Is Demodex folliculorum an aetiological factor in seborrhoeic dermatitis?

The Association Between Acne Vulgaris, Acne Vulgaris with Nonspecific Facial Dermatitis, and Demodex Mite Presence

Background

Demodex mites can lead to various skin disorders, from non-specific dermatitis to conditions that mimic other diseases, making it challenging to diagnose accurately. Additionally, it has been reported that Demodex mites can cause skin conditions such as perioral dermatitis, pustular folliculitis, pityriasis folliculorum, blepharitis, and rosacea. Due to conflicting studies, there is a debate regarding the link between Demodex mites and acne vulgaris. This study aims to determine the prevalence of Demodex mites on the faces of individuals with acne vulgaris, acne with nonspecific facial dermatitis, and healthy facial skin to clarify the association.

Materials and Methods

This observational case-control study involved 120 participants aged 18-37: 40 individuals with acne vulgaris only, 40 with acne and nonspecific facial dermatitis, and 40 healthy controls. The same dermatologist examined and diagnosed all participants to ensure accuracy before being grouped. The Standardized Skin Surface Biopsy (SSSB) method was used to detect Demodex mites in all three study groups. Furthermore, additional samples were collected randomly from acne lesions using the Superficial Needle Scraping (SNS) method in the two acne groups.

Results

The study found no significant difference in Demodex prevalence and high Demodex density rate between patients with only acne vulgaris and the control group (p>0.05). However, acne patients with nonspecific facial dermatitis had a higher rate of Demodex prevalence and high Demodex density rate than the only acne vulgaris and control group (p<0.05). The clinical symptoms of nonspecific facial dermatitis in acne patients strongly associated with Demodex mites are patchy red, dry, scaly skin, roughness, insect bite-like papules, and flushing.

Conclusion

Demodex prevalence and high Demodex density rate are not associated with acne vulgaris. Still, it is associated with acne and nonspecific facial dermatitis, particularly in patients with patchy redness, dry, scaly skin, roughness, insect bite-like papules, and flushing.

Evaluation of the effect of 577-nm pro-yellow laser on demodex intensity

The skin disease of the pilosebaceous unit created by demodex mites is called demodicosis. Recently, it has been brought to the agenda that laser therapies can be effective in reducing the intensity of demodex parasite. With this study, we aimed to evaluate the effect of pro-yellow laser applied to the face on the intensity of demodex parasite. Twenty-five patients who had referred to the dermatology polyclinic with a complaint of rash on the face and who had been given proyellow laser therapy during the past year were included in the study. Average pre-laser therapy demodex number per cm² was 3.9 ± 5.0, while average post-therapy demodex number per cm² was 2.6 ± 4.9 (p = .117). The 577-nm pro-yellow laser caused a change in demodex density. We found that the number of demodex following laser therapy decreased in some patients, while it increased in some others.

Demodex folliculorum infestations in common facial dermatoses: acne vulgaris, rosacea, seborrheic dermatitis

Background

Demodex mites are found on the skin of many healthy individuals. Demodex mites in high densities are considered to play a pathogenic role.

Objective

To investigate the association between Demodex infestation and the three most common facial dermatoses: acne vulgaris, rosacea and seborrheic dermatitis.

Methods

This prospective, observational case-control study included 127 patients (43 with acne vulgaris, 43 with rosacea and 41 with seborrheic dermatitis) and 77 healthy controls. The presence of demodicosis was evaluated by standardized skin surface biopsy in both the patient and control groups.

Results

In terms of gender and age, no significant difference was found between the patients and controls (p > 0.05). Demodex infestation rates were significantly higher in patients than in controls (p = 0.001). Demodex infestation rates were significantly higher in the rosacea group than acne vulgaris and seborrheic dermatitis groups and controls (p = 0.001; p = 0.024; p = 0.001, respectively). Demodex infestation was found to be significantly higher in the acne vulgaris and seborrheic dermatitis groups than in controls (p = 0.001 and p = 0.001, respectively). No difference was observed between the acne vulgaris and seborrheic dermatitis groups in terms of demodicosis (p = 0.294).

Study limitations

Small sample size is a limitation of the study. The lack of an objective scoring system in the diagnosis of Demodex infestation is another limitation.

Conclusion

The findings of the present study emphasize that acne vulgaris, rosacea and seborrheic dermatitis are significantly associated with Demodex infestation. Standardized skin surface biopsy is a practical tool in the determination of Demodex infestation.

Erythematotelangiectatic rosacea may be associated with a subclinical stage of demodicosis: a case-control study

BACKGROUND

Facial densities of Demodex mites have been observed to be greater in patients with demodicosis and papulopustular rosacea than in healthy control patients. In patients with erythematotelangiectatic rosacea (ETR), this density has been observed to be similar to or greater than that of healthy controls. Erythema and telangiectasia, characteristics of ETR, are often observed among patients with pityriasis folliculorum, a discreet demodicosis, suggesting a possible link between these conditions.

OBJECTIVES

To compare the facial Demodex densities of patients with clinical ETR and patients with healthy skin, demodicosis, rosacea with papulopustules, and other facial dermatoses.

METHODS

In this retrospective study, we recorded Demodex densities measured using two consecutive standardized skin surface biopsies (SSSB1 and SSSB2) in 23 patients with ETR, 20 healthy control patients, 590 patients with demodicosis, 254 with rosacea with papulopustules and 180 with other facial dermatoses.

RESULTS

Patients with ETR had higher Demodex densities (D cm^-2 ) than did the healthy controls (mean ± SEM; SSSB1: 15·7 ± 6·3 vs. 1·8 ± 1·1 D cm^-2 , P = 0·042; SSSB2: 38·0 ± 13·7 vs. 5·1 ± 2·1 D cm^-2 , P = 0·026) and patients with other dermatoses (SSSB1: 0·4 ± 0·1 D cm^-2 , P = 0·004; SSSB2: 1·3 ± 0·3 D cm^-2 , P = 0·004), but lower densities than patients with demodicosis (SSSB1: 82·7 ± 4·2 D cm^-2 , P = 0·008; SSSB2: 172·2 ± 7·7 D cm^-2 , P = 0·001) or rosacea with papulopustules (SSSB1: 86·6 ± 7·3 D cm^-2 , P = 0·027; SSSB2: 197·0 ± 12·1 D cm^-2 , P = 0·002).

CONCLUSIONS

ETR may be associated with nonvisible Demodex proliferation, possibly corresponding to a subclinical stage of demodicosis. Dermatologists should be aware of this potential association and look for subclinical demodicosis in patients with ETR, so that topical acaricidal treatment can be offered if Demodex density is high.

The rapid effect of pulsed dye laser on demodex density of facial skin

BACKGROUND

Recently, treatment with acaricides, which is aimed at reducing excessive proliferation of demodex mites, has gained popularity due to its providing a significant improvement in the symptoms of diseases, such as rosacea, seborrhoeic dermatitis, and perioral dermatitis. The effect of IPL on demodex mites was reported in skin biopsy specimens in three patients; however, to the best of our knowledge, no study exists to date, which evaluates the effect of pulsed dye laser (PDL) on demodex density (Dd) in larger patient group. We aim here in to observe the Dd before and after PDL therapy with two different skin biopsy techniques.

MATERIAL AND METHODS

Thirty-one patients diagnosed with rosacea were included in the study who received PDL treatment. Dds which were measured by using both the SSSB (standardized skin surface biopsy) and CTM (cellophane tape method) techniques before and after 3 weeks of PDL therapy were evaluated.

RESULTS AND DISCUSSION

The Dd of patients before PDL treatment was 13.0 (interquartile range (IQR): 5.0-28.0) and after 3 weeks of PDL treatment it was 6.0 (IQR: 3.0-12.0) with SSSB. After PDL treatment, the Dd was significantly lower than pretreatment the Dd (p = 0.002). The present study shows that PDL significantly reduced Dd in facial skin with one session.

Staphylococcus aureus is the most common bacterial agent of the skin flora of patients with seborrheic dermatitis

Background

Seborrheic dermatitis is an inflammatory skin disease that affects 1–3% of the general population. The Malassezia species has been implicated as the main causative agent; however, the bacterial flora of the skin may also play role in the etiopathogenesis. Therefore, we investigated the most common bacterial agent of the skin flora of patients with seborrheic dermatitis.

Materials and Methods

Fifty-one patients with seborrheic dermatitis and 50 healthy individuals are included in this study. Sterile cotton swabs were rubbed on the scalp of the participants for bacterial culture. Colonial morphology was identified with gram stain and catalase test.

Results

Staphylococcus aureus was isolated from 25 (49%) patients with seborrheic dermatitis and 10 (20%) healthy individuals within the control group. Coagulase-negative staphylococci were isolated from 24 (47.1%) patients with seborrheic dermatitis and 17 (34%) healthy individuals within the control group. Diphtheroids were present in 2 (3.9%) patients and 1 (2%) subject within the control group. Gram-negative bacilli were present only in 1 (2%) patient. Hemolytic streptococci and bacilli were identified in 1 (2%) subject from each group. Colonization of coagulase-negative staphylococci, diphtheroids, gram-negative bacilli, hemolytic streptococci, and bacillus did not differ between patients and healthy controls. However, S. aureus colonization was significantly more common in patients with seborrheic dermatitis than in healthy controls.

Conclusion

Within this study we revealed that S. aureus colonization was significantly higher among the patients. Therefore, we propose that, in addition to the Malassezia species, S. aureus may play a role in the etiopathogenesis of seborrheic dermatitis.

Demodex spp. as a possible aetiopathogenic factor of acne and relation with acne severity and type

Introduction

Acne is a very common skin disease in adolescents and young adults, but it also affects adults. However, its aetiology is not yet fully understood. Demodex appears to be associated with multiple skin disorders, but controversy persists. Some reports indicate a connection between acne vulgaris and demodicosis.

Aim

To confirm the association between Demodex infestation and acne vulgaris.

Material and methods

A total of 108 patients were enrolled in the acne group. Acne severity was calculated as GASS and acne type (adolescent and post adolescent) was recorded. An age-sex matched healthy control group comprising 65 individuals were included in the study. Dermatological examinations were performed and an SSSB was used to determine the presence of Demodex.

Results

In our study, Demodex positivity was seen in 46 (42.6%) patients in the acne group and 8 (12.3%) in the control group; this difference was statistically significant (p < 0.001). A multivariate Backward Step-By-Step Logistic Regression analysis identified the most effective factors for acne development such as Demodex positivity (OR = 5.565, 95% CI: 2.384–12.99 and p < 0.001) and age under 25 years (OR = 2.3 and 95% CI: 1.183–4.473 and p = 0.014). Alcohol consumption was related to Demodex positivity (p = 0.019) in post adolescent acne.

Conclusions

Our study is the first one to evaluate acne severity, acne type and the relationship to Demodex prevalence. We suggest that Demodex infestation should be considered when the classical therapies are ineffective especially in cases of post adolescent acne.

The Demodex mites and their relation with seborrheic and atopic Dermatitis

OBJECTIVE

To determine the prevalence of seborrhoeic dermatitis (SD) and atopic dermatitis (AD) between the Demodex folliculorum (D. folliculorum) positive and D. folliculorum negative patients and to investigate any possible relationship between the D. folliculorum mites and the presence of SD and AD.

METHODS

In this cross sectional study, authors collected samples from the skin around the nasal tip of 180 randomized patients who reffered to Amir Al-Momenin Hospital dermatology clinic for skin erythema, scaling and pruritis, to examine the precence of demodicosis (D. folliculorum) infestation under optical microscope. Then authors assessed the prevalence of SD and AD between the D. folliculorum positive and D. folliculorum negative patients. Finally, data analysis using SPSS software and Chi-square test were performed.

RESULTS

Our study showed no significant association between the demodicosis (D. folliculorum) and SD (P=0.68) and AD (P=0.70) prevalence.

CONCLUSIONS

According to the result of this study, the eradication of Demodex mites probably is not effective to reduces the prevalence of both dermatitis. However further investigation on a larger scale in a case-control study in this area is recommended.

Potential role of microorganisms in the pathogenesis of rosacea

Rosacea is a skin condition of abnormal inflammation and vascular dysfunction. The active contribution of a microbial agent in the development or progression of rosacea continues to be debated. Research supports the presence of commensal Demodex folliculorum mites at increased density in the skin and associates Helicobacter pylori infection of the gut with rosacea. Fewer studies implicate Staphylococcus epidermidis, Chlamydophila pneumoniae, and the Demodex-associated bacteria Bacillus oleronius. No research, however, provides a mechanism by which colonization by a microorganism translates to manifestation of the condition. Prevailing and emerging principles in the biology of the microbiome and the pathophysiology of rosacea may help to reconcile these lingering questions. Here the microorganisms implicated in rosacea are reviewed and the reaction of the microbiome to inflammation and to changes in microenvironments and macroenvironments are discussed to explain potential roles for microorganisms in rosacea pathophysiology.

Facial dermatosis associated with Demodex: a case-control study

Demodex has been considered to be related with multiple skin disorders, but controversy persists. In this case-control study, a survey was conducted with 860 dermatosis patients aged 12 to 84 years in Xi'an, China to identify the association between facial dermatosis and Demodex. Amongst the patients, 539 suffered from facial dermatosis and 321 suffered from non-facial dermatosis. Demodex mites were sampled and examined using the skin pressurization method. Multivariate regression analysis was applied to analyze the association between facial dermatosis and Demodex infestation, and to identify the risk factors of Demodex infestation. The results showed that total detection rate of Demodex was 43.0%. Patients aged above 30 years had higher odds of Demodex infestation than those under 30 years. Compared to patients with neutral skin, patients with mixed, oily, or dry skin were more likely to be infested with Demodex (odds ratios (ORs) were 2.5, 2.4, and 1.6, respectively). Moreover, Demodex infestation was found to be statistically associated with rosacea (OR=8.1), steroid-induced dermatitis (OR=2.7), seborrheic dermatitis (OR=2.2), and primary irritation dermatitis (OR=2.1). In particular, ORs calculated from the severe infestation (≥5 mites/cm(2)) rate were significantly higher than those of the total rate. Therefore, we concluded that Demodex is associated with rosacea, steroid-induced dermatitis, seborrheic dermatitis, and primary irritation dermatitis. The rate of severe infestation is found to be more correlated with various dermatosis than the total infestation rate. The risk factors of Demodex infestation, age, and skin types were identified. Our study also suggested that good hygiene practice might reduce the chances of demodicosis and Demodex infestation.