Children with allergies nine times more likely to develop emerging, severe chronic food allergy, warns study

16 Oct 2018 --- Children with known skin, food and respiratory allergies should be screened for an emerging, chronic food allergy called eosinophilic esophagitis (EoE), warns a study published in the Journal of Allergy and Clinical Immunology: In Practice. Pediatric allergists who analyzed a group of children from birth to adolescence say that EoE should be considered a later component of the “allergic march” – the natural progression in which many children develop a series of allergies.

“The more allergies a child has, the higher is that child's risk of developing EoE,” says study leader David A. Hill, MD, Ph.D., an allergist at Children's Hospital of Philadelphia (CHOP).

“The connection among these allergies suggests a common underlying biological cause, and also may imply that if we can successfully treat an earlier type of allergy, we may prevent later allergies,” he adds.

What is EoE?
EoE is a painful inflammation of the esophagus, the food tube between the mouth and stomach.

In contrast to many other potentially life-threatening anaphylactic food allergies (e.g., to peanuts) EoE has low mortality, but high morbidity. It has slow-onset symptoms, such as pain in swallowing, reflux, stomach ache and, in some cases, even food impaction (in which food may become lodged in the esophagus).

Both types of allergies are in triggered by specific foods, but the triggering food in EoE may not be obvious, and a child may need to follow a strict and regulated diet until it can be uncovered.

EoE may be slow to manifest, sometimes misdiagnosed or undiagnosed until adolescence.

The study
The research team analyzed health records in a longitudinal cohort of over 130,000 patients in the CHOP pediatric network followed from birth to adolescence, to determine whether and when patients started experiencing allergic diseases. The researchers also compared the risk of developing EoE between allergic and non-allergic children.

The “allergic march,” a pillar concept in allergy, is usually compressed into the first five years of life. The typical childhood progression, says Hill, is a skin allergy such as atopic dermatitis followed by an anaphylactic food allergy, then a respiratory allergy, such as asthma. The current study was the first to suggest that EoE was a component of the allergic march.

“We found that if children had three allergies other than EoE, they were nine times more likely to develop EoE than children with no pre-existing allergies,” says Hill. 

The peak age of EoE diagnosis was found to be 2.6 years. In addition, children with EoE had a higher risk than those without EoE of developing the respiratory allergy allergic rhinitis – commonly referred to as seasonal allergy. A key implication of the current study, says Hill, is that primary care clinicians should incorporate early EoE screening in children who have other allergies.

Future research requires investigation of the underlying biological mechanisms among different allergies: “Ultimately, we hope to find that intervening earlier in the allergic march, for example, by treating allergic skin conditions, may interrupt the march and prevent the child from developing later disorders such as EoE,” says study co-author Jonathan M. Spergel, MD, Ph.D.