Patients with rosacea display reductions in protective organisms and an enrichment of harmful organisms in the skin’s microbiota, a case-control study in the American Journal of Clinical Dermatology reports.
Patients with rosacea (n=19), including erythematotelangiectatic, papulopustular, or both, treated at the Johns Hopkins Outpatient Center were matched with patients without rosacea (n=19). The study examined DNA taken from skin swabs of both the nose and bilateral cheeks of each participant. The researchers also performed and analyzed the sequencing of the V3V4 region of the bacterial 16S ribosomal RNA gene.
In patients with erythematotelangiectatic rosacea, the skin microbiota was significantly depleted in Roseomonas mucosa compared with that of control patients (P =.004). Papulopustular rosacea was associated with enrichment in three organisms: Campylobacter ureolyticus (P =.001), Corynebacterium kroppenstedtii (P =.008), and oral flora Prevotella intermedia (P =.001).
Patients with both erythematotelangiectatic and papulopustular rosacea had the highest relative abundance of C kroppenstedtii (19.2%). In addition, C kroppenstedtii was also observed in the skin of patients with papulopustular rosacea (5.06%) and erythematotelangiectatic rosacea (1.21%). The highest relative abundance of C kroppenstedtii affected the cheeks and nose (2.82%), rosacea of the cheeks but not the nose (1.93%), and matched control patients (0.19%).
Limitations of the study included the small sample size, the low recruitment of male patients, and the exclusionary focus on bacterial microbiota rather than the additional inclusion of viruses and fungi.
“No significant similarity in beta diversity between patients with rosacea and controls was demonstrated,” the researchers added, “indicating that no one rosacea subtype displays an overall species diversity more closely aligned with controls than any other subtype.”
Disclosure: A study author declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.
Rainer BM, Thompson KG, Antonescu C, et al. Characterization and analysis of the skin microbiota in rosacea: a case-control study [published online September 9, 2019]. Am J Clin Dermatol. doi:10.1007/s40257-019-00471-5