This pattern of greater Dds density among patients with persistent erythema, compared with patients without, also held true among the subgroup of 132 patients who had not received any recent dermatological treatments, but the difference was not statistically significant. Nonetheless, patients with follicular scales did have greater SSSBs than did those without follicular scales.
As part of the study, Dr. Forton and Dr. de Maertelaer analyzed the findings of a case report of a 19-year-old woman who had a facial papulopustular eruption that had been present for 1 year. She had two SSSBs taken on each cheek: the right had follicular scales and papulopustules, and the left was clinically normal. This revealed that she had much higher Dds on the affected cheek than on the clinically normal one (108 and 216 D/cm2 vs. 12 and 20 D/cm2). She was subsequently diagnosed with rosacea-like demodicosis.
After treating the areas with acaricidal ointment, the symptoms improved. But 27 months after stopping maintenance treatments, the facial eruptions reappeared, and the papulopustules were larger than during her original consultation, leading to the diagnosis of PPR. This time, the Dds was high on both cheeks but responded to acaricidal treatment, which indicates that her eruptions were caused Demodex mites.
“All our observations, therefore, highlight the nosological confusion that persists between PPR and rosacea-like demodicosis and the need to update the consensus concerning the definition and classification of rosacea. Moreover, they suggest that PPR and rosacea-like demodicosis may be phenotypes of the same disease,” wrote Dr. Forton and Dr. de Maertelaer. “This concept is supported by our case report, with many features indicating that the second presentation was an evolution of the first.”