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Updated: Mar 10, 2026
In Vivo Confocal Microscopy: A Standard Operating Procedure for the Detection of Demodex Mites at the Eyelid Margin
Published on: July 3, 2025
The effects of sebum configuration on Demodex spp. density
Hatice Gamze Demirdağ1, Hamdi Özcan2, Şule Gürsoy3
1Department of Dermatology, Ankara Oncology Training and Research Hospital, Ankara, Turkey.
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.
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