Allergic March by Dr Vivian Chen

Great blog by Dr Vivian Chen!

Have you heard of the ‘allergic/atopic march?’ – if not, read on….

Genes can predispose us to develop allergies – and that’s why it often runs in families… but the same genes which cause allergies can also lead to other atopic conditions: asthma, eczema, hayfever. It often begins with eczema in infancy although eczema could also be stand alone as a skin disease.

Unfortunately, when we see kids begin to outgrow their food allergies at or before 4/5 years of age, we frequently see new conditions appearing, usually allergic rhinitis (the persistent itchy/runny nose & sniffing, with a dry cough), and asthma. Sadly, children are increasingly NOT outgrowing their food allergies (or outgrowing them later) but still accumulating the other atopic conditions like asthma and rhinitis along the way.

The ‘march’ in the name ‘allergic march’ refers to the progression of diseases which we see unfold at different ages of atopic children. It does not affect ALL food-allergic children and is not a one size fits all, but the pattern we see is this:

From age 0 – eczema – eczema may be the first sign of atopy, then…

From age 6months – 2 years – food allergy starts to appear

From age 3 years onwards – rhinitis (a persistent runny nose, sniffing, itchiness of the nose/eyes)/hayfever symptoms

From age 7 years onwards – asthma

We know egg, milk and peanut allergies are independent risk factors for development of asthma later on. And if you had BOTH peanut and egg allergy, the risk of developing asthma is even higher. There is also evidence that severity of food allergies may be correlated with the risk and severity of asthma, and sensitization to aeroallergens (e.g. grass) is also associated with the development of asthma.

This is why, despite the fact that both Sarah and Thomas have outgrown allergies (all for Sarah, some for Thomas), I carry on with the things I talked about in ‘How I helped my children grow out of their allergies’ and monitor them closely. Thomas had SEVERE allergies to milk, egg and peanuts – he also had severe eczema as an infant. So in terms of risk factors for developing asthma, he ticks ALL the boxes (sigh!) and statistically speaking he has a very high chance of developing asthma later on, and I am definitely swimming against the tide here. I may not be able to alter his genetic destiny with the dietary and lifestyle changes I’ve adopted, but I am trying my damn best! I treated asthma patients day in day out as a family physician, and I knew the impact this had on the child and family.

Aside from lifestyle measures, there is some evidence to suggest immunotherapy could alter the course of allergic diseases and prevent asthma or at least reduce its severity. Thomas is on the wait list for immunotherapy currently, because I know statistically he has a very high chance of developing asthma. In the meantime, I will just keep trying to alter his epigenetics with lifestyle measures and stay positive. I’ll keep you updated on his progress.