From the Journals

2 in 1: Rosacea-like demodicosis, papulopustular rosacea may be phenotypes of same disease



Papulopustular rosacea (PPR) and rosacea-like demodicosis may be the same disease, according to the authors of a retrospective study.

Currently, there is a lack of consensus among physicians and health care organizations on how Demodex mites affect the development of rosacea. Many experts separate rosacea into two camps: PPR not caused by Demodex and rosacea-like demodicosis caused by Demodex.

Subtype 2: Persistent facial redness with bumps or pimples. Often seen following or with subtype 1.

To address this confusion, Fabienne Forton, MD, a dermatologist in Brussels, and Viviane de Maertelaer, PhD, of the Université Libre de Bruxelles conducted this study to determine the role that Demodex mites play in the development of PPR and rosacea-like demodicosis, which are surprisingly similar. Building off of a previous study of 254 patients with central facial papulopustules, the researchers conducted a secondary analysis of 242 patients; 215 of these patients had central facial papulopustules and persistent erthyema (both considered diagnostic of PPR), and 27 had central facial papulopustules but lacked persistent erythema.

During each evaluation session, each patient underwent two consecutive standardized skin surface biopsies (SSSBs), a small 1 square centimeter sample of the horny skin layer and the follicular content, on each cheek. The first sample, SSSB1, was a superficial sample, and SSSB2, the second sample, was a deep sample. The sum of the two samples, SSSB1+2, also was noted.

During the same session, patients had Demodex densities (Dds) measured. To avoid any confounding factors that could affect facial skin symptoms, Dr. Forton and Dr. de Maertelaer evaluated a subgroup of 132 patients who had not been treated in the previous 3 months and had no other facial dermatoses, such as acne vulgaris and seborrheic dermatitis.

The study revealed that, among the 242 patients in the primary analysis group, those with persistent erythema had higher Dds than did those without and the differences were statistically significant when comparing SSSB2 (208 D/cm2 vs. 130 D/cm2; P = 0.031) and SSB1+2 (298 D/cm2 vs. 191 D/cm2; P = 0.025), respectively.


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