Human demodicosis: revisit and a proposed classification.

Area of Science:

• Dermatology
• Microbiology
• Parasitology

Background:

• Human Demodex mites (Demodex folliculorum and Demodex brevis) are evolutionarily significant components of the skin microbiome.
• Demodicosis, a skin disease caused by Demodex mites, often mimics other inflammatory dermatoses like rosacea and folliculitis, complicating diagnosis.
• Current understanding and classification of demodicosis lack specificity, hindering effective treatment strategies.

Purpose of the Study:

• To propose a novel classification system for human demodicosis, differentiating between primary and secondary forms.
• To delineate the clinical manifestations associated with primary demodicosis, including spinulate, papulopustular/nodulocystic, ocular, and auricular forms.
• To highlight the association of secondary demodicosis with immunosuppression and identify areas for future research.

Main Methods:

• Review and synthesis of existing literature on human demodicosis.
• Clinical observation and phenomenological description of various demodicosis presentations.
• Comparative analysis of demodicosis with other inflammatory skin conditions.

Main Results:

• Proposed classification of demodicosis into primary and secondary forms.
• Detailed description of four clinical subtypes of primary demodicosis: pityriasis folliculorum, papulopustular/nodulocystic demodicosis, ocular demodicosis, and auricular demodicosis.
• Identification of immunosuppression as a key factor in secondary demodicosis.

Conclusions:

• The proposed classification provides a framework for understanding and diagnosing demodicosis more effectively.
• Further research, including optimized in vitro/ex vivo models and investigation of bacterial endosymbiosis, is needed to advance treatment and understanding.
• Evidence-based treatment strategies for demodicosis require further development and validation.