Real-World Onset of Atopic Comorbidities Relative to Atopic Dermatitis in Pediatric Patients

Patients with atopic dermatitis (AD) have a high atopic comorbidity burden. Although traditionally seen as beginning with AD and progressing to other atopic comorbidities, the “atopic march” model does not fit all patients. This manuscript describes the onset of atopic comorbidities among children newly diagnosed with AD. This retrospective, observational, cohort study used data from the Israeli Maccabi Healthcare Services. Patients (< 18 years) first diagnosed with AD during 2000–2019 with ≥ 12-month enrollment before and after AD diagnosis were included. Outcomes included cumulative asthma, allergic rhinitis (AR), and food allergy (FA) prevalence. Patients were grouped by age at AD diagnosis (< 3, 3–5, 6–11, and 12–17 years). Of 177,081 included patients, 60.4% were < 3 years old at AD diagnosis. The baseline asthma prevalence (at or before AD diagnosis) was lower in children aged < 3 versus ≥ 3 years at AD diagnosis (10.6% versus 26.3–28.5%). The baseline AR prevalence increased with age from 2.2% (< 3 years) to 23.2% (12–17 years), while FA decreased from 4.9% (< 3 years) to 2.1% (12–17 years). Cumulative asthma and FA prevalence increased sharply in the year following AD diagnosis among children diagnosed at < 3 years old. The cumulative ≥ 1 asthma/AR/FA prevalence increased to approximately 50% by 10 years after AD diagnosis. Children diagnosed with AD at an early age mostly acquire atopic comorbidities within 1 year following AD diagnosis, while children diagnosed later have often already developed them. Eventually, all pediatric patients with AD display a similar, significant burden of atopic multimorbidity. Graphical abstract available for this article. Not applicable. People with eczema (also known as atopic dermatitis) often have related diseases, including asthma, hay fever (or allergic rhinitis), and food allergies. Data suggest that eczema develops first, followed by these other diseases (the “atopic march”). This study used healthcare data from Israel to examine how many, and how quickly, children with eczema developed related diseases after their eczema diagnosis. Most children were less than 3 years old when they were first diagnosed with eczema, at which time 16% of them already had a related diagnosis. The percentage of children in this age group with asthma, hay fever, and/or food allergies increased rapidly, to nearly 30% just 1 year later, and almost 50% after 10 years. In contrast, children whose first eczema diagnosis was when they were older (3─17 years old) were much more likely to already have a related diagnosis (nearly 40%), but this then only increased gradually, again reaching around 50% after 10 years. The sharpest increase in asthma and food allergies occurred within 1 year following eczema diagnosis in the youngest age group (children less than 3 years old).