The Incidence of Demodex folliculorum in the Combination of Allergic Rhinitis and Diabetes Mellitus

Background: Demodex mites are permanent ectoparasites of human pilosebaceous unit. They mainly infect skin of the face and scalp. Many studies have shown higher density of the ectoparasites in diseased inflammatory skin than in normal skin. The aim of this study was to determine the frequency of Demodex folliculorum (DF) in treatment-resistant patients with the combination of allergic rhinitis (AR) and diabetes mellitus (DM). Method: This study was conducted in 2014-2017. It included 92 patients aged 18-70 years who presented at the Ear, Nose and Throat (ENT) and Endocrinology Polyclinics of Mustafa Kemal University Medical Faculty Hospital, Turkey. An age and gender matched control group was formed of 30 healthy individuals. To determine the presence of DF, a few eyelashes were taken from eyelids in both groups. Then samples were examined under a light microscope. Results: DF positivity was determined in 44 (47.8%) of the 92 patients and in 1 (3.3%) of the 30 control group subjects. In the patient group, DF positivity was evaluated as present in 14 (43.7%) of the DM patients, in 12 (40%) of the AR patients and in 18 (60%) of the AR+DM patients. Statistically significant DF incidence was found in all three patient groups compared to the control group (P=0.001). The incidence in AR + DM group was not different from other patient groups. Conclusion: DM, AR, advanced age and obesity had prepared the environment for Demodex infestations. This issue should be considered especially in treatment of patients with AR+DM.