Atopic dermatitis: Correlation of distinct risk factors with age of onset in adulthood compared to childhood

Background: Atopic dermatitis (AD) has long been regarded as a primarily pediatric disease. However, there is growing evidence for a high rate of adult-onset AD. We aimed to characterize factors associated with adult-onset versus childhood-onset AD and controls. Methods: We analyzed cross-sectional data of the CK-CARE-ProRaD cohorts Bonn, Augsburg, Davos, Zurich of 736 adult patients stratified by age of AD onset (childhood-onset <18 years: 76.4% (subsets: 0 to 2; >= 2 to 6; v7 to 11; >= 12 to 18); adult-onset >= 18 years: 23.6% (subsets: >= 18 to 40; >= 41 to 60; >= 61) and 167 controls (91 atopic, 76 non-atopic)). Results: We identified active smoking to be associated with adult-onset AD versus controls (adjusted Odds Ratio (aOR) = 5.54 [95% Confidence Interval: 1.06-29.01] vs. controls(non-atopic), aOR = 4.03 [1.20-13.45] vs. controls(atopic)). Conjunctivitis showed a negative association versus controls(atopic) (aOR = 0.36 [0.14-0.91]). Food allergy (aOR = 2.93 [1.44-5.96]), maternal food allergy (aOR = 9.43 [1.10-80.95]), palmar hyperlinearity (aOR = 2.11 [1.05-4.25]), and academic background (aOR = 2.14 [1.00-4.54]) increased the odds of childhood-onset AD versus controls(atopic). Shared AD-associated factors were maternal AD (4-34x), increased IgE (2-20x), atopic stigmata (2-3x) with varying effect sizes depending on AD onset and control group. Patients with adult-compared to childhood-onset had doubled odds of allergic rhinitis (aOR = 2.15 [1.12-4.13]), but reduced odds to feature multiple (3-4) atopic comorbidities (aOR = 0.34 [0.14-0.84]). Adult-onset AD, particularly onset >= 61 years, grouped mainly in clusters with low contributions of personal and familial atopy and high frequencies of physical inactivity, childhood-onset AD, particularly infant-onset, mainly in high-atopic-clusters. Conclusions: The identified associated factors suggest partly varying endo-and exogeneous mechanisms underlying adult-onset versus childhood-onset AD. Our findings might contribute to better assessment of the individual risk to develop AD throughout life and encourage prevention by non-smoking and physical activity as modifiable lifestyle factors.

Automated summary

This study aimed to compare the characteristics of adult-onset and childhood-onset AD. It found an association between adult-onset AD and smoking, and a negative correlation between conjunctivitis and atopic controls. Factors such as food allergy, maternal food allergy, palmar hyperlinearity, and academic background increased the odds of childhood-onset AD. These findings contribute to a better understanding of the risk factors for developing AD throughout life and emphasize the importance of non-smoking and physical activity in prevention.