Biologic therapy increases Demodex density in psoriasis patients.

Area of Science:

• Dermatology
• Immunology
• Microbiology

Background:

• Demodex mite density is known to increase in immunosuppressive conditions.
• The impact of biologic therapy on Demodex density in psoriasis patients was previously unknown.

Purpose of the Study:

• To investigate if Demodex mite density is higher in psoriasis patients treated with biologic agents compared to treatment-naive or topically treated patients.

Main Methods:

• A cross-sectional study compared 34 psoriasis patients on biologic therapy with 33 controls.
• Demodex density was assessed using the standardized skin surface biopsy technique (SSSB).
• Statistical analysis compared Demodex densities and demodicosis prevalence between groups.

Main Results:

• Significantly higher Demodex density was observed in the biologic therapy group across the cheeks and whole face (P < 0.001).
• The prevalence of demodicosis was significantly higher in the biologic group on the forehead, right cheek, and left cheek (P < 0.05).
• Overall, 61.8% of biologic patients had demodicosis compared to 15.2% in controls (P < 0.001).

Conclusions:

• Psoriasis patients on biologic therapy exhibit increased Demodex density and demodicosis prevalence.
• Biologics might elevate Demodex density by inhibiting cytokines like IL-17 and TNF-α, which are crucial for immunity against Demodex.
• Further research is needed to understand the effects of different biologic agents on Demodex density.