Researchers explain the food allergy 'march' found in some children

Evan Walker
Evan Walker TheMediTary.Com |
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Researchers say the rare food allergy eosinophilic esophagitis is more prevalent among non-white children than previously thought. FatCamera/Getty Images
  • In the largest-ever study of pediatric allergies, researchers from the Children’s Hospital of Philadelphia analyzed electronic health records from more than 200,000 children.
  • The researchers reported that eosinophilic esophagitis (EoE), a rare food allergy previously associated with white males, is more common among non-white people than previously believed.
  • They say this research underscores the significant impact of allergic conditions on children’s well-being and emphasizes the need for a precise understanding of their prevalence and risk factors, while also highlighting the importance of collaborative diagnoses between healthcare providers and families.

In new research, published in the journal Pediatrics, scientists are reporting on how allergic conditions can significantly impact the quality of life of children and are among the leading factors affecting their well-being.

They say their findings confirm a widespread phenomenon known as the “allergic march,” where allergies initially manifest as eczema, followed by food allergies, asthma, and environmental allergies.

The study also revealed that the rare food allergy known as eosinophilic esophagitis (EoE), thought to predominantly affect white males, is more prevalent among the non-white population than previously understood.

Previous investigations into the prevalence and trends of allergies have relied on surveys filled out by families.

However, the approach taken in this study involved accessing and reviewing electronic health records, providing the researchers with data directly from healthcare providers.

The researchers say this method enabled them to analyze patterns at a population level, track changes over time, and reduce the potential for reporting bias.

Researchers utilized a vast database known as the Comparative Effectiveness Research through Collaborative Electronic Reporting (CER2) Consortium.

This database contains information from more than 1 million children from various primary care practices and Healthcare systems across the United States.

The researchers focused their investigation on five specific allergic conditions: eczema (also called atopic dermatitis), anaphylactic food allergies (severe allergic reactions to certain foods), asthma, allergic rhinitis (commonly known as hay fever) and EoE (the less-known food allergy that affects the esophagus).

For each of these conditions, the researchers analyzed data to determine the age at which children were diagnosed and whether they developed other allergic conditions over time.

In total, they identified 218,485 children who had allergies and were observed for more than 5 years between 1999 and 2020. They found that:

  • Eczema typically started around 4 months of age.
  • Both anaphylactic food allergies and asthma commonly began at approximately 13 months old.
  • Allergic rhinitis usually started around 26 months of age.
  • EoE typically appeared around 35 months of age.

Among the anaphylactic food allergies, the most frequently diagnosed ones were peanut allergies (1.9%), followed by egg (0.8%) and shellfish (0.6%).

About 13% of the children had two different allergic conditions simultaneously.

Children with respiratory allergies such as asthma and allergic rhinitis were more likely to have both of these conditions and sometimes other allergic conditions as well.

The researchers also made a discovery regarding anaphylactic food allergies when diagnosed by healthcare providers.

They found that the prevalence of these allergies, as determined by healthcare professionals, was 4%. This is about half the prevalence compared to studies that relied on surveys filled out by families.

The researchers said this suggests that previous studies might have mistakenly included non-anaphylactic food intolerances in their findings.

The scientists said their research offers a significant insight into the occurrence and trends of allergic diseases in children, finding that EoE may affect a more diverse population than previously believed.

This understanding is vital because families and pediatricians often observe symptoms that might signal the development of allergies in children.

They said future research should try to identify groups of people who are more likely to have allergies and may benefit from early testing.

They recommended scientists also look into any differences in how the disease affects different communities.

“I really like this study because it involves a lot of patients – close to a quarter of a million children – using some sophisticated electronic health records,” said Dr. Daniel Ganjian, FAAP, a pediatrician at Providence Saint John’s Health Center in California who was not involved in this research.

“It also sheds some more light about the characteristics of the allergic march that we see in some children,” Ganjian told Medical News Today.

Dr. Stephanie Leeds, a pediatric allergist and immunologist at Yale New Haven Children’s Hospital in Connecticut who also was not involved in the study, agreed.

She told Medical News Today that “it is heartening that researchers continue to look at patterns in the development of pediatric allergy, particularly as there are now evidence-based guidelines for prevention of certain allergic disease, such as peanut allergy.”

As with many diseases, prevention is preferable to treatment. Perhaps increasing research into patterns of disease development will help us determine those at highest risk of developing disease (and therefore those who might benefit the most from prevention efforts).

Dr. Stephanie Leeds

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