Atopic dermatitis shows disparate results both internationally and, within most nations, across racial and economic lines, as this new large-scale meta-analysis shows.
Atopic dermatitis (AD) affects both adult and pediatric populations around the world, and although we have made progress in understanding what causes it, there are still disparities throughout the world in how the disease is treated. When looking at the prevalence of AD, most studies use a few different criteria, including the International Society for Asthma and Allergies in Children (ISAAC) and the United Kingdom Working Party (UKWP) criteria. When looking at large databases, one of the difficulties involved in creating a final homogenous set of data is understanding the different diagnostic criteria that each source study used. On the basis of these disparate data sources, this study, published in the British Journal of Dermatology, provides an analysis of disparities in AD prevalence and burden both within and between countries.
Disparities Hinder the Understanding of AD Prevalence Internationally
On a global scale, AD shows a varied phenotype and natural history, and the criteria that are used vary depending on the population being studied. For example, common scoring systems that rely on skin erythema can underestimate AD severity in darker skin types. After adjusting for erythema scores, Black children have a 6 times higher risk of severe AD compared to their White counterparts, which is an indicator of how difficult these types of international meta-analyses can be to conduct. The meta-analysis also revealed disparities in access to both topical and systemic therapies. Additionally, there was a marked disparity in both ethnic and international presence in clinical trials, with African patients with AD constituting 8.9% of participants in all AD trials.
The Global North Fares Well at the Expense of South America and Africa
Guidelines for determining the presence of AD are present and established in North America, the UK, Europe, and Australia, but not in South America and Africa. Access to systemic agents is also not established in South America or Africa. Additionally, social factors within a nation, such as low income, single-parent households, poor housing quality, and greater environmental exposures are additional risk factors for developing AD. The data support an image of the “global north” having increased access to treatment methods, while also experiencing diminished exposure to factors that increase AD risk.
Mosam, A., & Todd, G. (2023). Global epidemiology and disparities in atopic dermatitis. British Journal of Dermatology. https://doi.org/10.1093/bjd/ljad042