The effects of sebum configuration on Demodex spp. density

Abstract

Background/aim: Demodex spp. are ectoparasites living in the pilosebaceous units, which feed on the host's sebum and cellular proteins. The protective barrier of the skin consists of sebum secretion, moisture, and the acid mantle. In this study, we aimed to determine the effects of skin sebum, moisture, pH levels, and sebum configuration on Demodex spp. density Materials and methods: Forty-five patients who had demodicosis were enrolled in the study group, while the control group consisted of 40 subjects without demodicosis. Body fat percentage, serum triglyceride and cholesterol levels, skin sebum, moisture, and pH levels were measured. Demodex spp. density was determined with a standardized skin surface biopsy. Sebum samples were taken from the forehead and a high-performance thin-layer chromatography (HPTLC) method was performed on these samples. Subsequently, densitometric analyses were applied to the HPTLC plates.Results: Demodex spp. were found on the cheeks and lived in an alkali environment. Skin sebum and moisture levels were low in all groups. The skin pH levels and cholesterol ester in the sebum configuration were determined to be significantly higher in the group with demodicosis. Conclusion:We suggest that Demodex spp. may use cholesterol ester in the sebum as nutriment. In other words, cholesterol ester may be a suitable growth medium for the proliferation of Demodex spp.

The effect of skin moisture,pH, and temperature on the density ofDemodex folliculorumandDemodex brevis(Acari: Demodicidae) in students and staff of the Erzincan University, Turkey

“…In our study, 58.9% of the participants with skin moisture less than 30%, 54.3% of with the skin moisture of 30–50%, and 50% of those having skin moisture higher than 50% are infested; however, the differences were not significant. In another study conducted in Turkey, it was found that the sebum and moisture quantities in the demodicosis group were lower than that of the control group, but the difference was also not significant . Participants with a skin pH of 5.1–6.5 were more infested than those with a pH of 4–5; however, the differences were not significant.…”

“…Participants with a skin pH of 5.1–6.5 were more infested than those with a pH of 4–5; however, the differences were not significant. Demirdag et al . reported that skin pH levels were significantly higher in the group with demodicosis.…”

“…Using the standard superficial skin biopsy (SSSB) method, samples were collected from each participant from either the left cheek or right cheek region, which are known to be one of the areas where Demodex mites are most prevalent . A single sample was taken from each participant.…”

“…Most of the published studies stress the prevalence of Demodex ; however, the average number of mites per cm 2 has not been well‐emphasized. In addition, there are only a few studies regarding the influence of skin moisture, pH, and temperature on the prevalence of Demodex …”

Prevalence and Density of Demodex folliculorum and Demodex brevis (Acari: Demodicidae) in Erzincan Province

“…Bununla birlikte cildin nem, pH ve sıcaklığı ile Demodex spp. arasındaki ilişkiye yönelik çok az sayıda çalışma mevcuttur (9)(10)(11)(12) Demodex spp. nin yüz bölgelerindeki dağılımına bakıldığında, enfestasyonun en fazla yanakta olduğu (toplam 1692 tane; ortalama 10,4/cm 2 ), bunu sırasıyla nazolabiyal (toplam 652 tane; ortalama 7,2/cm 2 ) ve çene (toplam 510 tane; ortalama 6,6/cm 2 ) bölgesinin izlediği görüldü.…”