The atopic march is characterized by a sequence of immunoglobulin E (IgE) antibody responses triggering allergic symptoms that appear early in life. These allergic symptoms persist over years and often reoccur with age.
Statistically speaking, 50 percent of infants with eczema develop asthma at a later stage. Thirty-three percent will develop a food allergy. For children, the most common triggers for food allergies are eggs, milk, and peanuts. Food allergies diagnosed in early childhood are a risk factor for allergic rhinitis (hay fever) and asthma at a later stage in life. Still, it is important to note that this description of progression is not the exclusive development. Not every child suffering from eczema will end up developing asthma later in life.
Do genetics play a role?
Researchers have found out decades ago that allergies tend to run in families. The tendency to develop allergies is often (but not exclusively) hereditary. It is passed down from parents to their children through their genetic makeup.
Note: Children do not automatically inherit their parents’ allergies, but they might inherit a certain likelihood of developing allergies. At the same time, some children show allergic reactions despite their parents and other family members not being allergic.
Can the allergic march be prevented?
There is no definite answer about whether the development of eczema and the progression of the allergic march is preventable. The solution might lie in between genetic, environmental and diet specific factors. Recent research suggests that the maintenance and repair of the epidermal skin barrier of infants might be a preventive measure.
The exposure to secondhand tobacco smoke, both after birth and during the gestational period, has been identified as a strong risk factor related to the development of asthma in children. Many studies confirm that mothers who smoke during pregnancy and after birth significantly raise their children’s risk for allergic sensitization to food proteins from hen’s eggs and cow’s milk.
Recent studies suggest that expecting mothers should eat a healthy and balanced diet. This includes fruits and vegetables, fish, vitamin D and probiotics to reduce the risk of their baby developing eczema. Still, more research needs be done to confirm these specific maternal lifestyle factors as a method of prevention. Likewise, the role of breastfeeding to prevent the development of atopic allergy symptoms remains controversial. However, a significant number of studies shows that breastfeeding may decrease the likelihood of developing eczema, asthma, and cow’s milk allergy.
Statistics: from eczema to asthma
A study based on the US population has shown that the development of eczema starts in the first few years of life. The study looked at affected children from 3 to 11 years of age and found that 85 percent of those children have suffered from eczema before the age of 5. 45 percent developed the condition during their first 6 months of life, 60 percent in the first year of life.
Less than half of children “outgrow” eczema by the age of 7, and only 60 percent of them have a resolution by adulthood. These numbers indicate that the development of eczema is of chronic nature. It is still unclear how patients outgrow their eczema and therefore halt the allergic march. Genetics and environmental factors likely play a role.
Eczema during childhood has proven to be a major risk factor for the development of asthma. Approximately 70 percent of patients suffering from severe eczema develop asthma. On the other hand, only 20-30 percent of patients with mild eczema and around 8 percent of the general population develop asthma.
Additionally, studies have shown that the severity of eczema directly correlates with the risk of developing rhinitis (hay fever). Eczema in infants can be the cause for hay fever in childhood. Therefore, researchers believe that hay fever in children might be preventable by treating eczema and improving the skin barrier. Pediatricians recommend routinely moisturizing a baby’s skin with low-allergenic moisturizing creams.
As for the role of food allergies in the atopic march, research has shown that eczema and food allergies commonly co-exist in infants. It is still unclear whether food allergy is the initial stage of the atopic march in infants, or whether it is an independent condition predicting the atopic march.
There is clinical and genetic evidence as well as experimental studies suggesting that eczema in infants can be the starting point for the development of allergic rhinitis and asthma.
For new parents, it is important to identify eczema and atopic dermatitis on their baby’s skin. Early life presents a critical window of opportunity for therapeutic intervention. By keeping a baby’s skin well moisturized and repairing the skin barrier, the allergic march and therefore the development of asthma might be preventable.
Sources: allergyasthmanetwork.org, worldallergy.org, Journal of Clinical & Cellular Immunology