The Pathogenic Role of Demodex Mites in Rosacea: A Potential Therapeutic Target Already in Erythematotelangiectatic Rosacea?

Which factors influence Demodex mite density in standardized superficial skin biopsy in patients with rosacea? A prospective cross-sectional analysis

Rosacea is a chronic cutaneous disease that manifests with facial erythema, telangiectasia, papules and pustules on the central face. Although the pathogenesis is not well established, rosacea appears to have a close relationship with Demodex mites. The aim of the study was to elucidate the factors influencing Demodex mite density by standardized superficial skin biopsy (SSSB) in patients with rosacea. This prospective, cross-sectional study included 200 patients with rosacea. Clinical characteristics of the patients were recorded and SSSB was used to measure Demodex density (Dd). If Dd was < 5 D/cm2 in the first SSSB, SSSB was repeated 4 more times to avoid false negative results. Of 200 patients, 152 (76%) were females and 48 (24%) males with a mean age of 43.47 ± 11.87 years. Ninety-nine patients (49.5%) had erythematotelangiectatic (ETR) and 101 patients (50.5%) had papulopustular (PPR) subtype of rosacea. Among 200 patients, the ratio of cumulative positive results of the consecutive SSSBs were as follows: 1st SSSB = 125 (62.5%), 2nd SSSB = 155 (77.5%), 3rd SSSB = 170 (85%), 4th SSSB = 173 (86.5%) and 5th SSSB = 174 (87%). The ratio of detecting Demodex infestation in the first SSSB was significantly lower in patients with PPR (55/101, 54.5%) than in patients with ETR (70/99, 70.7%). Median total Demodex mite density and D. folliculorum density were significantly higher in the ETR group than in the PPR group. There was a statistically significant relationship between density of Demodex tails in dermoscopy and positive/negative results of Demodex infestation in SSSB. As a conclusion, Demodex mite density by SSSB was influenced by various factors such as subtypes of rosacea, types of Demodex species, and dermoscopic findings.

Rosacea in Older Adults and Pharmacologic Treatments

Rosacea is a chronic inflammatory skin condition that is often more severe in older patients. The main clinical features are erythema, telangiectasia, and inflammatory lesions of the face. The pathogenesis of this condition is not fully understood but certainly multifaceted. Immune and inflammatory dysregulation, genetics, neurogenic dysregulation, microbiome dysbiosis, and systemic disease have all been implicated in rosacea pathogenesis. As we better understand the various pathways that lead to rosacea, we acknowledge that the different symptoms may have unique underlying triggers and mechanisms. Aging also impacts rosacea diagnosis and treatment. Older adults have more severe rosacea symptoms while also having more sensitive and fragile skin than younger patients; therefore, rosacea treatments for older patients require a balance between delivering adequate potency while also minimizing skin irritation and other adverse effects. Until recently, rosacea diagnoses were based on concrete subtypes that did not necessarily capture each patient's manifestation of rosacea. There is now an emphasis on more personalized phenotype-based diagnoses and treatments, which allows for more emphasis on treating individual symptoms and accounting for the unique characteristics of older patients. Centrofacial erythema is best treated with brimonidine and oxymetazoline, while phymatous change and telangiectasia are best treated with surgery and laser ablation. Treatment for rosacea papules and pustules ranges from topicals, such as azelaic acid, ivermectin, metronidazole, minocycline, and encapsulated benzoyl peroxide, to systemics, such as doxycycline and isotretinoin. It is important to understand these treatments in relation to adverse effects and drug interactions that may specifically arise in older populations to provide optimal care. As we advance in understanding rosacea's pathogenesis and adopt personalized phenotype-based approaches, optimizing care for older patients becomes crucial. Continued research into novel treatments is essential to address their unique needs.

Rosacea: Pathogenesis and Therapeutic Correlates

Rosacea is a chronic inflammatory condition of which there is no cure. The pathogenesis of rosacea is likely multifactorial, involving genetic and environmental contributions. Current understanding suggests that pro-inflammatory pathways involving cathelicidins and inflammasome complexes are central to rosacea pathogenesis. Common rosacea triggers modulate these pathways in a complex manner, which may contribute to the varying severity and clinical presentations of rosacea. Established and emerging rosacea treatments may owe their efficacy to their ability to target different players in these pro-inflammatory pathways. Improving our molecular understanding of rosacea will guide the development of new therapies and the use of combination therapies.

A Review of the Diagnostic and Therapeutic Gaps in Rosacea Management: Consensus Opinion

Rosacea is a common, chronic inflammatory disease characterized by both fluctuating and fixed heterogeneous signs such as facial erythema, papules/pustules, telangiectasia, acute vasodilation (flushing), and phymatous changes, and symptoms such as cutaneous stinging and burning. The shift to a phenotype-based approach to rosacea management has improved the consistency of recommendations across recent published guidelines. Consistent and thorough guidance for the classification, diagnosis, and management of the disease is difficult, as the mechanisms underlying the development of rosacea are still not completely understood nor universally accepted. Here, we provide a critical review of current published guidance, and gaps in the knowledge and management of rosacea. We present the recently approved microencapsulated benzoyl peroxide as an effective topical treatment option for papulopustular rosacea. Benzoyl peroxide (BPO) has been used in acne management for many years; however, many clinicians perceive treatment of rosacea with any BPO formulation to be counterintuitive because of concerns of potential skin irritation, while the lack of an accepted mechanism of action on rosacea pathophysiology means that others may be hesitant to use BPO as a treatment. Minocycline foam 1.5% is also an option for the treatment of inflammatory lesions in rosacea, with a decreased risk of systemic adverse events compared with oral minocycline.

Investigation of skincare habits and possible rosacea triggers of patients with rosacea: A prospective case-control study

OBJECTIVE

Skincare is a part of rosacea treatment; patients benefit from complementary dermo-cosmetic care as well as medical treatments. Some skincare habits are known to trigger and exacerbate rosacea, but there are very few epidemiological studies on this matter.

METHODS

A total of 200 people, including 100 patients with rosacea and 100 controls, were included in the study. We questioned the methods used by the participants in daily facial cleansing. Sun and heat exposure, makeup habits, the history of the use of topical steroids, and outdoor working status were noted. A dermoscopic examination, a non-invasive and valuable method to evaluate the presence and severity of Demodex, was performed.

RESULTS

We evaluated 30% of our rosacea patients as erythematotelangiectatic rosacea, 13% as papulopustular rosacea, and 57% of our patients had mixed type, which could not be distinguished from one of these subtypes. In the case group, the proportion of people who used daily facial cleansers and daily soaps was lower than in the control group, while the proportion of those who cleaned their face with only water and those who used facial cleansers less frequently was higher (p<0.001). In the case group, while the rate of daily make-up and use of make-up products was lower (p=0.001, p<0.001, respectively), the rate of not wearing make-up was higher (p=0.001). The history of hot bath use was higher in the case group than in the control group (p=0.011). We found a significant relationship between the severity of plaque and dry appearance and the increase in Demodex density (p=0.007, p<0.001, respectively).

CONCLUSION

We recommend that patients with rosacea clean their faces daily with soap or facial cleansers and not take a bath with very hot water. Patients should be evaluated for increased Demodex mites, especially if skin dryness is accompanied.

Demodicosis in a Kunekune pig and molecular characterisation of porcine demodectic mites involved: a case report

BACKGROUND

In January 2021, a female 1-year-old Kunekune was presented at the University Clinic for Swine with severe reduction of the field of vision resulting in prolonged reaction time when targeting barriers, due to moderate to severe thickening of the skin around both orbits also affecting the eyelids.

METHODS

Clinical examination revealed skin hyperplasia, nodular enlargement of the skin pores of the axillar and inguinal region. Ophthalmologists decided to remove parts of the thickened periocular skin, followed by histopathological examination.

RESULTS

Once large amounts of demodectic mites were detected by histopathology, demodicosis could be diagnosed and treatment of the pig was started using sarolaner. Morphological and molecular analyses were performed. Histopathological and parasitological exams led to the aetiological diagnosis of demodicosis in the affected Kunekune pig. Severe skin lesions were revealed to be the consequence of an infestation with Demodex sp. Morphological analyses confirmed the involvement of D. phylloides. Molecular characterization indicated a Demodex species closely related to mites documented in wild boar - most probably D. phylloides for which no explicit sequences are available in GenBank yet. Treatment with sarolaner (2.6 mg/kg) resulted in a substantial regression of skin lesions, already detectable 1 month after first treatment.

CONCLUSIONS

Demodicosis is a very rare disease in pigs that is most probably related to an impaired immune response to the mites. Demodectic mange should be included in the list of differential diagnoses in cases of periocular alterations of the skin of pigs.

Rosacea, microbiome and probiotics: the gut-skin axis

Rosacea is an inflammatory skin disease involving diverse symptoms with a variable clinical progress which can severely impact the patient's quality of life as well as their mental health. The pathophysiological model of rosacea involves an unbalanced immune system predisposed to excessive inflammation, in addition to vascular and nervous alterations, being certain cutaneous microorganisms' triggers of the symptoms onset. The gut-skin axis explains a bidirectional interaction between skin and gut microbiota in some inflammatory skin diseases such as atopic dermatitis, psoriasis, or rosacea. The introduction and consolidation of the next-generation sequencing in recent years has provided unprecedented information about the microbiome. However, the characterization of the gut and skin microbiota and the impact of the gut-skin axis in patients with rosacea has been little explored, in contrast to other inflammatory skin diseases such as atopic dermatitis or psoriasis. Furthermore, the clinical evolution of patients with rosacea is not always adequate and it is common for them to present a sustained symptomatology with frequent flare-ups. In this context, probiotic supplementation could improve the clinical evolution of these patients as happens in other pathologies. Through this review we aim to establish and compile the basics and directions of current knowledge to understand the mechanisms by which the microbiome influences the pathogenesis of rosacea, and how modulation of the skin and gut microbiota could benefit these patients.

Long-term maintenance treatment of rosacea: experts' opinion

BACKGROUND

Rosacea is a chronic inflammatory dermatosis characterized by remissions and flares. Although the rosacea active treatment phase is well established, the long-term maintenance phase is still challenging.

OBJECTIVE

To discuss and make recommendations on how to treat patients during the long-term maintenance phase for the main rosacea phenotypes.

METHODS

A panel of six board-certified Brazilian dermatologists and one American dermatologist gathered to compose a consensus based upon an initial statement on how to treat rosacea during the long-term maintenance phase based on the methodology Nominal Group Technique. The experts discussed each factor based upon an initial statement on how to treat rosacea patients in the long-term maintenance phase. A sequence of comprehensive narrative reviews was performed; a questionnaire preparation about the definition of the maintenance phase and its management was presented; an interpersonal discussion and ranking of the ideas were conducted. Recommendations were made if the specialists had 75% agreement.

RESULTS

The maintenance treatment phase, which starts by achieving IGA 0 or 1 grades at the active phase, should be considered at least during the 9-month period after remission. The recommendations of all treatments target this period. Daily skincare regimen and sunscreen are crucial. Active treatment phase should be recommended if signs or symptoms reappear or worsen.

CONCLUSION

Maintenance phase success depends on patient's adherence to daily skin care, appropriate treatments, continued follow-up with dermatologist, and self-assessment to identify new signs and symptoms indicating disease relapse.

Cloning, sequencing, expression, and purification of aspartic proteases isolated from two human Demodex species

Aspartic proteases (ASPs) are important hydrolases for parasitic invasion of host tissues or cells. This was the first study on Demodex ASP. First, the complete coding sequence (CDS) was amplified, cloned and sequenced. Then, the protein physical and chemical properties was analysed. Finally, the recombinant plasmid, expression and purification system was established. Results showed that the lengths of CDS of Demodex folliculorum and D. brevis were 1161 and 1173 bp, respectively. The molecular weight of the protein was approximately 40 KDa. It contained an aspartic acid residue, a substrate-binding site and signal peptide, yet lacked a transmembrane domain and was located in the membrane or extracellular matrix. The phylogenetic and conserved motif analyses showed that D. folliculorum and D. brevis clustered separately and then formed a single branch, which finally clustered with other Acariformes species. The prokaryotic expression systems for recombinant ASP with His-tag (rASP-His) and GST-tag (rASP-GST) were constructed. The inclusion bodies of rASP-His were renaturated by gradient urea and purified using NI beads, while those of rASP-GST were renaturated by sarkosyl and Triton X-100 and purified using GST beads. Conclusively, the prokaryotic expression and purification system of Demodex rASP was successfully established for further pathogenic mechanism research.

Emerging Medical Therapies in Rosacea: A Narrative Review

Rosacea is a chronic inflammatory disease with a multifactorial pathogenesis. The wide spectrum of clinical phenotypes, including erythema, telangiectasia, inflammatory papules and pustules, and phyma, demand an individualized approach to treatment. This narrative review offers an updated reference for rosacea management by covering the latest developments in both topical and systemic treatments, including data from newly approved therapies, updates to current treatment modalities and ongoing clinical trials. Although use of benzoyl peroxide as a treatment for rosacea has typically been limited due to irritation, the improved tolerability due to microencapsulation of benzoyl peroxide 5% cream provides a new therapeutic option for patients with rosacea. Minocycline foam and topical ivermectin cream add to our armamentarium of treatment options, particularly for inflammatory papules and pustules. Sarecycline has a narrower spectrum of antibacterial activity, which might reduce the development of antibiotic resistance and disruption of the microbiome compared to other oral antibiotics. Brimonidine gel and oxymetazoline cream provide topical options for redness and flushing. There is emerging evidence about the role of hydroxychloroquine and intradermal botulinum toxin A, which may improve rosacea through their effects on mast cells. The clinical trials pipeline includes agents with a variety of mechanisms, including mast cell stabilization, antimicrobial, anti-inflammatory, and vasoconstrictive effects. However, the clinical pipeline for rosacea appears limited, and there remain important unmet needs for patients with more recalcitrant rosacea or phymatous disease. In addition, there is a need for comparative effectiveness studies to identify the highest value treatment approaches for patients with rosacea.

Effectiveness and Safety of Upadacitinib in Combination with Topical Corticosteroids in Adolescent Patients with Moderate-to-Severe Atopic Dermatitis

Purpose

To investigate the therapeutic effectiveness and safety of Janus kinase 1 inhibitor upadacitinib in adolescent patients with atopic dermatitis (AD).

Patients and Methods

This study examined therapeutic effectiveness and safety of upadacitinib for 39 Japanese adolescent patients (aged 12-17 years) diagnosed with moderate-to-severe AD from August 2021 to January 2023. The patients were treated with upadacitinib 15 mg/day plus twice daily topical corticosteroids. Total eczema area and severity index (EASI) or EASI on head and neck, upper limbs, lower limbs, and trunk or for erythema, edema/papulation, excoriation, or lichenification, atopic dermatitis control tool (ADCT), peak pruritus-numerical rating scale (PP-NRS), and laboratory indexes were assessed at weeks 0, 4, and 12 of treatment. Treatment-emergent adverse events were recorded.

Results

Total EASI or EASI on 4 anatomical sites or for 4 rash types, ADCT, and PP-NRS were significantly reduced at week 4 and 12 compared to week 0. The achievement rates at weeks 4 or 12 were 64.1% or 62.5% for EASI 75, 93.5% or 73.1% for ADCT <7-point, and 80.6% or 60% for PP-NRS ≥4-point improvement, respectively, indicating their peak at week 4 and slight decrease at week 12. The percent reduction of EASI for excoriation was higher than that for lichenification or edema/papulation at week 4 or week 12, respectively. The percent reductions of EASI for erythema and edema/papulation on head and neck were lower than those on lower limbs at week 12. Total eosinophil counts (TEC) and IgE reduced at week 4 compared to week 0 while TARC, IgE, TEC, and LDH increased at week 12 compared to week 4.

Conclusion

These results suggest therapeutic effectiveness and tolerability of upadacitinib and support its therapeutic usefulness for adolescent AD patients.

The role of macrophages in rosacea: implications for targeted therapies

Introduction

Rosacea, a widespread chronic skin condition, may be influenced by macrophages, key immune cells in the skin, although their exact role is not yet fully understood. This review delves into the function of macrophages, their potential contribution to rosacea pathogenesis, current treatments, and promising macrophage-targeted therapies. It concludes by identifying knowledge gaps and potential areas for future rosacea research.

Method

Leveraging systematic and narrative literature review techniques, we conducted a comprehensive search of databases such as PubMed, Embase, and Web of Science. Utilizing keywords like "rosacea" and "macrophages", we targeted English articles from the last 5 years (2018-2023). We manually checked reference lists of relevant articles for additional studies. We included only articles emphasizing macrophages' role in rosacea and/or the development of related therapies and published within the specified timeframe.

Results

The systematic search of electronic databases yielded a total of 4,263 articles. After applying the inclusion and exclusion criteria, 156 articles were selected for inclusion in this review. These articles included original research studies, review articles, and clinical trials that focused on the role of macrophages in rosacea and/or the development of macrophage-targeted therapies for the disease. The selected articles provided a comprehensive and up-to-date overview of the current state of research on macrophages in rosacea, including their function in the skin, the potential mechanisms through which they may contribute to rosacea pathogenesis, and the current treatments and therapies available for the disease. Additionally, the articles identified gaps in knowledge regarding the role of macrophages in rosacea and suggested potential areas for future research.

Conclusion

This literature review emphasizes the important role that macrophages, vital immune cells in the skin, may play in the pathogenesis of rosacea, a common chronic inflammatory skin disorder. The selected studies suggest potential mechanisms by which these cells might contribute to rosacea progression, although these mechanisms are not yet fully understood. The studies also spotlight current rosacea treatments and illuminate the promising potential of new macrophage-focused therapies. Despite these insights, significant gaps persist in our understanding of the precise role of macrophages in rosacea. Future research in this area could provide further insights into the pathogenesis of rosacea and contribute to the development of more effective, targeted therapeutic strategies.

A Prospective Randomized Controlled Pilot Study to Assess the Response and Tolerability of Cold Atmospheric Plasma for Rosacea

INTRODUCTION

Rosacea is a common, facial, chronic inflammatory skin disease. Due to its complex pathogenesis, adequate therapy of rosacea can be challenging. An innovative recent therapeutic tool is cold atmospheric plasma (CAP), which is already established in the treatment of chronic wounds and promising in different other skin diseases.

METHODS

In a split-face pilot study we investigated dielectric-barrier-discharged CAP in erythemato-telangiectatic (ETR) and/or papulopustular rosacea (PPR). CAP treatment was applied on lesional skin of a randomized side once daily (90 s/area) for 6 weeks. The other untreated side served as control. Co-primary endpoints were ≥1 improvement of the Investigator Global Assessment (IGA) score on the treated side compared to control and a decline of the Dermatology Life Quality Index (DLQI) after 6 weeks. Secondary endpoints included inflammatory lesion count (papules and pustules), skin redness intensity and erythema size. Adverse events (AEs) were recorded constantly. Additionally, participants were weekly assessed for symptoms, skin condition, trigger factors, skin care, treatment success, and local tolerance parameters. All p values were calculated using the Wilcoxon signed-rank test.

RESULTS

Twelve subjects (ETR, n = 3; ETR and PPR, n = 9) completed the study. DLQI was significantly improved after 6 weeks (p = 0.007). On the CAP-treated side, lesions (p = 0.007) and erythema size (p = 0.041) were significantly reduced compared to the control. IGA (p = 0.2) and skin redness intensity (p = 0.5) did not differ significantly between control and CAP-treated side. No serious AEs occurred and treatment was well tolerated.

CONCLUSION

CAP is a promising new treatment of rosacea, especially for PPR.

Comparison of in vitro Killing Effect of Thai Herbal Essential Oils, Tea Tree Oil, and Metronidazole 0.75% versus Ivermectin 1% on Demodex folliculorum

Background

Abnormal proliferation of Demodex mites causes a skin disorder called demodicosis and has been linked to rosacea. The development of alternative therapy against Demodex mites is currently required. The ability to kill Demodex mites of Thai herbal essential oils has never been explored. This study aimed to study and compare the in vitro killing effect of Thai herbal essential oils, tea tree oil, and metronidazole 0.75% with ivermectin 1% on D. folliculorum.

Materials and Methods

D. folliculorum mites were collected from the wastes of diagnostic standardized skin surface biopsy samples of demodicosis and rosacea patients for the trial. The microscopic evaluation started immediately after the mites were exposed to immersion oil (negative control), Thai herbal essential oils, tea tree oil, metronidazole 0.75%, and ivermectin 1% (positive control). The survival times of ten mites from each test agent were compared.

Results

The efficacy of Thai herbal essential oils and other test agents can be arranged in order as follows: lemongrass oil > sweet basil oil > clove oil > tea tree oil > lesser galangal oil > ginger oil, kaffir lime oil, peppermint oil > citronella oil > galangal oil > cajeput oil > ivermectin 1% > metronidazole 0.75%.

Conclusion

This current study demonstrated the in vitro killing efficacy on D. folliculorum: Thai herbal essential oils, Tea tree oil > ivermectin 1% > metronidazole 0.75%. Thai herbal essential oils have the potential to be an adjuvant or alternative therapy against Demodex mites. Further in vivo studies are necessary to determine the treatment efficacy and side effects.

Gene expression analysis of Canine Demodicosis; A milieu promoting immune tolerance

Canine demodicosis is a common skin disease seen in companion animal practice that results from an overpopulation of the commensal Demodex mite species. Common predisposing factors to the development of canine demodicosis include immunosuppressive diseases, such as neoplasia and hypothyroidism, and administration of immunosuppressive therapies, such as corticosteroids. Despite this, the pathogenesis of development of canine demodicosis remains unclear. Previous studies have implicated a role for increased expression of toll like receptor 2 (TLR2), increased production of interleukin (IL)-10) and T cell exhaustion. Here, we investigate gene expression of formalin fixed paraffin embedded skin samples from twelve cases of canine demodicosis in comparison to twelve healthy controls, using a 770 gene panel (NanoString Canine IO Panel). Results show an increase in the T cell population, specifically Th1 and Treg cells in dogs with demodicosis. In addition, while there is an upregulation of immunosuppressive cytokines such as IL-10 and IL-13, there is also an upregulation of immune check point molecules including PD-1/PD-L1 and CTLA-4. These findings suggest that Demodex spp. mites are modulating the host immune system to their advantage through upregulation of several immune tolerance promoting pathways.

Role of Cutaneous Microbiome in Dermatology

The cutaneous microflora consists of various microorganisms which interact with host epithelial cells and innate and acquired immunity. This microbial milieu and its interaction with host cells prevent the growth of pathogenic organisms and educate host immunity to fight against harmful microorganisms. The microbial composition depends on various intrinsic and extrinsic factors and an imbalance in the cutaneous microflora predisposes the individual to both infectious and non-infectious diseases. Even though probiotics have been extensively studied in various diseases, their efficacy and safety profile are still unclear. A better understanding of the cutaneous microflora is required to develop newer therapeutic targets. In this review, we describe the commensal microbiome and its variation, the current role of the cutaneous microbiome in the pathogenesis of various dermatological diseases, and their therapeutic implications.

Identification and genetic characterisatin of cathepsin L in Demodex

Owing to difficulties in obtaining functional gene sequences, molecular pathogenic mechanisms in Demodex have been understudied. In this study, overlap extension PCR was used to obtain the sequences of cathepsin L (CatL), a pathogenicity-related gene, to provide a foundation for subsequent functional research. Demodex folliculorum and Demodex brevis mites were obtained from the face skin of Chinese individuals, and Demodex canis mites were isolated from the skin lesions of a dog. RNA was extracted and used to synthesise double-stranded cDNA. PCR amplification, cloning, sequencing, and bioinformatics analysis of CatL were performed. CatL gene sequences of 1005, 1008, and 1008 bp were successfully amplified for D. brevis, D. folliculorum, and D. canis, respectively. These sequences showed 99.9 or 100% identity with templates previously obtained by RNA-seq. The Maximum Likelihood (ML) phylogenetic tree showed that D. folliculorum clustered with D. canis first, then with D. brevis, and finally with other Acariformes mite species. The three Demodex species had nine similar motifs to those of Sarcoptes scabies, Dermatophagoides pteronyssinus, and Dermatophagoides farinae, and motifs 10-13 were valuable for identification. CatL proteins of Demodex species were predicted to be approximately 38 kDa, be located in lysosomes, have a signal peptide but no transmembrane region, and have two functional domains, I29 and Pept_C1. However, interspecific differences were observed in secondary and tertiary protein structures. In conclusion, we successfully obtained CatL sequences of three Demodex species by overlap extension PCR, which creates conditions for further pathogenic mechanism studies.

Demodicosis in Different Age Groups and Alternative Treatment Options-A Review

Infestation with Demodex mites is a common occurrence, especially in adults and the elderly. More recent attention has been paid to the presence of Demodex spp. mites in children, even ones without comorbidities. It causes both dermatological and ophthalmological problems. The presence of Demodex spp. is often asymptomatic, thus it is suggested to include parasitological investigation tests in dermatological diagnostics, in addition to bacteriological analysis. Literature reports show that Demodex spp. are related to the pathogenesis of numerous dermatoses, including rosacea or demodicosis gravis, and common eye pathologies reported by patients such as dry eye syndrome or ocular surface inflammatory conditions, such as blepharitis, chalazia, Meibomian gland dysfunction, and keratitis. Treatment of patients is a challenge and is usually prolonged, therefore it is important to carefully diagnose and properly select the therapy regimen for the treatment to be successful, and with minimal side effects, especially for young patients. Apart from the use of essential oils, research is ongoing for new alternative preparations active against Demodex sp. Our review was focused on the analysis of the current literature data on the available agents in the treatment of demodicosis in adults and children.

Characteristics of Rosacea and Similar Diseases in Patients Wearing Face Masks

Introduction

The present study aimed to obtain fundamental data, including climate conditions and Demodex mites, on rosacea and similar diseases in the situation where the wearing of face masks is mandatory due to the coronavirus disease 2019 pandemic.

Methods

We enrolled 86 Japanese patients habitually wearing face masks with rosacea and similar diseases. Disease severity was assessed using the Investigator Global Assessment. The presence of Demodex mites was examined microscopically. Treatment involved acaricidal and antibiotic agents.

Results

The numbers of male and female patients enrolled were 11 and 75, respectively. Among these patients, 85 (98.8%), 57 (66.3%), and 76 (88.4%) had rosacea, rosacea-like dermatitis (RLD), and demodicosis, respectively. The monthly number of patients with rosacea and demodicosis showed two peaks from May to June and in October, during which monthly mean temperature was approximately 20°C (68°F). Improvement rates in rosacea, RLD, and demodicosis were significantly higher when Demodex mites were no longer detected after treatment.

Conclusion

The present results suggest that a season with a mean temperature of approximately 20°C is a risk factor for rosacea and similar diseases in individuals wearing face masks in Japan, and a decrease in Demodex mites is associated with the attenuation of symptoms.

Papulopustular Rosacea Treated With Ivermectin 1% Cream: Remission of the Demodex Mite Infestation Over Time and Evaluation of Clinical Relapses

INTRODUCTION

Topical ivermectin is an anti-inflammatory and anti-Demodex drug for papulopustular rosacea. Rosacea is a relapsing disease and the time between recurrences should be considered alongside efficacy.

OBJECTIVES

The aims of this study were to assess the time of first relapse and relapse rates of Demodex mite infestation and papulopustular rosacea.

METHODS

We conducted a prospective study of subjects affected by different degrees of papulopustular rosacea. Patients that achieved a complete response after treatment were monitored every 4 weeks and up to 32 additional weeks. For each patient, we evaluated recording the time to first relapse and relapse rate of Demodex mite infestation and rosacea.

RESULTS

The overall success rate on Demodex infestation was 87.5% only 12.5% relapse. Ivermectin leads to complete response in 70% of patients. Median time to relapse was 140 days, the mean time was 152 days. The global success rate was 54.76%.

CONCLUSIONS

Topical ivermectin keeps a remission of Demodex infestation and clinical remission for long time. We proposed a twice weekly ivermectin maintenance therapy to reduce recurrences.

Complete mitochondrial genomes of Thyreophagus entomophagus and Acarus siro (Sarcoptiformes: Astigmatina) provide insight into mitogenome features, evolution, and phylogeny among Acaroidea mites

Mites from the Acaroidea (Sarcoptiformes: Astigmatina) are important pests of various stored products, posing potential threats to preserved foods. In addition, mites can cause allergic diseases. Complete mitochondrial genomes (mitogenomes) are valuable resources for different research fields, including comparative genomics, molecular evolutionary analysis, and phylogenetic inference. We sequenced and annotated the complete mitogenomes of Thyreophagus entomophagus and Acarus siro. A comparative analysis was made between mitogenomic sequences from 10 species representing nine genera within Acaroidea. The mitogenomes of T. entomophagus and A. siro contained 37 genes, including 13 protein-coding genes (PCGs), 22 transfer RNAs (tRNAs), two ribosomal RNAs (rRNAs), and one control region. In Acaroidea species, mitogenomes have highly conserved gene size and order, and codon usage. Among Acaroidea mites, most PCGs were found to be under purifying selection, implying that most PCGs might have evolved slowly. Our findings showed that nad4 evolved most rapidly, whereas cox1 and cox3 evolved most slowly. The evolutionary rates of Acaroidea vary considerably across families. In addition, selection analyses were also performed in 23 astigmatid mite species, and the evolutionary rate of the same genes in different superfamilies exhibited large differences. Phylogenetic results are mostly consistent with those identified by previous phylogenetic studies on astigmatid mites. The monophyly of Acaroidea was rejected, and the Suidasiidae and Lardoglyphidae appeared to deviate from the Acaroidea branch. Our research proposed a review of the current Acaroidea classification system.

Development of an animal model for rosacea‑like skin lesions caused by Demodex

To develop an animal model of rosacea-like skin lesions caused by Demodex mites, a suspension of Demodex mites was injected into the skin of Japanese rabbits. The pathology of the skin lesion was assessed using H&E staining after 4 weeks of modeling. The skin lesions observed after 4 weeks were further treated with the recombinant bovine basic fibroblast growth factor (rbFGF) gel. Untreated lesions in the same rabbit were considered as the blank control. Erythema papules were observed in the model rabbit skin and could be observed most clearly in the 2nd week. Lumpy foreign bodies, telangiectasia and granuloma-like structure were observed in the model rabbit in the 1st, 2nd, and 3rd weeks, respectively. An organized granuloma-like structure was observed in the 4th week. The color of the skin lesions became lighter than that of the self-control after 4 weeks of rbFGF treatment. In conclusion, the model of Demodex-induced rosacea-like skin lesions can be developed through intradermal injection of suspension of Demodex mites into Japanese rabbits. The model can mimic the phenotype of skin lesions and histopathological manifestations in the Demodex mite-positive patient with rosacea.

Comparison of in vitro Killing Effect of N, N-Diethyl-Meta-Toluamide (DEET) versus Permethrin on Demodex folliculorum

Background

There is no single effective treatment for demodicosis; successful treatment requires a multimodal approach. Relapse or recurrence of demodicosis is relatively high, making the therapy challenging. Several reports have documented the successful treatment of demodicosis with acaricidal agents, which aimed at reducing the excessive number of Demodex mites and improving the patients' symptoms. Reports of irritation and resistance to topical acaricidal agents have led to the search for effective alternative treatments.

Materials and Methods

A total of 100 standardized skin surface biopsy (SSSB) biopsy slides from 100 patients with demodicosis were randomly divided into five groups, each with 20 slides exposed to immersion oil, N, N-diethyl-meta-toluamide (DEET) 5%, 10%, 20%, and permethrin 1%, respectively. The microscopic evaluation started immediately after the test agents exposed the mites. The survival time (ST) was defined as the interval between the first exposure of Demodex folliculorum to the test agents to the time the movements ceased.

Results

The differences between the median ST of DEET 5% (44 min), 10% (22 min), and 20% (14 min) were significant when compared to the negative control group (240 min) with p<0.001, <0.001, <0.001, respectively. While the median ST of permethrin 1% (42 min) was not significantly different from the median ST of DEET 5% (p=0.7395).

Conclusion

This study demonstrated the dose-related acaricidal effect of DEET on D. folliculorum. The survival times of DEET 5%, 10%, and 20% were significantly shorter than the negative control (immersion oil). DEET 5% had a comparable in vitro killing effect as permethrin 1%. Further in vivo studies are necessary to determine the clinical efficacy in patients with demodicosis.

Rosacea and Dry Eye Disease

Ocular rosacea is a chronic potentially sight-threatening inflammatory condition, which can occur in approximately 20% of patients without skin involvement. However, an accurate diagnosis of ocular rosacea has not been defined yet due to its rather nonspecific symptoms and clinical findings. Therefore, this article updates the current recommendations for diagnosis and treatment of ocular rosacea and the previously published consensus recommendations from the ROSCO expert panel on the management of rosacea.

The comparative in vitro killing activity of tea tree oil versus permethrin on Demodex folliculorum of rosacea patients

BACKGROUND

Demodex mites have been implicated in several cutaneous disorders compelling the research efforts for effective anti-Demodex therapy.

OBJECTIVE

Compare the survival time (ST) of Demodex folliculorum exposed to six different concentrations of tea tree oil (TTO) versus a positive control (permethrin 5%) and a negative control (immersion oil) group.

MATERIALS AND METHODS

The wastes of rosacea patients' standardized superficial skin biopsy samples were recruited for the trial. The primary outcome measure of this study was the survival time, defined as the period between the exposure of study agents to the complete cessation of Demodex movements.

RESULTS

All differences between the mean survival times of 2.5% (54.0 ± 6.1), 5% (39.0 ± 3.9), 10% (22.0 ± 2.5), 25% (13.0 ± 2.5), 50% (7.8 ± 0.6), and 100% TTO (3.3 ± 1.3) were significant (p < 0.05). The ST of the negative control group was 196.0 ± 23.6 min. The ST of permethrin 5% was 12.5 ± 1.9 that did not show a statistically significant difference from the ST of TTO 25% (p = 0.628).

CONCLUSION

The survival times of the six different TTO groups confirmed a dose-related pattern, all of which had survival times shorter than the negative control (immersion oil). TTO 25% had comparable efficacy to the positive control agent (permethrin 5%).

Rosacea: Treatment targets based on new physiopathology data

Over the past 15 years, numerous clinical, epidemiological and physiopathological articles have been published on rosacea. There is now increasing evidence that rosacea is an inflammatory disease characterised by abnormal innate immune response, major vascular changes, and increased colonisation by Demodex mites, along with a genetic predisposition and multiple external aggravating factors. It is thus possible to define treatment targets and possible treatments: 1) permanent vascular changes (medical and instrumental treatments); 2) flushing (betablockers, botulinum toxin); 3) innate immunity (antibiotics, nonspecific antioxidants and anti-inflammatory molecules); 4) a neurovascular component (analgesics, antidepressants); 5) Demodex (antiparasitic drugs); 6) microbiome; 7) skin barrier impairment (cosmetics and certain systemic drugs); 8) sebaceous glands (isotretinoin, surgery); 9) environmental factors (alcohol, coffee, UV exposure). Treatment recommendations are now available in many countries and benefit from the new phenotypic approach to rosacea, in which every sign or symptom is considered separately rather than having to deal with overlapping subtypes. Since the 2000s, many good quality clinical trials have been published in the field of rosacea and many others are still ongoing. Rosacea is a complex disease involving many different mechanisms and with numerous possible treatments, but there are still some important unmet needs with regard to optimal care.

Demodex folliculorum (Trombidiformes: Demodicidae) and Demodex brevis Prevalence in an Extreme Environment of Chile

The prevalence of mites of the genus Demodex and their associations with host age, gender, workplace, and comorbid skin and ocular conditions were studied in participants in Antofagasta, Chile, which is in a region with an extreme environment. We examined 680 participants aged 18-88 yr using standardized surface skin biopsies. Among them, Demodex had a prevalence of 13.5 % (95% confidence interval, 10.88-16.17). A slightly higher prevalence was observed in males (51.1%; 95% confidence interval, 40.9-61.3; nonsignificant) and participants in the 69-88 yr age group (50.0%; 95% confidence interval, 23.8-76.2; P < 0.05). Regarding the species involved, Demodex folliculorum was found in 89.1% (CI 82.7-95.5) of cases, while D. brevis was found in the remaining 10.9% of cases. A higher prevalence (25.0% CI 16.1-33.91) was observed in participants who worked indoors in generally enclosed and dust-rich environments (such as theaters, libraries, and administrative offices). There was also a strong association between Demodex prevalence and conjunctival hyperemia, with 35.9% (95% confidence interval, 9.1-35; OR 17.9) of the Demodex positive participants having this pathology compared to 10.3% of the noninfested participants. In summary, the prevalence of Demodex in Antofagasta, Chile (13.5%) was toward the lower end of the range reported among other regions around the world. Environmental factors such as exposure to the sun (including ultraviolet rays) or environmental pollution may affect the mites. In addition, Demodex genetics (related to virulence) and the ocular or skin microbiota may positively or negatively influence infestation and pathology.

Thymic Stromal Lymphopoietin in Cutaneous Immune-Mediated Diseases

Thymic stromal lymphopoietin (TSLP) was initially demonstrated to be critical in regulating inflammatory responses among various allergic disorders (such as atopic dermatitis, food allergy, and asthma). Although two isoforms (short form and long form) of TSLP have been demonstrated in human tissues, the long form of TSLP (lfTSLP) is strongly implicated in the pathogenesis of allergies and cutaneous immune-mediated diseases. The immunomodulatory activity of lfTSLP varies widely, driving T helper (Th) cells polarizing Th2 and Th17 immune responses and inducing itch. Moreover, lfTSLP is closely associated with skin fibrosis, epidermal hyperplasia, angiogenesis, and homeostatic tolerogenic regulations. This review highlights significant progress from experimental and clinical studies on lfTSLP in cutaneous immune-mediated diseases (atopic dermatitis, psoriasis, bullous pemphigoid, systemic sclerosis, chronic spontaneous urticaria, Behçet’s disease, vitiligo, rosacea, systemic lupus erythematosus, and alopecia areata). We also offer original insights into the pleiotropic properties of the cytokine TSLP in various pathophysiological conditions, with significant clinical implications of TSLP-targeted therapies for immune-mediated skin diseases in the future.

Demodex infestation as a cause of sensitive skin in a dermatology outpatient clinic

BACKGROUND

Sensitive skin is subjective cutaneous hyperreactivity to environmental factors. Demodicosis is a skin disorder caused by Demodex mites. There may be a link between demodicosis and sensitive skin.

AIM

This study aimed to examine facial Demodex mites density and other factors associated with sensitive skin in patients.

METHODS AND METHODS

A total of 349 randomly selected patients presented to the dermatology department. The research data were collected using a questionnaire form that included the participants' sociodemographic and lifestyle characteristics, a sensitive skin questionnaire, the Dermatology Life Quality Index (DLQI), and European Health Interview Survey (EHIS). Patients underwent standardized superficial skin surface biopsy of 4 areas of the face. D. folliculorum count greater than 5 mites/cm² was considered positive.

RESULTS

In relation to Demodex, there was an increase in skin sensitivity with higher Demodex density (p = 0.04). There was a statistically significant, weak positive correlation between skin sensitivity and DLQI score (r = 0.33, p = 0.00), and there was also a significant but very weak negative correlation between skin sensitivity and EUROHIS (r = -0.164, p = 0.002). Skin sensitivity was more common in patients with a concomitant dermatological disease (p = 0.01) and increased with more frequent cosmetic use (p = 0.00).

CONCLUSION

Alongside other risk factors, for the patients presenting with complaints of sensitive skin, investigating Demodex population density may help alleviate sensitive skin symptoms with appropriate therapies and preventive measures.

Which factors influence Demodex proliferation? A retrospective pilot study highlighting a possible role of subtle immune variations and sebaceous gland status

Demodex folliculorum and brevis are commensal mites that live in low densities in human pilosebaceous follicles as part of the normal adult microbiota, but that give rise to demodicosis and, possibly, rosacea, when they proliferate excessively. This proliferation is favored by various factors, including age, marked immunosuppression, sebaceous gland hyperplasia, and hypervascularization-related factors. To study possible factors influencing mite proliferation, we explored the effects of different variables on Demodex densities (Dd) in a retrospective study of two groups of subjects selected on the basis of their clinical diagnosis: Demodex+, consisting of subjects with demodicosis or with centro-facial papulopustules suggesting rosacea (n = 844, mean Dd 263.5 ± 8.9 D/cm² ), and Demodex-, consisting of subjects with other facial dermatoses or healthy facial skin (n = 200, mean Dd 2.3 ± 0.4 D/cm² ). Demodex densities were measured using two consecutive standardized skin surface biopsies (SSSB1 [superficial] and SSSB2 [deep]) taken from the same facial site on each subject. In the Demodex+ group: the SSSB1 decreased with age in women (p = 0.004), and the SSSB2 increased with age in men (p = 0.001) (the pattern was similar for SSSB1 + 2, but not statistically significant); Dds were lower in those who had received cortisone (either topically or systemically); 13 subjects (1.5%) had known immunosuppression, 62 (7.3%) had hypothyroidism, and in 20 (3.6% of the women) there was a reported link with pregnancy; 78 of the subjects (9.2%) were part of a pair from the same family or household; when associated bacterial infection was suspected, Staphylococcus epidermidis was often isolated. Our results suggest close interactions between the mite, sebaceous gland size and function, and subtle variations of immune status. Potential factors influencing Demodex proliferation should be further investigated, including hypothyroidism, pregnancy, corticosteroid administration, Staphylococcus epidermidis, contagiousity, and genetic background.

The effect of 577-nm pro-yellow laser on demodex density in patients with rosacea

BACKGROUND

The pro-yellow laser is a yellow light wavelength (577-nm) laser system. Rosacea is a chronic inflammatory disorder that occurs with facial flushing, erythema, papules, pustules, and telangiectasia. Demodex parasites (Demodex folliculorum and brevis) also play a role in the pathogenesis of rosacea.

AIM

The aim of our study is to evaluate the effect of pro-yellow laser on demodex density (Dd) in patients with rosacea.

PATIENTS/METHODS

This retrospective study was planned for the patients with rosacea whose demodex mite densities were examined and treated with pro-yellow laser and were evaluated between 2019 and 2020 in the cosmetology unit. The laser light was applied at a dose of 20 J/cm² in the scanner mode (the 80% coverage) in all the patients. The demodex density per cm² was routinely evaluated before the treatment, and the demodex density values in the fourth week after the treatment were recorded from the patients' files.

RESULTS

There were 27 females (79.4%) and seven males (20.6%) evaluated in the study. While the demodex density was 18.1 ± 10.7 (min: 0-max: 48, Q1:12-Q3:22) per cm² before the pro-yellow laser treatment in the cases, the demodex density was 10.2 ± 7.9 (min: 0-max: 30, Q1:4.75-Q3:12) per cm² in the fourth week after the treatment. After the pro-yellow laser treatment, the demodex intensity decreased significantly compared to before the laser treatment (p = 0.001). There was no significant correlation between the decrease in the density of the demodex mite and the success of the treatment (p = 0.46).

CONCLUSION

This is the first study in the literature investigating the change in demodex density in rosacea patients treated with pro-yellow laser therapy. In this study, it was shown that pro-yellow laser treatment is effective in reducing the density of demodex.