Food Allergy - Is your baby at risk?
Food allergy is a huge problem among Australian children and is certainly something that most parents worry about. Fortunately there is a lot of research happening in this space. Here is a wrap up of what I learned at a recent medical update on food allergy and current thoughts on prevention.
How common is food allergy?
Currently around 10% of all Australian children under the age of 12 months will have a food allergy, this decreases to around 3% of 4 year olds as many children will outgrow their allergies. The prevalence of food allergy in children has continued to increase over recent decades.
There is an enormous amount of research happening around the world to try to figure out why food allergies are on the increase. A number of theories are under investigation and include:
Vitamin D deficiency in pregnancy – there seems to be a link between vitamin D deficiency in pregnant mothers and subsequent development of food allergy in children. This is an association only and certainly does not mean that all babies born to mothers with vitamin D deficiency will develop allergy. If you are currently pregnant or planning on becoming pregnant it might be wise to have your vitamin D levels checked.
Hygiene theory – you may have heard of the "microbiome" which refers to a person's bacterial make up. Did you know that we all have thousands of "good bacteria" colonising our systems? It seems that there is a link between the microbiome and the risk of developing a food allergy. Exposing infants to germs by having pets or allowing outside play in the dirt seems to help reduce the risk of food allergy. Conversely, things like early antibiotic use and caesarean delivery promote a more sterile environment and have been linked to an increased risk.
Delayed introduction of solids – Until recently we thought that delaying the introduction of allergenic foods would help to prevent food allergy. It now seems that we were wrong. Current guidelines now recommend an earlier introduction of allergenic foods, more on this later.
What are the different types of food allergy?
Food allergy in children can vary from mild skin reactions through to severe, life threatening anaphylaxis.
Allergic reactions to food are considered in two different groups. IgE mediated and non IgE mediated.
This classification relates to the underlying pathological process which causes the reaction.
The distinction is important as it changes the diagnosis and management options.
IgE Mediated Food Allergy
This is the type we worry most about as parents.
Let me try to explain how this works. IgE is a type of antibody that is produced by the body in response to a "threat." In food allergy the immune system sees a particular food as a "threat" and over reacts with an immune response causing symptoms of allergy.
The most common foods that cause this type of allergy are nuts, soy, seafood, eggs, wheat and dairy. In many cases children will grow out of allergies to these foods, however peanut allergy is likely to persist through life.
Symptoms of IgE mediated food allergy include hives, swelling around the eyes or mouth, coughing and difficulty breathing. Generally these symptoms occur within 1-2 hours of exposure.
Diagnosis can be aided by skin prick testing, or a blood test which can help to confirm the presence of an allergy. Sometimes an oral food challenge may be required to confirm the diagnosis. This is a high risk test which would always be done in a hospital under specialist supervision.
Management of this type of food allergy includes strict avoidance of the implicated food. If there is an accidental exposure then emergency management including adrenaline (epipen) and antihistamine may be required.
Non IgE Mediated Food Allergy
The other type of food allergies (Non IgE mediated) have a different mechanism and often present with symptoms related to the skin or gastrointestinal tract. There are many different conditions within this category including:
Cows Milk Protein Allergy
Food Protein Induced Enterocolitis Syndrome (FPIES)
Food protein induced proctocolitis.
Eczema (50% associated with food allergy)
With the exception of FPIES (Food Protein Induced Enterocolitis Syndrome) which is a rare condition, these allergies are generally not life threatening.
I see many young babies with Cows Milk Protein Allergy who present with poor weight gain, irritability, eczema and sometimes blood or mucous in the stool. There is no test for this type of allergy and diagnosis relies on removing dairy from the diet and monitoring the child. This should only be considered after talking to your doctor as removing food groups from the diet can have nutritional consequences. More on this in an upcoming blog piece.
It is also important to note that intolerance to food does not equal a food allergy. Many people will experience abdominal pain and bloating, and a change in bowel habit associated with certain foods however this is not an allergic process. Confusing I know!
Can I reduce the risk of my child developing a food allergy?
The good news is that there is some promising results from the studies that are currently being done to learn more about food allergy.
Did you know that initial exposure to food products via the skin rather than the mouth can increase the risk of developing an allergy to that food? Products such as coconut oil, almond oil and oatmeal based moisturisers are quite popular at the moment but could be increasing the risk of food allergy. Talk to your doctor about the safest products to use on your child's skin.
What about starting solids? Well, we now know that there is an optimal period from 4 to 12 months for introducing high risk foods to babies to help prevent allergies.
We advise that you should start feeding your baby solids between 4 and 6 months. The first foods introduced sho
uld be things such as iron fortified cereals, fruit, vegetables and meat based products. Higher risk foods including egg, dairy, fish, wheat and nut products should be introduced gradually but certainly before the age of 12 months. Infants with a strong family history of severe allergic disease should discuss this with their doctor prior to commencing solids.
The Australasian Society of clinical immunology and allergy has produced an informative handout on starting solids which can be accessed by clicking here. (ASCIA)
There is also some promising research being conducted in Australia looking at trying to desensitise individuals who are allergic to food, in particular nuts. The results are encouraging, watch this space ……
So what does this mean for my baby or young child?
So, the take home messages from this blog include:
- minimise unnecessary antibiotics and think about allowing some gentle exposure to germs through pets and outdoor play.
- start solids between 4-6 months and gradually introduce higher risk foods before 12 months
- avoid moisturisers and skin products which are food based - save these things for eating!
- make sure you talk to your doctor if you think your baby or child has a food allergy.
Although there is still so much that we do not yet understand about food allergy it is exciting to learn of new developments and promising treatments. Stay tuned.