Prevalence of Demodex folliculorum infection in patients referred to the Dermatology Clinic of Imam Reza Hospital in Tehran in 2019
Prevalence of Demodex folliculorum infection in patients referred to the Dermatology Clinic of Imam Reza Hospital in Tehran in 2019
Mohammad Hossein Hajali,1Hamidreza Karbalaei-Musa,2Mohamad Mohsen Homayouni ,3,*
1. Student research committee, AJA University of Medical Sciences, Tehran, Iran 2. Student research committee, AJA University of Medical Sciences, Tehran, Iran 3. Department of Parasitology and Mycology, School of Medicine, AJA University of Medical Sciences, Tehran, Iran
Introduction: One type of external human parasite is worm-shaped scabies called Demodex. Demodex folliculorum and Demodex brevis live in the hair follicles and sebaceous glands of human skin and various mammals, respectively. The mentioned infection should be studied from various clinical and epidemiological aspects in Iran. Therefore, this study was designed and conducted to investigate the frequency of D. folliculorum infection in patients referred to the Dermatology Clinic of Imam Reza Hospital in Tehran.
Methods: Patients with symptoms and skin lesions such as rosacea, skin redness, itching, burning, scaling, and pustules were selected as the study group. After obtaining written informed consent from the subjects and providing the necessary explanations, the research questionnaire was completed to provide background information including age, education, employment status, history of skin diseases, and marital status. To test for Demodex contamination, surface skin chips were prepared, and the samples were taken to the laboratory for testing. Some of the skin chips were placed on a clean microscope slide and clarified by adding a drop of 10% potash solution to one slide and a lactophenol solution to the other. After placing the other slide on top of the sample slide, microscopic observation was performed using objective lenses with magnifications of 10, 4, and 40 times. Demodex-positive cases were photographed at the prepared magnifications and identified by comparing the morphological features and parameters described in the valid sources.
Results: In this study, 100 patients referred to the Dermatology Clinic of Imam Reza Hospital in Tehran with clinical suspicion of infection as diagnosed by a dermatologist, were randomly included in the study. The mean age (standard deviation) of the patients was 26.81 (7.23) years. Regarding gender, 57% of the patients were female and 43% were male. The highest level of education was masters and bachelors (48%) and most of the patients were students and employees. Overall, 10% of patients had a history of skin disease (eczema/hives/fungal infection) and 7% of patients had taken antibiotics in the previous two months. In addition, 3% of patients had an underlying disease (blood pressure/CVA/diabetes). The most common skin manifestations were acne (85%), rosacea (11%) and blepharitis (4%). On examination, Demodex was positive in 6 cases (6%), with 4 cases of mild and 2 cases of moderate involvement. This study investigated the frequency distribution of Demodex infection in patients according to sex, age, education level, skin manifestations, history of skin disease, underlying disease, history of antibiotic use, marital status, and occupation. Among these, only the relationship between Demodex infection and history of skin disease was statistically significant, such that half of the infected patients had a history of skin disease.
Conclusion: The current study showed that compared with other studies, the prevalence of D. folliculorum infection is much lower and is about 6% in patients with suspicious symptoms, and on the other hand, according to the current study, infection with this parasite is only related to the positive history of skin disease and no significant relationship with other variables was observed.