Background: Allergic contact Dermatitis® (ACD) in older adults (OA) represents a significant health burden, but few studies examine the prevalence and characteristics of contact allergy and ACD in this population. Objective: To compare positive and clinically relevant patch test results in OA versus younger adults (YA) and children. Methods: Retrospective analysis of patch test results obtained in OA (≥65 years), YA (19-64 years), and children (≤18 years) by the North American Contact Dermatitis® Group, 2009 to 2020. Results: Of 28,177 patients patch tested, 5366 (19.0%) were OA. OA were more likely to have a final primary diagnosis of ACD as compared with YA (50.8% vs 49.2%, P = 0.035) and children (44.6%, P < 0.0001). The primary site of Dermatitis® also differed by age group, with OA having a higher proportion of Dermatitis® affecting the trunk, scalp, anogenital region, and "under clothing," and a lower proportion of Dermatitis® affecting the face, lips, and feet. Limitations: Retrospective design, lack of follow-up, and referral population. Conclusion: OA were as likely and were statistically even more likely to have a final primary diagnosis of ACD compared with YA and children. Anatomic site of Dermatitis® also differed by age group. This underscores the need for patch testing in OA when ACD is suspected.
This systematic review and meta-analysis aimed to explore the association between atopic Dermatitis® (AD) and alopecia areata (AA). A comprehensive search was conducted in PubMed, Embase, Cochrane, and Web of Science from the inception of each database to November 10, 2022 for relevant studies. As there is a potential bilateral association between the 2 diseases, we assessed the prevalence/incidence of AA in patients with AD and the prevalence/incidence of AD in patients with AA. A total of 29 studies involving 11,233,448 participants were included in this analysis. AA was the exposure factor in 23 studies, AD in 7 studies, and both in 1 study. The meta-analysis revealed that the prevalence of AD was 11.2% (7.7%-15.1%) in patients with AA, and the prevalence of AA was 3.2% (95% confidence interval [CI]: 0.0%-11.5%) in patients with AD. The incidence of AD in AA patients was found to vary with age (P = 0.07). Based on 7 studies, there was a significant association between AD and AA when AA was the exposure factor [odds ratio, OR, = 4.537 (95% CI: 2.409-8.544)]; based on 10 studies, there was also a significant association between AD and AA when AD was the exposure factor [OR = 2.643 (95% CI: 1.737-3.995)]. In conclusion, this meta-analysis demonstrated the 2-way association between AD and AA, providing a clinical reference for disease prevention and control.