Examination of the density of demodex mites in chronic spontaneous urticaria patients

Aim: Chronic spontaneous urticaria (CSU) is a dermatologic disease that lasts longer than 6 weeks, generally has no specific cause, and manifests with itchy plaques that can seriously impair the quality of life, sometimes with angioedema, and sometimes with only angioedema. In the medical literature, many parasitic infestations have been associated with chronic spontaneous urticaria, and a decrease in the severity of urticaria has been observed with the treatment of these parasitic diseases. Various demodex species live on the skin of mammals as commersal or parasitic. Approximately, 150 species have been described under the demodex genus. There are two types of demodex mites that live on human skin, and recently, the increase in the number of these mites has been shown to be associated with various diseases, especially with rosacea. In this study, we investigated, for the first time whether excessive proliferation of Demodex mites constitutes a risk factor for CSU. Material and Methods: Between September 20, 2021 and May 20, 2022, 100 patients with Chronic Urticaria disease and 50 volunteer control group individuals were included in the study at the Department of Dermatology and Venereal Diseases in Ankara City Hospital. Our study was planned as a prospective case-control study. In both the patient and control groups, if more than 5 organisms were observed in a 1cm area obtained through a standard superficial skin biopsy using cyanoacrylate adhesive, it was considered as increased Demodex density in individuals. The null hypothesis (H0) of our study was defined as 'There is no difference in cheek Demodex density between groups with and without chronic urticaria. Apart from Demodex, the parameters of IgE, TPO, CRP, Hg between the two groups and the mentioned parameters within the groups with increased or not increased Demodex were tested for significant differences. Results: Among the 100 participants in the study, increased Demodex density was found in 21 (21%) individuals' cheeks, whereas in the control group, increased Demodex density was found in 7 (14%) individuals. This difference between the two groups did not reach statistical significance, and our H0 hypothesis could not be rejected (p = 0.3). However, statistically significant differences were found in IgE, TPO, and CRP levels between the two groups, consistent with the medical literature (p <0.05). When comparing the number of individuals with increased Demodex on the cheeks to those without increased Demodex within the patient group, a statistically significant increase in IgE levels was found among individuals carrying Demodex. This difference, identified in our study, is reported for the first time according to the current known medical literature. Conclusion: Although the proportion of patients with increased Demodex density among CU patients was found to be higher compared to the control group in this study, the difference did not reach statistical significance. Despite the increased proportion of patients with increased Demodex density in CU patients, having a higher ratio compared to non-increased cases, our findings did not reach statistical significance. The observation that CU patients with an increased level of Demodex might develop higher levels of IgE could suggest an activation of the immune system's Th2 pathway by Demodex mites. Studies on the nature of the immune response developed against Demodex are limited in the medical literature. Further studies with a larger number of patients and controls are needed in this field.