Preterm Birth Is Associated with Reduced Risk of Atopic Dermatitis and a Distinct Allergic Comorbidity Profile in Early Childhood

BACKGROUND: Pediatric atopic dermatitis (AD) is the most common inflammatory disease of childhood and is closely linked to the subsequent development of food allergy, asthma, and rhinitis. There is currently limited insight into the occurrence of AD and allergic comorbidity in early childhood according to gestational maturity. OBJECTIVES: To investigate the occurrence of AD, food allergy, asthma, and rhinitis in term and preterm children from birth to age 4-5 years. METHODS: A prospective birth cohort of 389 children (261 term, 128 preterm) was followed from birth to 4-5 years. Clinical visits were conducted at birth, 2 months, and 12 months, with additional visits for skin signs of AD during the first two years. At age 4-5 years, parents completed a structured telephone interview. We compared the prevalence, age at onset, and persistence of AD and allergic comorbidities between preterm and term children using Mann-Whitney U and Fisher's exact tests. RESULTS: The overall prevalence of AD was 29.6% at age 2 years and 33.0% at 4-5 years. Preterm children had a lower prevalence of AD (19.2% vs. 39.8%, p < 0.0001), later AD onset (median 12.0 vs. 7.5 months, p < 0.01), milder disease severity (median EASI 1.4 vs. 4.8, p < 0.01), and less persistent AD (11.5% vs. 19.9%, p < 0.0001) than term children. Among children born preterm and term, the prevalence of food allergy, asthma, and rhinitis at ages 4-5 years was 1.6% vs. 3.1%, 20.0% vs. 13.0%, and 6.2% vs. 4.6%, respectively. No preterm children with AD (n=25) developed food allergies within 4-5 years compared to 6.7% among term-born children, whereas asthma prevalence was higher among preterm children with AD (36.0%) compared to term children with AD (17.3%) (p=0.05). CONCLUSION: In this cohort, preterm birth was associated with a lower observed incidence of AD, with later onset and a milder and less persistent disease course. Among children with AD, those born preterm had no food allergy and a higher prevalence of asthma compared with term-born children.