Demodex Density Research Articles

Role of Demodex mite infestation in rosacea: A systematic review and meta-analysis

The reported prevalence and degrees of Demodex mite infestation in rosacea vary widely. We sought to conduct an evidence-based meta-analysis of the prevalence and degrees of Demodex mite infestation in patients with rosacea. Systematic literature review and meta-analysis were conducted. Odds ratios for prevalence of infestation and standardized mean difference (SMD) for Demodex density in patients with rosacea were pooled. Subgroup analysis for type of rosacea, control group, and sampling and examination methods were also performed. Twenty-three case-control studies included 1513 patients with rosacea. Compared with the control patients, patients with rosacea were more likely to be infested by Demodex mites [odds ratio, 9.039; 95% confidence interval (CI), 4.827-16.925] and had significantly higher Demodex density (SMD, 1.617; 95% CI, 1.090-2.145). Both erythematotelangiectatic rosacea (SMD, 2.686; 95% CI, 1.256-4.116) and papulopustular rosacea (SMD, 2.804; 95% CI, 1.464-4.145) had significantly higher Demodex density than did healthy control patients. Interstudy variability was high, and a causal relationship could not be established by case-control studies. Patients with rosacea had significantly higher prevalence and degrees of Demodex mite infestation than did control patients. Demodex mites may play a role in both erythematotelangiectatic rosacea and papulopustular rosacea.

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

This study aimed to determine the prevalence and density of Demodex folliculorum and D. brevis in Erzincan Province and the association between Demodex spp. and skin moisture, pH, and temperature. The study included total 300 healthy participants without dermatological ailments and residing in Erzincan Province. Moisture, pH, and temperature of the cheek were measured, and the presence of mite was determined in samples from the cheek, nasolabial, and chin region using the standard superficial skin biopsy technique. The prevalence and density of D. folliculorum and D. brevis were found to be 61.3% (mean 14.3/cm2) and 23.3% (mean 3.2/cm2), respectively, in healthy participants. Infestation by Demodex spp. was greater in the cheek (mean 10.4/cm2), followed by the nasolabial region (mean 7.2/cm2) and chin (mean 6.6/cm2), respectively (p<0.001). The prevalence and density of Demodex spp. were greater in those with dry skin (mean 11.6/cm2), pH of 5.5-7.0 (mean 11.2/cm2), and temperature of 20-23°C (mean 13.1/cm2). Males, with aged >60 years, with lower educational status, and who were single were significantly more infested with Demodex spp. Demodex mites are very prevalent in healthy individuals with different skin moisture, skin pH, skin temperature, and demographic characteristics. This may be taken into consideration when epidemiological and clinical studies are conducted on patients having different dermatological ailments.

Two Consecutive Standardized Skin Surface Biopsies: An Improved Sampling Method to Evaluate Demodex Density as a Diagnostic Tool for Rosacea and Demodicosis.

Diagnosing papulopustular rosacea is not always straightforward; no specific diagnostic test is currently available. A high density of Demodex mites is consistently observed in this condition. This retrospective study assesses an improved method for evaluating Demodex density among 1,044 patients presenting to our dermatology practice. The skin was cleaned with ether and Demodex densities were measured in 2 consecutive standardized skin surface biopsies taken from the same site. Mean densities in patients with rosacea and demodicosis were much higher than those in healthy controls and patients with other facial dermatoses. The optimal cut-off values for the 2 biopsies were combined and the resultant criterion (presence of a first biopsy density < 5 Demodex/cm2 or a second biopsy density < 10 Demodex/cm2) enabled confirmation of a diagnosis of rosacea or demodicosis with a sensitivity of 98.7% and specificity of 95.5%, making this a valuable diagnostic tool for dermatologists in routine clinical practice.

Assessment of demodex presence in acne-like rash associated with cetuximab

Context: Cetuximab is an epidermal growth factor receptor inhibitor. It is frequently used in the treatment of solid tumors. However, it has a high potential to cause acne-like rash. Demodex mites, which are known to increase in number in immunosuppressive circumstances, are closely related to the acneiform lesions.Objective: The aim of this study is to evaluate the presence of demodex mites in acne-like rash that appears under the treatment of Cetuximab.Methods: We reviewed the medical records of patients who applied to our clinic with cetuximab induced papulopustular rashes between November 2014 and March 2016. Demodex sampling was performed by standardized skin surface biopsy (SSSB) in a total of 11 patients (eight males and three females). Infestation was defined as at least 5 living parasites/cm2 of skin.Results: Upon the SSSB examination in 10 out of the 11 patients, no demodex mites were detected. Demodex mites were found in only one of the patients. This patient, in whom two dead Demodex folliculorums were found through facial sampling, was also regarded as negative since his demodex density was under the threshold limit value.Conclusion: In this study, it has been concluded that acne-like rash that develops under the treatment of cetuximab is not related to the presence of demodex mites. Papulopustular eruptions that develop under cetuximab treatment should not be directly correlated with the presence of demodex; first SSSB and demodex presence should be evaluated.

Efficacy and safety of permethrin 5% topical gel vs. placebo for rosacea: a double-blind randomized controlled clinical trial.

Rosacea is a chronic, multifactorial, dermatological condition. Increased density of Demodex folliculorum mites in the skin of rosacea patients suggests a possible role for these mites in the pathophysiology of rosacea. To evaluate the effects of permethrin 5% topical gel vs. placebo on Demodex density (Dd) and clinical presentations of rosacea patients, and also to further refine the quantitative assessment of Dd in the non-invasive standard skin surface biopsy (SSSB). Twenty patients with bilateral papulopustular rosacea and ≥5 mites/cm2 were enrolled in the study. Participants and physicians were blinded to the group assignments. Each patient applied permethrin on one side and placebo on the other side of the face twice daily for 12 weeks. SSSB and photography and Rosacea Clinical Scorecard of the National Rosacea Society were used to assess the patients at the baseline, 2nd, 5th, 8th, and 12th weeks for both sides of the face. Causality and severity of adverse drug reactions (ADRs) were assessed by WHO Scale and Hartwig Scale, respectively. Dd was not significantly different between the two groups at the baseline. In both groups, Dd significantly decreased after 12 weeks compared to the baseline. At the end of the 12th week, the Dd in the permethrin group was significantly lower than the placebo group. Severity of the clinical presentations decreased in both groups at the end of week 12 in comparison to the baseline, particularly in the permethrin group. ADRs were all mild and in most cases unlikely related to permethrin. Permethrin 5% gel can significantly reduce the Dd and severity of presentations in rosacea patients and can be a safe and effective option in the management of this chronic disorder. This new SSSB technique offers an easy, quick, inexpensive, and non-invasive sampling method proper for quantitative assessment of Dd.

The Frequency of Demodex Spp in Depression Patients

Objective: Demodex spp., usually located on the human skin, including the face and eyelashes, is a mandatory ectoparasite. The aim of this study was to evaluate the prevalence and factors affecting Demodex spp. in patients with depression. Materials and Methods: In this study, 63 depressed patients and 63 healthy controls were evaluated. To collect samples for analysis, a drop of glue containing cyanoacrylate was put on a lamella and the lamella was pressed on the certain areas of the face (forehead, cheeks, nose, and chin) for about a minute. Then it was carefully removed and the density of Demodex spp. in a cm2 was counted under a microscope. For the diagnosis, the presence of five or more Demodex spp. in a cm2 was considered to be positive. Results: In 23.8% of depressed patients (n=15) and in 9.5% of the control group (n=6), Demodex spp. was detected in the facial area. The presence of Demodex spp. in the facial area of depressed patients was significantly higher compared to the control group. When CGI severity scores of patients and the relationship between the severity of depression and the presence of Demodex spp. were compared, no significant difference was detected. Conclusion: Depression may be a risk factor for the infection of Demodex parasites because of impaired immune system as well as reduction of self-care and hygiene of the person. For the itchy lesions on the face of depressed patients, Demodex spp. infestation should also be taken into consideration.

Reflectance confocal microscopy vs. standardized skin surface biopsy for measuring the density of Demodex mites

Reflectance confocal microscopy (RCM) has been recently shown to be effective for measuring the Demodex mite density. To compare and demonstrate the advantages and disadvantages of standardized skin surface biopsy (SSSB) and RCM for measuring the density of Demodex mites. Forty-eight patients (30 female, 18 male) and 47 healthy controls (30 female, 17 male) were enrolled in the study. The patients diagnoses were pityriasis folliculorum (n=40), papulopustulary rosecea (n=7) and erythema-telengiectatic rosacea (n=1). The area with the most intense erythema on the right cheek was selected for imaging with RCM (VivaScope 3000) and SSSB. Forty-two patients demonstrated high Demodex density [(Dd)>5mites/cm(2) ] with SSSB (85.7%). RCM identified demodicosis in 48 patients (100%). The mean Dd measured with RCM (409.8±209.2) was significantly higher than SSSB (15.33±18.1) (P<0.001). In the patients, RCM demonstrated the mean number of mites 40.90±20.9 and 4.11±6.4 in the controls per 10mm(2) area. The corresponding mean number of 2.63±0.77 mites was detected in the infested follicles per area of view compared to a mean of 0.77±0.98 mites in the infested follicles in the controls (P<0.001). Reflectance confocal microscopy is a fast, direct and noninvasive method for Demodex-associated diseases and it is superior to SSSB for Demodex mite detection.

Increased Density of Demodex folliculorum Mites in Pregnancies with Gestational Diabetes

Objective: To investigate the presence of Demodex in patients with gestational diabetes and the impact of glucose regulation on Demodex density in gestational diabetes. Subjects and Methods: The study population consisted of 33 patients with gestational diabetes and 30 pregnant women without gestational diabetes (control group). The age, parity, gestational age, and BMI of the study group were recorded and the patients were divided into 2 groups, i.e. those with regulated and unregulated glucose levels, according to their postprandial 1st- and 2nd-hour glucose values. A standardized skin surface biopsy method was used to determine if patients had Demodex folliculorum infestation (>5 mites/cm² of skin). Results: Patients with gestational diabetes had a statistically significantly higher Demodex density compared to the control group (24.2 vs. 3.3%; p < 0.001). Furthermore, a significantly higher proportion of gestational diabetes patients with unregulated glucose levels had a higher Demodex density compared to those in the regulated subgroup (6/19 vs. 2/14; p = 0.001). Conclusion: Our study revealed that the Demodex density was increased in gestational diabetes patients. Further, poor glucose regulation could be the mechanism responsible for the increased Demodex density in gestational diabetes patients with unregulated glucose levels compared to those with regulated glucose levels.

Density of Demodex folliculorum in Patients Receiving Epidermal Growth Factor Receptor Inhibitors

Background: Rosacea-like papulopustular eruptions (rash) are considered the most frequent toxicities associated with the use of inhibitors of the epidermal growth factor receptor (EGFR). Recently, evidence has been accumulating of infectious complications in patients suffering from these adverse effects. Objective: We sought to analyze the density of Demodex folliculorum (DF) in cutaneous lesions of patients presenting with EGFR-inhibitor (EGFRI)-induced rashes. Methods: This is a retrospective study of 19 adult patients presenting with EGFRI rashes. Patients were reviewed for the density of DF (Demodex density, Dd; mites per square centimeter) by standardized skin surface biopsy. Results: In our patient collective the mean Dd of 4.7/cm² significantly exceeded the mean Dd reported for the healthy adult population (Dd = 0.7/cm²). Limitations: The retrospective nature of the study. Conclusions: EGFRI patients have an increased susceptibility to DF colonization or infection, respectively. Our results support the recent concept that EGFRI may induce an impairment of antimicrobial defense mechanisms.

A study of the pathogenesis of Rosacea: how angiogenesis and mast cells may participate in a complex multifactorial process

In the present study we evaluated, in involved and clinically uninvolved skin of Rosacea, microvessels density (MVD) and total vascular area (TVA) in addition to multiple morphologic characteristics of microvessels and also mast cells (MCs) number. We examined also the relationship between angiogenesis, MCs number and disease clinicopathological data. The study included 69 patients with Rosacea. A skin biopsy with a 4-mm punch was performed from clinically involved skin in each case. In nine randomly selected patients, facial biopsy specimens were obtained from both involved and clinically uninvolved skin. Histological sections, immunostained for factor VIII, were evaluated by image analysis for the quantification of MVD, TVA and several morphometric parameters related to the vessel size or shape. MCs detection in the dermis was carried out using the chloracetate esterase method (Fast Blue RR) in parafin sections. Serum antibodies against H.pylori were detected. Statistically important differences concerning the factors of angiogenesis between lesional and clinically non-lesional skin were demonstrated. A statistical important correlation was found also between high vascular density, PPR clinical type and the presence of ocular manifestations. MVD or TVA showed no correlation with the degree of solar elastosis or inflammation and with the Demodex density as well. However, high MVD values were found to correlate with granuloma formation in the dermis. MCs number were significantly greater in lesional compared to clinically non-lesional skin. Statistical significance was shown between MCs density and disease duration. However, no correlation between MCs number and blood vessel density was found. Angiogenesis seems to play an important role in the pathogenesis especially of the more severe clinical form of Rosacea. MCs seem to participate in evolution to disease chronicity by contributing to inflammation, angiogenesis and tissue fibrosis.

Demodicosis and rosacea: Epidemiology and significance in daily dermatologic practice

Demodicoses are thought to be rare, occurring mainly for patients with immunosuppression. We sought to demonstrate the high frequency of demodicoses and the overlapping with papulopustular rosacea (PPR) . We conducted a prospective epidemiologic study among 10 dermatologists. High Demodex density (Dd) was confirmed by standardized skin surface biopsy. In all, 4372 diagnoses, in which 115 were demodicoses, were collected among 3213 patients. Demodicosis was the 9th most frequent diagnosis (13th new). Each dermatologist observed an average of 2.4 demodicoses a week (1.2 new). The proportion of demodicoses varied greatly according to the dermatologist. The general status was good in 110 patients; only 3 had known immunodeficiency. The most frequent symptoms were follicular scales (71%) and telangiectasia (63%). The mean Dd was higher in pityriasis folliculorum (m = 61 D/cm 2 ) than in PPR (m = 36 D/cm 2 ; P = .04); 42 patients with PPR had a high Dd, 6 had a low Dd. Demodicoses are frequent and occur among patients who are immunocompetent. PPR with normal Dd are rare.

Demodex folliculorum in development of dermatitis rosaceiformis steroidica and rosacea-related diseases

During investigations with rosacea, demodex folliculits and dermatitis rosaceiformis steroidica patients some interesting questions appeared. Why Demodex is found in several situations where the sebum secretion is low ? Why infestations with Demodex is increasing with age and reach up to 100% in elderly people, 5 when sebum excretion rate reach a maximum between the age of 16 and 40, and thereafter declined in both sexes, particularly in females? The higher Demodex density observed in papulopustular stage of rosacea, demodex folliculitis and dermatitis rosaceiformis steroidica suggest, although it does not prove, that the mite plays a role in formations of papules and pustules what is common in some of the stages of all these diseases.

Density of Demodex folliculorum in rosacea: a case-control study using standardized skin-surface biopsy.

A standardized skin-surface biopsy (1 cm2) of the check was performed in 49 patients with rosacea [13 with erythemato-telangiectatic rosacea (ETR), three with squamous rosacea (SR), 33 with papulopustular rosacea (PPR)], and 45 controls. A mean density of 0.7 Demodex folliculorum/cm2 was found in controls, 98% of whom had less than five Demodex/cm2. When all clinical types of rosacea were considered collectively, the density of Demodex was significantly higher in patients with rosacea than in controls (mean = 10.8/cm2; P < 0.001). When the various clinical types of rosacea were considered separately, Demodex density was statistically significantly higher than in controls only in the PPR patients (mean = 12.8/cm2; P < 0.001). The same type of comparison was also made for three other groups of subjects--patients with isolated inflammatory papules (n = 4), rhinophyma (n = 3), and HIV infection (n = 21), respectively: in these groups, the Demodex density did not differ significantly from controls. The present study demonstrates a high density of D. folliculorum in PPR, and supports its pathogenic role in the papulopustular phase of rosacea. The study suggests that standardized surface biopsy could be a useful diagnostic tool for PPR, with a 98% specificity when Demodex density is higher than 5/cm2.