Etiology of Rosacea The etiology of rosacea is unknown, but some proposed associations include Abnormal vasomotor control Impaired facial venous drainage Increased follicle mites (Demodex folliculorum) Increased angiogenesis, ferritin expression, and reactive oxygen species Dysfunction of antimicrobial peptides (eg, cathelicidin) Diet plays no consistent role, but some agents (eg, amiodarone, topical and nasal corticosteroids, high doses of B6 and B12) may worsen rosacea.