Assessment of Demodex folliculorum density in psoriasis

Background and Aim : The two Demodex species Demodex folliculorum and Demodex brevis are common obligatory parasites of the pilosebaceous units in human beings. Demodex folliculorum is usually found in the infundibulum of hair follicle and Demodex brevis in the sebaceous glands and ducts. Psoriasis is an autoimmune diseases. Immunocompromised patients with acquired immunodeficiency syndrome developed facial lesions of demodicidosis. Since immunosuppressive are also frequently used for inflammatory or autoimmune skin diseases, we aimed to determine the number of Demodex mites.Methods : This study included ۵۰ patients (۱۰ male, ۴۰ female; mean age ۶۱_۲۰ years) who were admitted to the Dermatology Clinic and were treated with immunosuppressive therapies for psoriasis. The control group consisted of ۵۰ healthy subjects (۱۷ male, ۳۳ female; mean age ۷۱_ ۱۵ years). Direct microscopic examination was done from ۱ cm۲ of facial skin sebum. Some references consider the density of more than five mites per cm۲ as a pathogenic criterion.Results : Demodex mite sampling was positive in ۳۵ patients (۷۰%) and ۱۲ controls (۱۲%). The average of Demodex mite density in patients with psoriasis was ۲۳.۶۶ Demodex test was positive in ۶ men (۶۰%) and ۲۹ women (۷۲.۵%) in psoriasis.Conclusion : Although Demodex mites might be seen in healthy people, density remains low. They become pathogenic when they multiply and reach to the density in skin. However factors affecting the density of Demodex mites are still not known exactly. Some local or systemic factors may induce the proliferation of mites. Immune deficiency was suggested to be the possible cause of overgrowth of mites.

کلیدواژه ها:

Demodex mite ، psoriasis ، autoimmune