then, these tests are not always accurate and need to be interpreted with a thorough clinical and allergy-focused history. Non IgE-mediated allergies or 'delayed' allergies can only be diagnosed through dietary exclusion and re-introduction.

What are the symptoms of  a food allergy?

Symptoms of an allergy can vary greatly from mild to severe.

Some typical IgE-mediated symptoms include:

• Skin symptoms- e.g. hives or urticaria (raised red bumps, often itchy), redness, itching, swelling e.g. of the lips, eyes and face.

• Respiratory symptoms - breathing difficulties, wheeze, worsening of asthma

• Gut symptoms - acute diarrhoea, vomiting

These symptoms typically occur within minutes after eating the food but can take up to 2 hours.

Some typical Non IgE-mediated symptoms include:

• Skin- worsening of eczema which might not respond to treatment, non descript rashes which come and go.

• Gut symptoms- vomiting, reflux, diarrhoea, mucous or blood in stools, excessive wind, abdominal pain constipation.

These symptoms occur from 2 hours and up to 72 hours after eating, which is why they can be more difficult to diagnose.

Why See a Paediatric Dietitian for Food Allergies?

Are you unsure if your child has an allergy? Are they having symptoms but you just can't get to the bottom of what it might be?

I can help at all stages of managing food allergies. This might be helping to diagnose allergies (immediate and delayed types of allergies), helping with dietary exclusions and making sure your little one is getting all the nutrients they need.

This might be for breastfeeding mums, infants who are weaning or older children. I can also support with safely reintroducing allergens back in your childs diet and giving you the confidence you need to start making those first steps.

Your child might not be showing typical allergic symptoms, but you know that there are some ongoing gut issues, which you feel might be related to their diet. It might be that they have a food intolerance.

I can help to diagnose and treat these by taking an in depth diet and symptom history, identifying possible triggers and giving a clear plan to follow. This might involve tweaking your child's diet or trialling some dietary exclusions.

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