The study, published on 28 September 2026 as a research letter in volume 318 of the journal, takes a retrospective approach. Rather than recruiting patients prospectively and following them over time, the authors mined existing electronic health records to identify individuals who received a rosacea diagnosis and to characterize the population in which new diagnoses appear. This design is increasingly popular in epidemiology because it leverages the enormous volume of clinical documentation generated by routine care, allowing researchers to examine disease patterns across millions of patients without the cost and duration of a traditional cohort study.

The data source underlying the analysis is TriNetX, a federated health research network that aggregates de-identified electronic medical records from contributing healthcare organizations, primarily large academic medical centers and integrated health systems across the United States. The platform allows investigators to run queries against this pooled data while the records themselves remain with the originating institutions, a structure that has made it a workhorse for observational studies in recent years. The authors note that the data supporting their findings are publicly available on TriNetX, which aligns with a broader push toward transparency and reproducibility in real-world evidence research.

Why does an incidence estimate for rosacea matter so much? Prevalence figures, which describe how many people live with the condition at a given time, have varied widely in the literature, in part because rosacea is a clinical diagnosis without a definitive laboratory test, and in part because many people with mild symptoms never seek medical care. A widely cited review by Rainer, Kang, and Chien published in Dermato-Endocrinology in 2017 highlighted that estimates of rosacea prevalence have ranged dramatically across populations and study designs, complicating efforts to understand the disease’s true burden. Incidence, the rate of new cases, is even harder to pin down, because it requires distinguishing genuinely new diagnoses from the documentation of longstanding disease in patients who are new to a health system.

The stakes of getting these numbers right extend well beyond academic curiosity. Rosacea is not merely a cosmetic nuisance. Research led by Moustafa, Lewallen, and Feldman, published in the Journal of the American Academy of Dermatology in 2014, examined the psychological impact of rosacea and concluded that the condition carries a substantial emotional burden, with effects on self-esteem, social interactions, and quality of life comparable in some respects to other highly visible chronic skin diseases. Patients describe anxiety about facial flushing in public settings, avoidance of triggers such as spicy food, alcohol, heat, and emotional stress, and frustration with treatments that control but rarely eliminate symptoms. A more recent comprehensive review of rosacea management published in the Journal of Cosmetic Dermatology in 2022 underscored that while therapeutic options have expanded, the condition remains chronic and relapsing for most patients.

Understanding how many people develop rosacea each year informs resource allocation in dermatology, guides pharmaceutical investment in new therapies, and provides a baseline against which future changes, whether environmental, demographic, or diagnostic, can be measured. It also matters for research into the disease’s pathogenesis. Rosacea has been linked to abnormalities in the innate immune system, neurovascular dysregulation, Demodex mites on the skin, and an assortment of genetic and environmental risk factors, but the relative contributions of these mechanisms remain debated. Solid epidemiological data help researchers identify which populations are most affected and where to focus mechanistic studies.

The TriNetX approach also connects this work to a lively methodological conversation. A 2025 critical review by Nassar and colleagues examined the strengths, limitations, and bias considerations of TriNetX in clinical research, noting that while the platform offers unprecedented scale, it inherits the biases of the underlying records. Patients in the network are those who present to participating healthcare organizations, which may skew toward sicker, more insured, or more urban populations. Coding practices vary across institutions, and a diagnosis code for rosacea may reflect anything from a confident specialist diagnosis to a working impression by a primary care clinician. The Stony Brook authors’ decision to publish in a dermatology research journal with the data availability statement pointing back to TriNetX reflects a growing norm of making the provenance of real-world evidence explicit so that readers can weigh these caveats themselves.

Retrospective designs like this one sit within a longer tradition of rosacea epidemiology. One of the most influential prior efforts, a study by Spoendlin and colleagues published in the British Journal of Dermatology in 2012, examined the epidemiology of rosacea in the United Kingdom using routine health records, providing one of the best-characterized national pictures of the disease. Comparing United States figures against such international benchmarks helps clarify whether rosacea truly varies across populations and climates, as some hypotheses about sun exposure and skin phototype would predict, or whether earlier variation simply reflected differences in how the disease was counted. The condition is classically associated with fair-skinned individuals of Northern European descent, but it is increasingly recognized across all skin tones, where it may be underdiagnosed because erythema is harder to visualize on darker skin.

For clinicians, the practical takeaway from this kind of study is a clearer sense of the expected flow of new rosacea diagnoses through the healthcare system, which can inform screening awareness, referral patterns, and patient education. For patients, better epidemiology supports advocacy and awareness efforts, including the kind of public health messaging that has successfully raised the profile of conditions like psoriasis and acne. Rosacea has historically received less attention relative to its prevalence and its documented impact on quality of life, and hard numbers are the currency in which that attention is won.

The research letter format itself is worth noting. Archives of Dermatological Research, published by Springer Nature, offers research letters as a concise vehicle for focused findings, and the brevity of the format means that readers should look to the full article for the precise incidence estimates, stratifications by age and sex, and sensitivity analyses that determine how robust the numbers are. What the publication establishes is a contemporary, data-driven baseline for rosacea incidence in the United States, built on one of the largest aggregated clinical data networks available, from a team at Stony Brook University with no declared competing interests. As real-world evidence continues to reshape dermatological epidemiology, studies of this kind are likely to become the standard reference points against which the field measures both the burden of rosacea and the success of future efforts to treat and perhaps prevent it.

Subject of Research: Epidemiology of rosacea incidence in the United States using real-world electronic health record data

Article Title: Incidence of Rosacea in the United States: a retrospective study using real-world data

Article References: Basharat, R., & Iqbal, J. (2026). Incidence of Rosacea in the United States: a retrospective study using real-world data. Archives of Dermatological Research, 318(1), Article 485. https://doi.org/10.1007/s00403-026-04977-x

Image Credits: AI Generated

DOI: 10.1007/s00403-026-04977-x

Keywords: rosacea, incidence, epidemiology, TriNetX, real-world data, dermatology, retrospective study, electronic health records, skin disease, Stony Brook University, Archives of Dermatological Research, facial redness