Millions of US Adults Have Multiple Forms of Eczema, Study Finds

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Nearly 1 in 10 US adults has at least one form of eczema, and for many, it does not stop there. A new study from the National Eczema Association, using data from the National Institutes of Health’s All of Us (AoU) Research Program, found that 18% of those with eczema have multiple types, complicating diagnosis and treatment.

Seborrheic dermatitis (SD) and atopic dermatitis (AD) were the most common forms, with SD affecting 4.3% of adults and AD 2.5%. Among those with multiple diagnoses, the most frequent combinations were AD and SD (25.9%), allergic contact dermatitis (ACD) and SD (15.3%), and AD and ACD (13.8%). SD was also the most common first diagnosis, occurring in 33.1% of cases.

The research analyzed deidentified electronic health records (EHRs) from a large and diverse national cohort, identifying eczema cases using standard medical classification codes. The estimated prevalence of eczema in this study—9.6%—was higher than previous reports, which ranged from 5.4% to 5.6%. Researchers attribute this increase to a broader definition of eczema and a larger sample size.

While the prevalence of SD in this study aligns with global estimates (4.4%), data on the overlap of eczema types in US adults remains scarce. A previous study in Germany found that 3.8% of adults with a history of AD also had SD, whereas this new data suggests a much higher co-occurrence rate of 18.4%.

These findings highlight the need for more comprehensive treatment approaches, as patients with multiple eczema types may face greater challenges in managing symptoms. However, the study has limitations, including potential misclassification of diagnoses due to overlapping symptoms and the possibility that some diagnostic codes were assigned for billing purposes rather than definitive clinical reasons. Researchers suggest further validation studies to confirm the accuracy of these diagnoses.

For clinicians, the study underscores the importance of recognizing co-occurring eczema types when developing treatment plans. With nearly 1 in 5 adults with eczema experiencing multiple diagnoses, a one-size-fits-all approach may not be effective. Further research on real-world treatment outcomes is needed to optimize care for these patients.

Source: Loiselle AR, Johnson JK, Smith Begolka W. Prevalence and co-occurrence of eczema types in U.S. adults: Insights from the All of Us research program. Journal of Investigative Dermatology. Published online March 3, 2025. doi:10.1016/j.jid.2025.02.136