Increased Demodex Mite Density Observed in Psoriasis Patients on Biologic Therapy: Study

A study study published in the International Journal of Dermatology uncovered a significant increase in Demodex mite density among the patients with psoriasis who are undergoing biologic therapy when compared to the individuals who are treatment-naive or only receive topical treatments. This pivotal finding highlights a potential side effect of biologic treatments which are commonly used to manage severe cases of psoriasis.

The study was conducted as a cross-sectional analysis and included 34 psoriasis patients on biologic therapy and 33 control patients either new to treatment or using only topical therapies. The research team utilized the standardized skin surface biopsy technique (SSSB) to measure Demodex densities on various facial areas including the cheeks and forehead.

The results revealed a sharp difference in Demodex density between the two groups, particularly on the right cheek where densities were 7.29 mites per cm2 in the biologic therapy group when compared to just 0.12 mites per cm2 in the control group. Similar patterns were observed on the left cheek and across the whole face with biologic therapy patients who showed significantly higher mite densities.

The prevalence of demodicosis which is a condition caused by high Demodex density, was notably higher among the individuals who were receiving biologic treatments. The forehead and cheeks of these patients showed elevated rates of demodicosis when compared to controls. Also, 44.1% of patients on biologics showed high mite densities on the left cheek when compared to none in the control group.

The benefits of these findings suggest that while biologic agents are effective in treating the inflammatory symptoms of psoriasis, they might also impair the ability of the skin to control Demodex mite populations. This could be due to the inhibition of specific cytokines like interleukin-17 and tumor necrosis factor-alpha that play crucial roles in the immune response of body against these mites.

The outcomes emphasized the importance of this discovery, while biologic therapies offer significant benefits in controlling psoriasis symptoms, this study observed an increase in Demodex density that may contribute to skin discomfort or aggravate other dermatological issues. Further research is imperative to fully understand the impact of different biological agents on Demodex populations. Overall, the patients who receive these treatments should be monitored for signs of increased Demodex density and demodicosis, which could potentially be managed with appropriate skin care and medical interventions.

Reference:

Aksoy, H., Altıntaş Kakşi, S., Gönüllü, Ö., Aslan Kayıran, M., & Erdemir, V. A. (2024). Biologic therapy increases Demodex density in psoriasis patients. In International Journal of Dermatology. Wiley. https://doi.org/10.1111/ijd.17161