Facial dermatosis associated with Demodex: a case-control study

Guo

Meng

et al. 2011

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Abstract:To identify sociodemographic characteristics and risk factor of Demodex infestation, 756 students aged 13-22 years in Xi'an, China were sampled for the school-based cross-sectional study. Demodex was examined using the cellophane tape method (CTP). The results showed that the total detection rate of Demodex was 67.6%. Logistic regression analysis revealed that five variables (gender, residence, sharing sanitary ware, frequency of face-wash per day, and use of facial cleanser) were found to be uncorrelated with Demodex infestation, whereas three variables (age, skin type, and skin disease) were found to be independent correlates. Students aged over 18 years had 22.1 times higher odds of Demodex infestation compared to those under 16 years and students aged 16-18 years also had 2.1 times higher odds compared to those aged 13-15 years. Odds of having a Demodex infestation for oily or mixed skin were 2.1 times those for dry or neutral skin. Students with a facial skin disease had 3.0 times higher odds of being infested with Demodex compared to those without. The inception rate of students with facial dermatoses increased in parallel with increasing mite count. The inception rates were 21.3%, 40.7%, 59.2%, and 67.7% in the negative, mild, moderate, and severe infestation groups, respectively (χ 2 =60.6, P<0.001). Specifically, the amount of infested mites and inception rate of acne vulgaris were positively correlated (R 2 =0.57, moderate infestation odds ratio (OR)=7.1, severe infestation OR=10.3). It was concluded that Demodex prevalence increases with age, and Demodex presents in nearly all adult human. Sebaceous hyperplasia with oily or mixed skin seems to favour Demodex proliferation. Demodex infestation could be associated with acne vulgaris. The CTP is a good sampling method for studies of Demodex prevalence.

Section: Discussionsupporting

confidence: 87%

Sociodemographic characteristics and risk factor analysis of Demodex infestation (Acari: Demodicidae)

Guo

Meng

et al. 2011

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“…Only if excess Demodex was detected could we associate the lesions with Demodex. In the present study, although we included and analyzed 63 papers about the association between Demodex infestation and acne vulgaris, only 3 English papers (Baysal et al, 1997;Zhao et al, 2011a;2011b) matched the inclusion criteria. Also only one study we could searched used SSB method (Okyay et al, 2006), and it did not match the inclusion criteria.…”

Section: Discussionmentioning

confidence: 99%

“…According to the inclusion and exclusion criteria mentioned above, 60 Chinese papers covering 25 provinces/municipalities and only 3 English papers (Baysal et al, 1997;Zhao et al, 2011a;2011b) were eligible, which consisted of 42 130 subjects in total including students and residents, aged from 1 to 78 years. Most of the subjects were university and middle school students who were prone to acne vulgaris in the age of 11 to 25 years.…”

Section: Overall Informationmentioning

confidence: 99%

A meta-analysis of association between acne vulgaris and Demodex infestation

et al. 2012

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Until now, etiology of acne vulgaris is still uncertain. Although clinicians usually deny the association between Demodex infestation and acne vulgaris, it has been proved in some clinical practices. To confirm the association between Demodex infestation and acne vulgaris, a meta-analysis was conducted. Predefined selection criteria were applied to search all published papers that analyzed the association between Demodex infestation and acne vulgaris (January 1950 to August 2011) in ISI Web of Knowledge, MEDLINE, and China National Knowledge Infrastructure (CNKI) databases. A meta-analysis was performed to calculate odds ratios (ORs) and 95% confidence intervals (CIs) based on fixed effects models or random effects models. We enrolled the 60 Chinese and 3 English papers in this meta-analysis, which covered Turkey and 25 different provinces/municipalities in China and 42 130 participants including students and residents, aged from 1 to 78 years. The pooled OR in random effects models is 2.80 (95% CI, 2.34-3.36). Stability is robust according to sensitivity analysis. The fail-safe number is 18 477, suggesting that at least 18 477 articles with negative conclusions would be needed to reverse the conclusion that acne vulgaris was related to Demodex infestation. So the effect of publication bias was insignificant and could be ignored. It was concluded that acne vulgaris is associated with Demodex infestation. This indicates that when regular treatments for acne vulgaris are ineffective, examination of Demodex mites and necessary acaricidal therapies should be considered.

“…Up to now, 140 species or subspecies have been identified, infesting the hair follicles, sebaceous glands, meibomian glands, and internal organs of 11 orders of mammals such as human, dog, sheep, cat, pig, and (Izdebska, 2010;Mederle et al, 2010), goat demodicidosis (Smith, 1961;Xu et al, 2009), livestock demodicidosis (Chakrabarti and Pradhan, 1985), and human demodicidosis (Ayres and Anderson, 1932;Ayres and Ayres, 1961;Forton and Seys, 1993;Forton et al, 2005;Zhao et al, 2010;2011a;2011c;2012c). However, the pathogenesis of demodicidosis is still uncertain, and there are no effective prevention measures.…”

Section: Introductionmentioning

confidence: 99%

Cloning and sequence analysis of chitin synthase gene fragments of Demodex mites

Wang

et al. 2012

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To our knowledge, few reports on Demodex studied at the molecular level are available at present. In this study our group, for the first time, cloned, sequenced and analyzed the chitin synthase (CHS) Phylogenetic trees based on maximum parsimony (MP) and maximum likelihood (ML) methods shared the same clusters, according with the traditional classification. Two open reading frames (ORFs) were identified in each CHS gene sequenced, and their corresponding amino acid sequences were located at the catalytic domain. The relatively conserved sequences could be deduced to be a CHS class A gene, which is associated with chitin synthesis in the integument of Demodex mites.