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Updated: Jun 28, 2025
The Goeckerman Regimen for the Treatment of Moderate to Severe Psoriasis
Published on: July 11, 2013
Biologic therapy increases Demodex density in psoriasis patients
Hasan Aksoy1, Sümeyye Altıntaş Kakşi1, Öykü Gönüllü1
1Department of Dermatology, Istanbul Medeniyet University Prof. Dr. Suleyman Yalcin City Hospital, İstanbul, Turkey.
Background:
Demodex density is known to increase in various immunosuppressive conditions. The relationship between biologic therapy and Demodex density remains unknown. We aimed to investigate whether the density of Demodex mites is higher in psoriasis patients treated with biologic agents compared to treatment-naive or topically treated patients.
Methods:
A cross-sectional study was conducted, comparing psoriasis patients receiving biologic therapy (n = 34) with controls (n = 33). Demodex density was assessed using the standardized skin surface biopsy technique (SSSB). Statistical analysis was performed to compare the densities and prevalence of demodicosis between the two groups.
Results:
Demodex density was significantly higher in the biologic therapy group compared to the control group on the right cheek (7.29 vs. 0.12/cm2; P = 0.001), left cheek (8.15 vs. 0.24/cm2; P = 0.002), and whole face (average of all four regions: 5.50 vs. 0.80/cm2; P = 0.001). The prevalence of demodicosis was significantly higher in the biologic therapy group on the forehead (35.3% vs. 12.1%; P = 0.043), right cheek (41.2% vs. 0%; P < 0.001), and left cheek (44.1% vs. 0%; P < 0.001). The frequency of cases with demodicosis in at least one localization was higher in the biological therapy group compared to the control group (61.8% vs. 15.2%; P < 0.001).
Conclusions:
Psoriasis patients receiving biologic therapy had a higher Demodex density and prevalence of demodicosis compared to controls. Biologics may lead to an increase in Demodex density by blocking specific cytokines, such as interleukin-17 and tumor necrosis factor-α, which play a role in immunity against Demodex. Further research is needed to explore the impact of different biological agents on Demodex density.
Insights
Biologic therapy for psoriasis significantly increases Demodex mite density and the prevalence of demodicosis. This suggests biologics may impact the immune response to Demodex, warranting further investigation into specific agents.
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.
