Atopic Dermatitis Closely Linked to Prurigo Nodularis in Meta-Analysis

Credit: Alexander Grey/Unsplash

A recent systematic review and meta-analysis has shed light on the strong connection between atopic dermatitis and prurigo nodularis, suggesting the potential for bi-directionality in the development of these chronic skin conditions.¹

The extensive search of medical data up to February 2024 revealed a statistically significantly elevated risk of atopic dermatitis in patients with prurigo nodularis, with a greater incidence of prurigo nodularis in patients with atopic dermatitis, derived during random-effects meta-analysis.

“The strength of this association, particularly evident in the progression from prurigo nodularis to atopic dermatitis, sheds light on the complex relationship between these conditions,” wrote the investigative team, led by Wei Li, MD, PhD, department of dermatology, The Second Affiliated Hospital, Zhejiang University School of Medicine.

Development of atopic dermatitis is a collision of genetic predisposition, immunological factors, skin barrier defects, and environmental factors.² In patients with long-standing and severe atopic dermatitis, prurigo nodularis is a common complication, defined by itchy dome-shaped papules and nodules varying in size.

Although its pathophysiology is incompletely understood, prurigo nodularis stems from chronic scratching and subsequent skin changes—similar to atopic dermatitis, it can lead to significant physical and psychological harm.³ Evidence has clinically linked atopic dermatitis to prurigo nodularis, but the extent of this association has only recently been quantitatively examined, according to Li and colleagues.¹

For this systematic review and meta-analysis, the team evaluated the link between atopic dermatitis and prurigo nodularis, including whether patients with atopic dermatitis are at an increased risk of prurigo nodularis and whether patients with prurigo nodularis exhibit higher atopic dermatitis rates.

A comprehensive search was performed in PubMed, EMBASE, Scopus, and the Cochrane Library, to identify studies measuring this link, from inception to February 2024. Observational studies reporting the incidence or prevalence of prurigo nodularis in patients with atopic dermatitis or atopic dermatitis in patients with prurigo nodularis were included for assessment.

The search revealed 1094 citations—a thorough review of titles and abstracts excluded 1058 citations and 31 studies were excluded after a full-text review, leaving 5 studies incorporated into the systematic review and the quantitative meta-analyses. These 5 studies encompassed 5463 adult patients with atopic dermatitis and 363,519 control adults, and 12,902 patients with prurigo nodularis and 5,075,024 control patients.

Using random-effects meta-analysis, Li and colleagues identified a notably elevated risk of atopic dermatitis in patients with prurigo nodularis, compared with the control cohort (pooled unadjusted odds ratio [OR], 16.85; 95% CI, 6.13–46.31).

A single study on 5463 patients with atopic dermatitis compared the prevalence of prurigo nodularis in patients with atopic dermatitis and controls. These data showed a higher prevalence of prurigo nodularis in patients with atopic dermatitis (2.00%; 95% CI, 1.62–2.37), compared with controls (OR, 12.5; 95% CI, 10.2–15.3).

However, Li and colleagues noted the importance of caution in interpreting these findings, citing the variability within the studies and the need for further research into the prevalence of prurigo nodularis within the population with atopic dermatitis.

“Nevertheless, the amalgamation of these findings underscores the importance of heightened vigilance for prurigo nodularis in atopic dermatitis patients and vice versa, advocating for a more nuanced approach to managing these intertwined dermatological conditions,” they wrote.

References

1. _{Li W, Pi Y, Xu J. Association between atopic dermatitis and prurigo nodularis: a systematic review and meta-analysis. Int J Dermatol. Published online September 29, 2024. doi:10.1111/ijd.17493}
2. _{Xu AZ, Alexander JT. Topical Therapies for Atopic Dermatitis. JAMA. 2023;330(18):1791-1792. doi:10.1001/jama.2023.17719}
3. _{Müller S, Zeidler C, Ständer S. Chronic Prurigo Including Prurigo Nodularis: New Insights and Treatments. Am J Clin Dermatol. 2024;25(1):15-33. doi:10.1007/s40257-023-00818-z}