Controversial issues of hyperinfestation with Demodex mites in rosacea and acne

Demodex mites (D. folliculorum and D. brevis) are the most common ectoparasites found on human skin, with carriage rates reaching up to 100% in older age groups. The majority of the population are asymptomatic carriers; however, an increase in Demodex mite colonies, observed with decreased innate immune activity and epidermal barrier dysfunction, can lead to enzymatic damage of pilosebaceous follicle structures, mechanical blockage of sebaceous gland ducts, activation of pro-inflammatory cytokines, and disruption of microbial balance in the skin. These factors are key in the pathogenesis of sebaceous gland diseases. First identified nearly two centuries ago, Demodex mites remain a subject of ongoing debate regarding their role both in the normal skin microbiome and in the pathogenesis of diseases such as acne, rosacea, perioral dermatitis, seborrheic dermatitis, and others. This review presents current scientific data on the etiology, epidemiology, and pathogenetic role of Demodex mites in the development of acne and rosacea – the most common sebaceous gland diseases. Additionally, methods for etiotropic correction of mite hyperinfestation are proposed.