The ‘Allergic March’ makes me think of a parade on Memorial Day. Unfortunately, the term refers to something not so light-hearted. ‘Allergic march’ refers to the natural progression of allergic conditions from birth to adulthood. The classic allergic disorders that are seen in childhood are atopic dermatitis or eczema, food allergies, allergic rhinitis or hay fever and allergic asthma. Children that present early in life with allergic disorders like eczema & food allergies are more likely to develop other allergic conditions like allergic rhinitis and allergic asthma.
Eczema is usually the first of these disorders to present; usually within 3-12mo of life. This is followed by the onset of food allergies that peak by 2 years of age. Eczema and common food allergies to milk, egg & soy usually improve with age. Allergies to shellfish and nuts tend to persist into adulthood.
Allergic rhinitis and allergic asthma tend to develop later in childhood- during the pre-school years. Both of these conditions can improve with time but tend to persist.
The underlying problem occurs when an immature immune system begins to react inappropriately to common exposures (like dust mites, pollens, animal dander, etc). We’re not sure why the immune system does this but we think the ‘hygiene hypothesis’ has something to do with it. The main premise of the ‘hygiene hypothesis’ is that children exposed to infections, parasites and allergens at an early age allow their immune systems to develop normal responses. Environments free of these exposures, like ones found in the Western world, lead the immune system to react to otherwise harmless substances.
So is there anything we can do to interrupt this ‘allergic march’? Scientists have been researching this topic feverishly. Primary prevention of allergic disease, before a child is born, has been frought with conflicting data. Breast-feeding exclusively for the first 4 months of life seemed to have some positive effect on the development of allergic disease, but this data has not held up. Several other benefits still lead us to still suggest this to new moms. Delaying the introduction of solid foods until 4 mo of age remains a current recommendation although that may change as more light is shed on the issue. It is much clearer that maternal smoking during pregnancy and in early life directly correlates with recurrent wheezing and the possible development of food allergies in infancy. Much research is being done on exposure to pro-biotics and early exposure to animals in the home.
Secondary prevention targets those children that are ‘at risk’ or have early manifestations of allergic disease. Allergic asthma is the most severe of these disorders and can lead to long-term lung damage. Any children with early allergic conditions like food allergies or eczema should be closely screened and followed. There is data to suggest that by intervening early with allergen immunotherapy or possibly even anti-histamines, we may be able to prevent the progression to or severity of allergic asthma. Also, treating asthma early and aggressively will optimize a child’s lung development and prevent long term damage to the lungs. Households with asthmatic children should be smoke-free. If a child has allergic asthma and is allergic to animals, their home should be free of those animals to minimize the amount of inflammation being caused by the immune response to the animal.
Knowledge is power and your allergist is a great resource. Knowing what allergic conditions may be lurking down the road gives you and your doctor the opportunity to identify and treat them early and potentially even prevent them from developing. So enjoy the band knowing you don’t have to march to their beat!