SOURCE: Chang YS, Huang YC. J Am Acad Dermatol 2017;77:441-447.e6.

Rosacea is a common dermatologic disorder of uncertain etiology that often is refractory to therapy. Although numerous interventions have been tried, no cure for rosacea is at hand. Antibiotics (e.g., tetracyclines, metronidazole), beta-blockers (e.g., propranolol), alpha-beta-blockers (e.g., carvedilol), systemic steroids, and calcineurin inhibitors (e.g., tacrolimus) have demonstrated some degree of success, but many patients must rely on polypharmacy for adequate symptom control.

An association of the Demodex mite and rosacea has been recognized for more than 50 years. Indeed, antiparasitic medications (ivermectin, permethrin) recently have been shown to produce a favorable effect on rosacea. To better delineate the Demodex-rosacea relationship, Chang and Huang performed a meta-analysis of studies comparing the prevalence of Demodex and the Demodex density (intensity of mite colonization) in patients with rosacea vs. controls. Patients with rosacea were nine times more likely to be infested with Demodex than controls. Similarly, Demodex density was statistically significantly higher in rosacea patients.

The role of Demodex in rosacea appears to be well demonstrated. Since eradication of Demodex is insufficient to resolve rosacea, other pathophysiologic pathways also must be involved.