The Allergic March: How Early Allergies Can Increase Vulnerability to Later Allergies, and How Sound Food Allergy Management Can Reduce Risk

The allergic march, sometimes called the atopic march, is a sequence of allergic diseases that often begins early in life. Eczema (an itchy, persistent rash) and food allergy typically appear early in the march; conditions that tend to develop later include asthma (inflammation that narrows the airways and makes breathing difficult) and hay fever (allergic rhinitis, with symptoms resembling a cold). However, the allergic march can be unpredictable: not everyone who develops early allergies will follow this progression or experience all these conditions. 

As the allergic march suggests, when a person develops one allergy, they are at higher risk to develop others. In 2008, the Centers for Disease Control and Prevention reported that children with food allergy are two to four times as likely to experience skin allergies, respiratory allergies and asthma than children without food allergy. We also know that about 40 percent of children with food allergy are allergic to more than one food.  

Cow’s milk allergy is one of the most common early allergic conditions: a survey published in 2018 found that 53 percent of infants who develop food allergy in the first year of life react to cow’s milk. Eczema can be a symptom of cow’s milk allergy, with the rash being triggered or made worse by exposure to cow’s milk protein. When eczema damages the skin barrier, proteins from food or the environment can enter the body through the skin and provoke an immune response. As a result, eczema increases an infant’s risk for becoming sensitized to new allergens and possibly developing new allergies.

Given that cow’s milk allergy can trigger and inflame infant eczema, it’s important to manage cow’s milk allergy effectively to help preserve the skin barrier and prevent sensitization to new allergens. A recent survey conducted by OnePoll on behalf of Mead Johnson Nutrition™ found that only four in 10 moms are aware that a cow’s milk allergy can be indicative of more allergies later in life, while slightly more than half of moms – 55 percent – know that there are ways to reduce the likelihood of a baby’s future allergies.

Infants can be exposed to cow’s milk protein allergens in breastmilk if their mothers consume cow’s milk products, so effective allergy management requires a breastfeeding mother to eliminate cow’s milk products from her diet. For cow’s milk-allergic infants fed formula or a combination of formula and breastmilk, options for proper nutrition* include extensively hydrolyzed casein formulas, in which a protein from cow’s milk is broken down to eliminate allergens, and so-called elemental formulas, which are based on amino acids, the building blocks of proteins.

Researchers have found that some formula options outperform others as nutritional interventions to slow or reduce the likelihood of the allergic march in the first three years of life. In a study spanning infancy to age 36 months, children with cow’s milk allergy received one of two hypoallergenic formula options.  Half of the children were given extensively hydrolyzed casein formula, while the other half received a nearly identical formula with one new ingredient, the probiotic bacteria Lactobacillus rhamnosus GG.  Compared to children who were fed conventional hypoallergenic formula, the children who received the probiotic formula were less likely to develop new allergies and more likely to outgrown their allergy to cow’s milk. Previous dietary studies of cow’s milk allergy management have also shown better outcomes with extensively hydrolyzed casein formula plus Lactobacillus rhamnosus GG versus extensively hydrolyzed casein formula or amino acid-based formula.

*Eight to 14 percent of infants with symptoms of cow’s milk allergy also react to soy, so soy-based formulas are not generally recommended for infants who are allergic to cow’s milk.


This article and the Infancy: Early Steps content series are powered by Mead Johnson’s Allergic Action Campaign.