Phenotypic differences of atopic dermatitis stratified by age.

Background:Atopic dermatitis (AD) is common across all ages. Understanding heterogeneous age-related phenotypes may improve AD management. Objective:To determine age-related clinical phenotypes of AD. Methods:A prospective, dermatology practice-based study was performed (n = 380). AD severity was evaluated using questionnaires and full-body examination. Phenotypes were determined using latent class analysis. Results:There were 23 (6.1%) pediatric patients (<18 years), 176 (46.3%) young adults (18-39 years), and 181 (47.6%) older adults (≥ 40 years). Both young and older adults experienced less AD on ankles (adjusted odds ratio [95% confidence interval]: 0.41 [0.19-0.90], 0.43 [0.20-0.94]), moderate-severe AD on flexures (0.47 [0.26-0.87], 0.30 [0.16-0.56]), pityriasis alba (0.24 [0.11-0.52], 0.07 [0.03-0.18]), oozing lesions (0.44 [0.25-0.79], 0.35 [0.20-0.63]), moderate-severe excoriations (0.49 [0.28-0.85], 0.44 [0.26-0.76]), and severe itch (adjusted β [95% confidence interval], -1.46 [-2.63 to -0.29]; -1.79 [-2.94 to -0.65]) compared with pediatric patients. Young adults experienced more AD around the eyes (2.92 [1.21-7.02]). Older adults experienced more AD on elbows (0.34 [0.19-0.64]), nipples (0.40 [0.16-0.99]), knees (0.27 [0.14-0.53]), keratosis pilaris (0.38 [0.15-0.98]), and lichenification (0.47 [0.22-0.98]). Four classes were identified for distribution of AD and associated signs. Conclusion:Distinct phenotypes exist by age with younger patients experiencing more AD signs and symptoms. Clinicians should consider them when managing AD.