Prevalence of Ocular Demodex spp. in Patients with Chronic Uveitis Under Immunosuppressive Treatment

Abstract

This study aimed to evaluate the prevalence of Demodex infestation in patients with chronic uveitis receiving immunosuppressive and/or anti-TNF therapy and to compare the findings with those of a healthy control group. This cross-sectional study included 93 participants (34 uveitis patients and 59 controls). Uveitis was classified according to the Standardization of Uveitis Nomenclature criteria. Demodex was assessed by eyelash epilation followed by masked light microscopic examination and parasite presence and density were recorded. Group comparisons were performed using the chi-square or Fisher’s exact test, with statistical significance set at p<0.05. The groups were comparable in terms of age and sex (p>0.05). The prevalence of Demodex was 11.8% in the uveitis group and 18.6% in the control group, with no significant difference (p=0.52). No association was found between Demodex positivity and the use of anti-TNF agents, methotrexate, azathioprine, or corticosteroids (all p>0.05). Parasite density in positive cases was low to moderate (mean 1.92 ± 1.16; median 2). The lower prevalence observed in the uveitis group may be related to the frequent use of topical corticosteroids, which could suppress local ocular surface inflammation and limit colonization. In conclusion, Demodex prevalence was not increased in patients receiving immunosuppressive or anti-TNF therapy. Further large-scale prospective studies are needed to clarify the relationship between immune modulation, the ocular surface microenvironment, and Demodex infestation.

Keywords

• Ectoparasites
• parasite density
• eyelid microbiota
• ocular microbiota
• Demodex

Ethical Statement

The study was approved by the Malatya Turgut Özal University Health Sciences Scientific Research Ethics Committee (No: 149, 2025).

İmmünosupresif Tedavi Alan Kronik Üveitli Hastalarda Oküler Demodex spp. Prevalansı

Abstract

Bu çalışmada, immünosupresif ve/veya anti-TNF tedavi alan kronik üveitli hastalarda Demodex infestasyonu prevalansının değerlendirilmesi ve sağlıklı kontrol grubu ile karşılaştırılması amaçlandı. Bu kesitsel çalışmaya 34 üveit hastası ve 59 sağlıklı birey olmak üzere toplam 93 katılımcı dahil edildi. Üveit tanısı Standardization of Uveitis Nomenclature (SUN) kriterlerine göre konuldu. Demodex varlığı kirpik epilasyonu sonrası maskeli ışık mikroskobisi ile değerlendirildi ve parazit varlığı ile yoğunluğu kaydedildi. Gruplar arası karşılaştırmalar ki-kare veya Fisher kesin testi ile yapıldı ve istatistiksel anlamlılık p<0.05 olarak kabul edildi. Gruplar yaş ve cinsiyet açısından benzerdi (p>0.05). Demodex prevalansı üveit grubunda %11.8, kontrol grubunda %18.6 olarak saptandı ve aradaki fark istatistiksel olarak anlamlı değildi (p=0.52). Demodex pozitifliği ile anti-TNF ajanlar, metotreksat, azatioprin veya kortikosteroid kullanımı arasında anlamlı ilişki bulunmadı (tüm p>0.05). Pozitif olgularda parazit yoğunluğu düşük-orta düzeydeydi (ortalama 1.92 ± 1.16; medyan 2). Üveit grubunda gözlenen daha düşük prevalansın, topikal kortikosteroidlerin lokal oküler yüzey inflamasyonunu baskılayarak kolonizasyonu sınırlaması ile ilişkili olabileceği düşünüldü. Sonuç olarak, immünosupresif veya anti-TNF tedavi alan hastalarda Demodex prevalansında artış saptanmadı. İmmün modülasyon, oküler yüzey mikroçevresi ve Demodex infestasyonu arasındaki ilişkinin aydınlatılması için daha geniş örneklemli prospektif çalışmalara ihtiyaç vardır.

Keywords

• Ectoparasites
• parasite density
• eyelid microbiota
• ocular microbiota
• Demodex

Ethical Statement

Bu çalışma, Malatya Turgut Özal Üniversitesi Sağlık Bilimleri Bilimsel Araştırma Etik Kurulu tarafından onaylanmıştır (No: 149, 2025).

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