Association between atopic dermatitis and prurigo nodularis: a systematic review and meta-analysis

Atopic dermatitis (AD) and prurigo nodularis (PN) are chronic dermatological conditions marked by severe itching and the presence of eczematous lesions such as papules and nodules. Both diseases can pose significant physical and psychological harm, leading to poor quality of life. Notably, AD and PN were clinically linked in the past, with suggestions by researchers that PN might be a distinct clinical phenotype of AD. However, the extent of their relationship had not been fully quantified until our recent investigations. Through a meticulous systematic review and meta-analysis adhering to the PRISMA guidelines, we extensively searched databases, including PubMed, EMBASE, Scopus, and the Cochrane Library, up to February 18, 2024. Our random effects meta-analysis presented a strikingly increased risk of AD in patients suffering from PN as opposed to control groups (pooled unadjusted odds ratio [OR], 16.85; 95% confidence interval [CI], 6.13-46.31; I² = 100%). Correspondingly, an elevated prevalence of PN was identified in subjects with AD (2.00%; 95% CI, 1.62-2.37%). These findings underscore the close association between AD and PN, suggesting a multifaceted overlap and potential bi-directionality in developing these skin conditions. However, further comprehensive studies are essential to validate these associations and understand their precise clinical implications, with the ultimate goal of refining patient management strategies.