New insights into rosacea pathophysiology: a review of recent findings

Rosacea is strongly associated with melanoma in Caucasians

Rosacea is often considered a cosmetic problem but is known to be associated with a variety of comorbidities. To identify such risks, we generated two age- and sex-matched real-world cohorts of 122,444 patients each with and without rosacea. In contrast to earlier studies, we found significant associations with malignant melanoma (OR 6.02, 95% CI 5.76-6.32). This association does not exist for an Asian sub-cohort, which could explain previous inconclusive or conflicting reports. Several strongly associated comorbidities like visual disturbances (ICD-10: H53-H54; OR 4.80, 4.68-4.92), metabolic disorders (E73-E79; OR 3.17, 3.11-3.22), joint problems (M25; OR 4.16, 4.08-4.25) and type 2 diabetes (E11; OR 1.62, 1.58-1.65) should be watched as a risk for rosacea patients. Rosacea is associated with some comorbidities and ethnicity may be a risk factor in melanoma development. The retrospective nature of this study and the sole use of ICD-10 code based filtering calls for future validation of our findings. Additionally, confounding factors such as skin type and previous UV exposure should be included in future studies.

Erenumab for Treatment of Persistent Erythema and Flushing in Rosacea: A Nonrandomized Controlled Trial

Importance

Treatment of erythema and flushing in rosacea is challenging. Calcitonin gene-related peptide (CGRP) has been associated with the pathogenesis of rosacea, raising the possibility that inhibition of the CGRP pathway might improve certain features of the disease.

Objective

To examine the effectiveness, tolerability, and safety of erenumab, an anti-CGRP-receptor monoclonal antibody, for the treatment of rosacea-associated erythema and flushing.

Design, Setting, and Participants

This single-center, open-label, single-group, nonrandomized controlled trial was conducted between June 9, 2020, and May 11, 2021. Eligible participants included adults with rosacea with at least 15 days of either moderate to severe erythema and/or moderate to extreme flushing. No concomitant rosacea treatment was allowed throughout the study period. Visits took place at the Danish Headache Center, Copenhagen University Hospital, Rigshospitalet in Copenhagen, Denmark. Participants received 140 mg of erenumab subcutaneously every 4 weeks for 12 weeks. A safety follow-up visit was performed at week 20. Data analysis occurred from January 2023 to January 2024.

Intervention

140 mg of erenumab every 4 weeks for 12 weeks.

Main Outcomes and Measures

The primary outcome was mean change in the number of days with moderate to extreme flushing during weeks 9 through 12, compared with the 4-week run-in period (baseline). The mean change in number of days with moderate to severe erythema was a secondary outcome. Adverse events were recorded for participants who received at least 1 dose of erenumab. Differences in means were calculated with a paired t test.

Results

A total of 30 participants (mean [SD] age, 38.8 [13.1] years; 23 female [77%]; 7 male [23%]) were included, of whom 27 completed the 12-week study. The mean (SD) number of days with moderate to extreme flushing was reduced by -6.9 days (95% CI, -10.4 to -3.4 days; P < .001) from 23.6 (5.8) days at baseline. The mean (SD) number of days with moderate to severe erythema was reduced by -8.1 days (95% CI, -12.5 to -3.7 days; P < .001) from 15.2 (9.1) days at baseline. Adverse events included transient mild to moderate constipation (10 participants [33%]), transient worsening of flushing (4 participants [13%]), bloating (3 participants [10%]), and upper respiratory tract infections (3 participants [10%]), consistent with previous data. One participant discontinued the study due to a serious adverse event (hospital admission due to gallstones deemed unrelated to the study), and 2 participants withdrew consent due to lack of time.

Conclusions and Relevance

These findings suggest that erenumab might be effective in reducing rosacea-associated flushing and chronic erythema (participants generally tolerated the treatment well, which was consistent with previous data), and that CGRP-receptor inhibition holds potential in the treatment of erythema and flushing associated with rosacea. Larger randomized clinical trials are needed to confirm this finding.

Trial Registration

ClinicalTrials.gov Identifier: NCT04419259.

Elevated plasma levels of calcitonin gene-related peptide in individuals with rosacea: A cross-sectional case-control study

BACKGROUND

Understanding the role of calcitonin gene-related peptide (CGRP) in the pathogenesis of rosacea might provide new therapeutic avenues for individuals with this disease.

OBJECTIVE

To compare plasma levels of CGRP between individuals with rosacea and healthy controls.

METHODS

In this cross-sectional case-control study conducted in Copenhagen, Denmark, we collected blood samples from the antecubital vein from adults with rosacea and from healthy controls.

RESULTS

We enrolled 123 individuals with rosacea and 68 healthy controls. After adjusting for age and sex, plasma levels of CGRP were significantly higher in individuals with rosacea (mean, 95% confidence interval: 140.21 pmol/L, 128.50-151.92 pmol/L), compared with controls (110.77 pmol/L, 99.91-120.14 pmol/L, p = 0.002). Plasma levels of CGRP were not affected by age, sex, BMI, concomitant migraine, rosacea sub- or phenotype, concomitant disease or current treatment.

LIMITATIONS

Participants were not age-, sex- and BMI-matched.

CONCLUSIONS AND RELEVANCE

Elevated plasma levels of CGRP in individuals with rosacea suggest a role of CGRP in the pathogenesis of rosacea. Targeting CGRP signalling might hold therapeutic promise in people affected by this disease.

CLINICALTRIALS

GOV LISTING

NCT03872050.

Colchicine Alleviates Rosacea by Inhibiting Neutrophil Inflammation Activated by the TLR2 Pathway

Rosacea is a chronic facial inflammatory skin disease that occurs with dysfunction of the immune system. Colchicine was reported to have anti-inflammatory properties. However, the impact of colchicine on rosacea remains unclear. In the present study, the phenotype of rosacea lesions was evaluated by the redness score, inflammatory biomarkers were analyzed by reverse transcription PCR (RT‒PCR), and the infiltration of inflammatory cells was assessed by IHC analysis and immunofluorescence in a rosacea-like mouse model. In vitro, RT‒PCR was used to identify the inflammatory factors that Toll-like receptor 2 (TLR2) agonist caused neutrophils to produce, and immunofluorescence and coimmunoprecipitation were used to identify putative signalling pathways. We found that skin erythema and histopathological alterations, as well as elevated proinflammatory factors (IL-1β, IL-6, TNFα, CXCL2) and CAMP, were significantly ameliorated by colchicine treatment in LL37-induced rosacea-like mice. In addition, colchicine reduced the colocalization of TLR2 and neutrophils and the formation of neutrophil extracellular trap networks (NET) in mouse lesions. In neutrophils, colchicine markedly reduced TLR2 agonist-induced inflammatory biomarker expression, NET formation, and ROS production. Moreover, we found that LL37 could bind to TLR2 upon activation of TLR2 in neutrophils. Importantly, colchicine could repress the combination of TLR2 and LL37 in vivo. Finally, bioinformatics methods further validated the key molecules of neutrophil-related inflammation in rosacea, which is consistent with our experimental findings. Collectively, colchicine ameliorated rosacea-like dermatitis by regulating the neutrophil immune response activated by the TLR2 pathway, indicating that it could be an effective therapeutic option for patients with rosacea.

OPN promotes pro-inflammatory cytokine expression via ERK/JNK pathway and M1 macrophage polarization in Rosacea

Rosacea is a chronic inflammatory dermatosis that involves dysregulation of innate and adaptive immune systems. Osteopontin (OPN) is a phosphorylated glycoprotein produced by a broad range of immune cells such as macrophages, keratinocytes, and T cells. However, the role of OPN in rosacea remains to be elucidated. In this study, it was found that OPN expression was significantly upregulated in rosacea patients and LL37-induced rosacea-like skin inflammation. Transcriptome sequencing results indicated that OPN regulated pro-inflammatory cytokines and promoted macrophage polarization towards M1 phenotype in rosacea-like skin inflammation. In vitro, it was demonstrated that intracellular OPN (iOPN) promoted LL37-induced IL1B production through ERK1/2 and JNK pathways in keratinocytes. Moreover, secreted OPN (sOPN) played an important role in keratinocyte-macrophage crosstalk. In conclusion, sOPN and iOPN were identified as key regulators of the innate immune system and played different roles in the pathogenesis of rosacea.

Integrated Omics Reveal the Molecular Characterization and Pathogenic Mechanism of Rosacea

Recent efforts have described the transcriptomic landscape of rosacea. However, little is known about its proteomic characteristics. In this study, the proteome and phosphoproteome of lesional skin, paired nonlesional skin, and healthy skin were analyzed by liquid chromatography coupled with tandem mass spectrometry. The molecular characteristics and potential pathogenic mechanism of rosacea were demonstrated by integrating the proteome, phosphoproteome, and previous transcriptome. The proteomic data revealed a significant upregulation of inflammation- and axon extension-related proteins in lesional skin and nonlesional skin versus in healthy skin, implying an inflammatory and nerve-hypersensitive microenvironment in rosacea skin. Of these, axon-related proteins (DPYSL2 and DBNL) were correlated with the Clinician's Erythema Assessment score, and neutrophil-related proteins (ELANE and S100A family) were correlated with the Investigator's Global Assessment score. Moreover, comorbidity-related proteins were differentially expressed in rosacea; of these, SNCA was positively correlated with Clinician's Erythema Assessment score, implying a potential correlation between rosacea and comorbidities. Subsequently, the integrated proteome and transcriptome demonstrated consistent immune disturbances at both the transcriptional and protein levels. The integrative analysis of the proteome and phosphoproteome revealed the key transcription factor network and kinase network that drive the dysregulation of immunity and vasculature in rosacea. In conclusion, our multiomics analysis enables more comprehensive insight into rosacea and offers an opportunity for, to our knowledge, previously unreported treatment strategies.

Dendrobium polysaccharide (DOP) ameliorates the LL-37-induced rosacea by inhibiting NF-κB activation in a mouse model

BACKGROUND

Rosacea, a common chronic inflammatory skin disease worldwide, is currently incurable with complex pathogenesis. Dendrobium polysaccharide (DOP) may exert therapeutic effects on rosacea via acting on the NF-κB-related inflammatory and oxidative processes.

MATERIALS AND METHODS

In this study, an LL-37-induced rosacea-like mouse model was established. HE staining was used to assess the skin lesions, erythema severity scores, pathological symptoms, and inflammatory cell numbers of mice in each group. The inflammation level was quantitatively analyzed using enzyme-linked immunosorbent assay (ELISA) and reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR). The expression levels of TLR4 and p-NF-κB were finally detected.

RESULTS

DOP improved skin pathological symptoms of rosacea mice. DOP also alleviated the inflammation of rosacea mice. Moreover, the TLR4/NF-κB pathway was observed to be inhibited in the skin of mice after DOP application. These findings evidenced the anti-inflammatory effects of DOP on the LL-37-induced rosacea mouse model. DOP could inhibit NF-κB activation, suppress neutrophil infiltration, and reduce pro-inflammatory cytokines production, which may be the reason for DOP protecting against rosacea.

CONCLUSION

This study may propose an active candidate with great potential for rosacea drug development and lay a solid experimental foundation for promoting DOP application in rosacea therapy.

Advances in Relationship Between Alcohol Consumption and Skin Diseases

Throughout history, alcohol consumption has been an integral part of human culture. Alcohol consumption, alcoholism in particular, influences the onset and progression of liver diseases, neurological disorders, and multiple types of cancer. However, the role of alcohol consumption in influencing skin diseases has often been overlooked. In this review, we present the progress of research investigating the effects and potential mechanisms of action of alcohol consumption on acne, rosacea, psoriasis, atopic dermatitis, melanoma, and non-melanoma skin cancer.

Evaluation of Dermatological and Neurological Aspects of the Relationship between Rosacea and Headaches

This study aimed to investigate the relationship between rosacea and headaches, focusing on different subtypes, as well as the associated clinical features and triggering factors. In this prospective study, 300 patients diagnosed with rosacea and 320 control subjects without rosacea or any connected mast cell activation illness were included. Patients with rosacea were assessed by a dermatologist according to the 2019 updated rosacea classification (ROSCO panel). Accordingly, patients were classified based on their predominant rosacea subtype as follows: erythematotelangiectatic (ETR), papulopustular (PPR), or phymatous (RhR). Patients experiencing headaches were assessed using the International Headache Classification. Headaches were categorized as migraine, tension-type headaches (TTHs), secondary types (STHs), and cluster-type headaches (CTHs). The ratio of headache was 30.3% in the rosacea group, which did not show a significant difference compared to the control group (30.3% vs. 25.0%, p = 0.138). In 81.3% of rosacea patients with headaches, headache onset occurred after the diagnosis of rosacea. The rate of patients with headaches was higher in the ETR group compared to the PPR and RhR groups (35.2% vs. 16.2% vs. 23.1%, p = 0.007, respectively). In terms of headache subtypes, the rates of patients with migraine and STHs were higher in the ETR group compared to the PPR and RhR groups, while the rate of patients with TTHs was higher in the RhR group. A positive correlation was found between rosacea severity and migraine severity (r = 0.284, p < 0.05). Among the triggering factors for rosacea, only sunlight was found to be associated with headaches. Lower age, female gender, and moderate to severe rosacea severity were identified as independent factors increasing the likelihood of headaches. A significant portion of rosacea patients experience headaches. Particularly, different subtypes of rosacea may be associated with various types of headaches. This study, highlighting the connection between migraine and ETR, is a pioneering work that demonstrates common pathogenic mechanisms and potential triggers.

Association Between Acid-Suppressive Drugs and Risk of Rosacea: Retrospective Study Using the Korean National Health Insurance Service-National Sample Cohort

BACKGROUND

Rosacea is a common inflammatory skin disease with multiple etiologies. Proton pump inhibitors (PPIs) and histamine-2 receptor antagonists (H2RA) are acid suppressive drugs widely used for gastrointestinal (GI) diseases, and long-term use has been reported to be associated with dysbiosis which is a potential risk for development of rosacea. This study aimed to study the association between rosacea and acid suppressants in the Korean national cohort.

METHODS

We used Korean National Health Insurance Service-National Sample Cohort data of 749,166 patients with upper GI diseases between 2001 and 2013. Duration of acid suppressants was compared between patients with and without rosacea together with other sociodemographic characteristics and hazard ratios were estimated.

RESULTS

Longer use of acid suppressants was significantly associated with increased risk of rosacea. After adjustment for possible confounders, increased cumulative defined daily dose was significantly associated with risk of rosacea (odds ratio [OR], 1.55; 95% confidence interval [CI], 1.20-2.00; P = 0.001). Other factors significantly associated with risk of rosacea include residing in the rural area (OR, 2.58; 95% CI, 2.18-3.06; P < 0.001), greater Charlson Comorbidity Index score (OR, 1.45; 95% CI, 1.15-1.83; P = 0.002), and comorbidities (malignancy, thyroid disease, and depression).

CONCLUSION

Results from our study indicate that H2RA or PPI is associated with the occurrence of rosacea among patients with GI diseases in the Korean population. The risk was increased in dose-dependent manner, even after adjusting for confounding variables. Clinicians should be aware of risks associated with prolonged use of acid suppressive drugs.

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.

Rosacea and Its Association With Malignancy: Systematic Review

BACKGROUND

Rosacea is a chronic inflammatory skin condition that predominantly manifests as facial flushing, irritation, and acne. Rosacea and cancer are thought to be linked by the commonality of inflammatory and immune response dysfunction. Studies that have looked into this possible association have reported mixed results.

OBJECTIVE

Given the conflicting literature on this topic, our study sought to evaluate the overall association between rosacea and several cancers commonly investigated in the literature.

METHODS

A systematic review was conducted using the Cochrane, PubMed, Embase, and Ovid databases. Studies were screened independently for inclusion of rosacea and glioma and breast, thyroid, hepatic, or skin cancers. Using information from the articles, rosacea and each cancer were categorized as having a positive, negative, or unclear association.

RESULTS

Our systematic review included 39 full-text studies that investigated the association between rosacea and various malignancies. Among the malignancies of concern, 41% (16/39) of the studies reported an association with basal cell carcinoma, with 2 cohorts revealing an adjusted risk ratio (RR) of 1.50 (95% CI 1.35-1.67) and 0.72 (95% CI 0.56-0.93). In total, 33% (13/39) of the studies reported an association with squamous cell carcinoma, with 2 cohorts revealing an adjusted RR of 1.4 (95% CI 1.02-1.93) and 1.30 (95% CI 0.90-1.88). A total of 8% (3/39) of the studies reported an association between breast cancer and melanoma, with breast cancer cohorts revealing an adjusted RR of 8.453 (95% CI 1.638-43.606), 1.03 (95% CI 0.89-1.20), and 1.36 (95% CI 1.18-1.58) and melanoma cohorts revealing an adjusted RR of 1.10 (95% CI 0.95-1.27), 0.63 (95% CI 0.47-0.85), and 0.96 (95% CI 0.57-1.62). A total of 5% (2/39) of the studies reported an association among nonmelanoma skin cancers, hepatic cancer, and thyroid carcinomas, with nonmelanoma skin cancer cohorts revealing an adjusted RR of 1.36 (95% CI 1.26-1.47) and 2.66 (95% CI 1.53-4.61), hepatic cancer cohorts revealing an adjusted RR of 1.42 (95% CI 1.06-1.90) and 1.32 (95% CI 0.89-1.95), and thyroid carcinoma cohorts revealing an adjusted RR of 1.06 (95% CI 0.68-1.65) and 1.59 (95% CI 1.07-2.36). Only 1 cohort reported an association with glioma, revealing an adjusted RR of 1.36 (95% CI 1.18-1.58). According to our review, patients with rosacea were statistically more likely to have nonmelanoma skin cancers, breast cancer, and glioma. Rosacea was not found to be substantially associated with melanoma. The associations between rosacea and hepatic and thyroid cancers were unclear because of conflicting results.

CONCLUSIONS

The current literature shows that rosacea is significantly associated with increased odds of nonmelanoma skin cancers, glioma, and breast cancer. Rosacea does not appear to be associated with melanoma. Further studies should be conducted to clarify the association between thyroid and hepatic cancers and rosacea.

TLR7 promotes skin inflammation via activating NFκB-mTORC1 axis in rosacea

Rosacea is a chronic inflammatory skin disease originated from damaged skin barrier and innate/adaptive immune dysregulation. Toll-like receptors (TLRs) sense injured skin and initiate downstream inflammatory and immune responses, whose role in rosacea is not fully understood. Here, via RNA-sequencing analysis, we found that the TLR signaling pathway is the top-ranked signaling pathway enriched in rosacea skin lesions, in which TLR7 is highlighted and positively correlated with the inflammation severity of disease. In LL37-induced rosacea-like mouse models, silencing TLR7 prevented the development of rosacea-like skin inflammation. Specifically, we demonstrated that overexpressing TLR7 in keratinocytes stimulates rapamycin-sensitive mTOR complex 1 (mTORC1) pathway via NFκB signaling. Ultimately, TLR7/NFκ B/mTORC1 axis promotes the production of cytokines and chemokines, leading to the migration of CD4+T cells, which are infiltrated in the lesional skin of rosacea. Our report reveals the crucial role of TLR7 in rosacea pathogenesis and indicatesa promising candidate for rosacea treatments.

Rosacea Topical Treatment and Care: From Traditional to New Drug Delivery Systems

Rosacea is a multifactorial chronic inflammatory dermatosis characterized by flushing, nontransient erythema, papules and pustules, telangiectasia, and phymatous alterations accompanied by itching, burning, or stinging, the pathophysiology of which is not yet fully understood. Conventional topical treatments usually show limited efficacy due to the physical barrier property of the skin that hinders skin penetration of the active ingredients, thereby hampering proper drug skin delivery and the respective therapeutic or cosmetic effects. New advances regarding the physiopathological understanding of the disease and the underlying mechanisms suggest the potential of new active ingredients as promising therapeutic and cosmetic approaches to this dermatosis. Additionally, the development of new drug delivery systems for skin delivery, particularly the potential of nanoparticles for the topical treatment and care of rosacea, has been described. Emphasis has been placed on their reduced nanometric size, which contributes to a significant improvement in the attainment of targeted skin drug delivery. In addition to the exposition of the known pathophysiology, epidemiology, diagnosis, and preventive measures, this Review covers the topical approaches used in the control of rosacea, including skin care, cosmetics, and topical therapies, as well as the future perspectives on these strategies.

Conjunctival Microbiota and Blepharitis Symptom Scores in Patients With Ocular Rosacea

PURPOSE

Investigation of the relationship between blepharitis-related symptom scores, tear film functions, and conjunctival microbiota in patients with ocular rosacea (OR) compared with healthy controls was aimed.

METHODS

Consecutive 33 eyes of 33 patients with OR who were admitted from the dermatology clinic and age-matched and gender-matched 30 healthy controls were included in the study. Tear breakup time (TBUT), Schirmer score, and blepharitis symptom score (BLISS) were recorded for each patient. For the bacteriological examination, bacterial culture was obtained by inoculating the samples on chocolate agar, blood agar, and fluid thioglycollate medium. The growth of different colonies of bacteria was identified using matrix-assisted laser desorption or ionization time-of-flight mass spectrometry.

RESULTS

Bacterial culture positivity was observed in 13 eyes (39.4%) in the patients with OR and 10 eyes (33.3%) in the controls ( P =0.618). Patients with OR showed worse TBUT and Schirmer scores, and higher BLISSs ( P =0.005, P =0.007, and P =0.001, respectively). Patients with OR with conjunctival culture-positive results showed higher BLISSs (8.0±4.7) compared with those with negative results (4.7±2.3; P <0.001). The most frequent bacteria was Micrococcus luteus (18.2%) in patients with OR and Staphylococcus epidermidis (20.0%) in the controls.

CONCLUSION

This pilot study showed that patients with OR had similar conjunctival culture positivity compared with healthy controls. However, the observation of different dominant bacterial species in conjunctival microbiota and the observation of worse BLISSs in patients with OR with positive culture might suggest a potential role of conjunctival microbiota in the pathogenesis of OR.

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.

Whole genome sequencing identifies genetic variants associated with neurogenic inflammation in rosacea

Rosacea is a chronic inflammatory skin disorder with high incidence rate. Although genetic predisposition to rosacea is suggested by existing evidence, the genetic basis remains largely unknown. Here we present the integrated results of whole genome sequencing (WGS) in 3 large rosacea families and whole exome sequencing (WES) in 49 additional validation families. We identify single rare deleterious variants of LRRC4, SH3PXD2A and SLC26A8 in large families, respectively. The relevance of SH3PXD2A, SLC26A8 and LRR family genes in rosacea predisposition is underscored by presence of additional variants in independent families. Gene ontology analysis suggests that these genes encode proteins taking part in neural synaptic processes and cell adhesion. In vitro functional analysis shows that mutations in LRRC4, SH3PXD2A and SLC26A8 induce the production of vasoactive neuropeptides in human neural cells. In a mouse model recapitulating a recurrent Lrrc4 mutation from human patients, we find rosacea-like skin inflammation, underpinned by excessive vasoactive intestinal peptide (VIP) release by peripheral neurons. These findings strongly support familial inheritance and neurogenic inflammation in rosacea development and provide mechanistic insight into the etiopathogenesis of the condition.

The Relationship Between Rosacea and Inflammatory Bowel Disease: A Systematic Review and Meta-analysis

INTRODUCTION

Rosacea and inflammatory bowel disease (IBD) are chronic inflammatory disorders of the skin and the gut, which are interfaces between the environment and the human body. Although growing evidence has implicated a possible link between rosacea and IBD, it remains unclear whether IBD increases the risk of rosacea and vice versa. Therefore, we investigated the association between rosacea and IBD in this study.

METHODS

We performed a systematic review and meta-analysis according to the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) guidelines.

RESULTS

Eight eligible studies were included in this meta-analysis. Overall, the prevalence of rosacea was higher in the IBD group than in the control group, with a pooled odds ratio (OR) of 1.86 (95% confidence interval [CI](1), 1.52-2.26). Both the Crohn's disease and the ulcerative colitis groups had higher prevalences of rosacea than the control group, with ORs of 1.74 (95% CI 1.34-2.28) and 2.00 (95% CI 1.63-2.45), respectively. Compared with those in the control group, the risks of IBD, Crohn's disease, and ulcerative colitis were significantly higher in the rosacea group, with incidence rate ratios of 1.37 (95% CI 1.22-1.53), 1.60 (95% CI 1.33-1.92), and 1.26 (95% CI 1.09-1.45), respectively.

CONCLUSION

Our meta-analysis suggests that IBD is bidirectionally associated with rosacea. Future interdisciplinary studies are needed to better understand the mechanism of interaction between rosacea and IBD .

GBP5 exacerbates rosacea-like skin inflammation by skewing macrophage polarization towards M1 phenotype through the NF-κB signalling pathway

BACKGROUND

Rosacea is a chronic inflammatory skin disease with increased macrophage infiltration. However, the molecular mechanism remains unclear.

OBJECTIVES

To determine the significance of macrophage infiltration, and the correlation between Guanylate-binding protein 5 (GBP5) and polarization of macrophages in rosacea-like inflammation.

METHODS

Here we tested the hypothesis that Guanylate-binding protein 5 (GBP5) aggravates rosacea-like skin inflammation by promoting the polarization of the M1 macrophages through the NF-κB signalling pathway. We depleted macrophage by injecting clodronate-containing liposomes. We next explored the association between GBP5 and macrophage in rosacea tissue through transcriptome analysis and immunofluorescence analysis. We evaluated the severity of rosacea-like skin inflammation when BALB/c mice were injected with GBP5 siRNA intradermally daily for three consecutive days. At last, to study the causality of knocking down GBP5-blunted M1 macrophage polarization, THP-1 cell was treated with GBP5 siRNA.

RESULTS

Macrophage depletion ameliorated rosacea-like skin inflammation in mice, implying the important role of macrophages in rosacea. Based on the transcriptome analysis, Guanylate-binding protein 5 (GBP5) was identified as hub gene that was associated with macrophage infiltration in rosacea. Next, we found that GBP5 expression was significantly upregulated in rosacea tissues and positively correlated with macrophage infiltration, the immunofluorescence analysis revealed the co-localization between GBP5 and macrophages. In vivo, silencing of GBP5 attenuated rosacea-like skin inflammation in the LL-37-induced mouse model and suppressed the expression of M1 signature genes such as IL-6, iNOS and TNF-a. In vitro, knocking down GBP5 significantly blunted the polarization of the M1 macrophages partly by repressing the activation of the NF-κB signalling pathways.

CONCLUSIONS

Together, our study revealed the important role of macrophages in rosacea and identified GBP5 as a key regulator of rosacea by inducing M1 macrophage polarization via NF-κB signalling pathways.

Differences in clinical characteristics of rosacea across age groups: A retrospective study of 840 female patients

BACKGROUND

Aging remains a common influencing factor for many diseases. Previous studies have shown that age is significantly associated with rosacea among female cases and that the incidence of rosacea increases with age. However, previous studies did not specifically analyze the clinical characteristics of different age groups.

OBJECTIVE

This study aimed to analyze and compare the clinical characteristics of female patients of rosacea among different age groups.

METHODS

We conducted a retrospective study of 840 female rosacea subjects and compared cutaneous features, aggravating factors, systemic diseases, and psychological states across age groups. The patients were divided into three groups according to their age at diagnosis: ≤30 years，31-44 years，and ≥45 years.

RESULTS

In our study, the mean age of subjects was 35.9 ± 10.23 years. The common symptoms included telangiectasia (82.6%), persistent erythema (82.0%), burning/stinging sensation (89.3%), dry sensation (74.0%), and pruritis (41.9%). Hot temperature (89.9%), emotional changes (67.3%), spicy food (55.6%), and sun exposure (50.7%) were the common aggravating factors. Some patients had comorbidities of systemic disorders (20.4%). Of the patients, 48.8% presented with anxiety and 35.2% with depression. The clinical characteristics were found to be significantly different among the different age groups. Middle-aged and older patients (≥45 years) were more likely to have more serious persistent erythema and telangiectasia. And these patients were relatively less affected by some of the influencing factors and had more systemic diseases of the digestive system, endocrine metabolic system, and cardiovascular system (p < 0.05).

CONCLUSION

We revealed the impact of age on the characteristics of rosacea, which indicated that the clinical features of rosacea are more complex and more difficult to treat in females over the age of 45.

Paroxetine is an effective treatment for refractory erythema of rosacea: Primary results from the Prospective Rosacea Refractory Erythema Randomized Clinical Trial

BACKGROUND

Patients with refractory erythema of rosacea have limited treatment options.

OBJECTIVE

To evaluate the efficacy and safety of a 12-week course of paroxetine for moderate-to-severe erythema of rosacea.

METHODS

In a multicenter, randomized, double-blinded, placebo-controlled trial, patients with refractory erythema of rosacea were randomly assigned (1:1) to receive paroxetine 25 mg daily or placebo for 12 weeks.

RESULTS

Overall, 97 patients completed the study (paroxetine: 49; placebo: 48). The primary end point was the proportion of participants achieving Clinical Erythema Assessment success (defined as Clinical Erythema Assessment score of 0, 1, or ≥2-grade improvement from baseline) at week 12; this was significantly greater in the paroxetine group than in the placebo group (42.9% vs 20.8%, P = .02). Some secondary end points were met, such as flushing success with point reductions ≥2 (44.9% vs 25.0%, P = .04) and improvement in overall flushing (2.49 ± 3.03 vs 1.68 ± 2.27, P = .047), burning sensation (46.9% vs 18.8%, P = .003), and depression (P = .041). The most reported adverse events associated with paroxetine were dizziness, lethargy, nausea, dyspepsia, and muscle tremors.

LIMITATIONS

Only a single-dosage regimen of paroxetine within a 12-week study was evaluated.

CONCLUSIONS

Paroxetine is an effective and well-tolerated alternative treatment for moderate-to-severe erythema of rosacea.

Associations of polysocial risk score with incident rosacea: a prospective cohort study of government employees in China

Background

The associations between single risk factors and incident rosacea have been reported, but the effects of social risk factors from multiple domains coupled remain less studied.

Objectives

To quantify the influence of social determinants on rosacea comprehensively and investigate associations between the polysocial risk score (PsRS) with the risks of incident rosacea.

Methods

This was a prospective cohort study of government employees undertaken from January 2018 to December 2021 among participants aged >20 from five cities in Hunan province of China. At baseline, information was collected by a questionnaire and participants were involved in an examination of the skin. Dermatologists with certification confirmed the diagnosis of rosacea. The skin health status of participants was reassessed every year since the enrolment of study during the follow-up period. The PsRS was determined using the nine social determinants of health from three social risk domains (namely socioeconomic status, psychosocial factors, and living environment). Incident rosacea was estimated using binary logistic regression models adjusted for possible confounding variables.

Results

Among the 3,773 participants who completed at least two consecutive skin examinations, there were 2,993 participants included in the primary analyses. With 7,457 person-years of total follow-up, we detected 69 incident rosacea cases. After adjustment for major confounders, participants in the group with high social risk had significantly raised risks of incident rosacea with the adjusted odds ratio (aOR) being 2.42 (95% CI 1.06, 5.55), compared to those in low social risk group.

Conclusion

Our findings suggest that a higher PsRS was associated with an elevated risk of incident rosacea in our study population.

Fractional treatment of rosacea by LBO 532 nm laser with “one shot” procedure: A preliminary study

Rosacea is a chronic skin disease prevalently affecting the center of the face. The permanent erythema of skin face represents its typical sign. Further common features are face flushing, telangiectasias, and inflammatory presence of oedema, papules and pustules. The aim of this study was to investigate the use of LBO 532nm laser in the treatment of this disease. Ten subjects of both sex and middle age affected by rosacea in erithemato/teleangectatic stage were treated by a LBO 532nm laser single session. Discomfort evaluation during and after the treatment, one session results as well as incidence of the side effects were evaluated, with 6 months follow up. Positive results were obtained after only one session in total safety with minimal patients discomfort and without undesired effects during treatment. The study confirmed International literature data suggesting the use of laser and light devices as elective treatment of this disease. IPL, dye lasers and 532nm laser are the devices more used and the last seems to represent the gold standard for 1,2,3 phototypes. This clinical trial, with the limitations due to the small number of patients, indicated that “one session LBO 532nm laser treatment” represents an interesting and innovative approach in the therapy of the erythemato/telangectatic rosacea.

Combined therapy of 5-aminolevulinic acid photodynamic therapy and intense pulsed light for rosacea

Rosacea is difficult to treat. Therefore, new alternative modalities are necessary to demonstrate. The present study was conducted to assess the efficacy and safety of the combined therapy of 5-aminolevulinic acid photodynamic therapy (ALA-PDT) and intense pulsed light (IPL) for rosacea to provide a new treatment option for rosacea. The study was conducted from November 2017 to April 2019 at the Department of Dermatology, The First Hospital of China Medical University. Patients aged 18-65 years and diagnosed clinically as erythematotelangiectatic (ET) or papulopustular (PP) rosacea were enrolled. Three times of ALA-PDT at 10 days interval followed by 3 times of IPL at 3-4 weeks interval were defined as 1 session and applied to the whole face of each patient. ALA-PDT: 5% ALA, red light (fluency dose 60-100 mW/cm2, 20 min); IPL: 560/590/640 nm, double/triple-pulse mode, pulse width 3.0 to 4.5 ms, delay time 30-40 ms, energy fluency 14-17 J/cm2. Ten patients were enrolled in the study. Among them, 4 patients received only 1 session, while 6 patients received 2 sessions. After all treatments, 50% of patients achieved 75-100% improvement, and 30% achieved 50-75% improvement. Forty percent of patients were graded very satisfaction and 30% graded moderate satisfaction. All noninvasive measurements showed no significant differences among all time points (p > 0.05). The side effects were pain, burning sensation, itching, erythema, desquamation, slight edema, slight exudation, and hyperpigmentation. All of which were tolerable and recovered in a few days. The combined therapy of ALA-PDT and IPL showed an effective option for rosacea with a safety profile.

A Cross-Sectional Study on the Relationship Between Rosacea Severity and Quality of Life or Psychological State

Background

Rosacea appears predominantly in highly visible areas of the facial region.

Objective

To investigate the psychological status and quality of life(QOL) of rosacea.

Methods

We used a hospital-based cross-sectional analytical study design between Jan 1, 2020, and Jan 1, 2021. We analyzed the differences and correlations in the severity of rosacea and its impacts on QOL and mental health, separately.

Results

469 patients with rosacea were included. The mean Dermatology Life Quality Index (DLQI) score was 12.6±7.7 and the affected level of DLQI was moderately severe. The total score of Rosacea-specific Quality-of-Life instrument (RosQol) was 2.34 ± 0.84, and the scores of emotion, symptoms, and function were 2.41 ± 0.99, 2.37 ±0.82, and 2.03 ± 0.89, respectively. 44.8% of patients suffered from anxiety and 37.5% from depression. There were statistically significant differences in the incidence of anxiety (p <0.001), the DLQL (p =0.02), RosQol emotion (p =0.04), symptom (p <0.01) and function (p =0.02) scores in the different severity. In addition, worsening QOL was significantly associated with increased disease severity [Spearman's rank correlation index (r) ranging from 0.171 to 0.266,p<0.01 (RosQol); r =0.104,p =0.024 (DLQI)]. There was also a positive correlation between anxiety [r =0.155; p<0.01] and the different severity levels.

Conclusion

Rosacea maybe has a greater significant impact on patient's QOL and mental health. And the impact of QOL and mental health tend to deteriorate significantly with increasing disease severity. The relationship suggests that QOL assessment is of great interest in clinical practice and should be further explored.

Treatment strategies, including antibiotics, to target the immune component of rosacea

INTRODUCTION

Recent advances in the understanding of the pathophysiology of rosacea have led to increased focus on the disease's immunologic etiology and to the development of immunologically based treatments. With many patients suffering from incomplete control, addressing the immune components of the disease process may provide a more effective treatment option for rosacea patients that may improve quality of life.

AREAS COVERED

This review will provide a brief overview of the pathophysiology of rosacea, as well as specific immunologic contributions to the disease state. Current standard-of-care treatments will be described, including anti-parasitic, anti-inflammatory agents, and antibiotics. Emphasis will be placed on treatments that target the immune components of the disease process.

EXPERT OPINION

Rosacea remains a difficult dermatologic disease to treat, partially due to an incomplete understanding of the disease pathophysiology. The immune pathophysiology of rosacea, particularly the key role of inflammation, has been clarified over the past decade. Identification of specific molecules, including cytokines and nuclear transcription factors, may allow for the development of targeted rosacea-specific biologic and topical treatments. However, medication nonadherence is a limiting factor to achieving symptomatic control among rosacea patients. Focusing on the development of oral or injectable forms of therapy may circumvent poor adherence.

Mediation roles of neutrophils and high-density lipoprotein (HDL) on the relationship between HLA-DQB1 and rosacea

BACKGROUND

Though the previous genome-wide association studies found the association between HLA alleles and rosacea in the European populations, the data is lacking among the Asians. Moreover, neutrophils are important in the immune-related mechanism of rosacea, and dyslipidemia is closely related to rosacea. We aimed to explore the association between HLA genes and rosacea in Chinese rosacea patients, as well as the mediation effect of neutrophils, high-density lipoprotein (HDL) and low-density lipoprotein (LDL) on the relationship between HLA genes and rosacea.

METHODS

A total of 249 rosacea and 150 controls were ranked by the international investigator global rosacea severity scores. HLA genes, neutrophils, HDL, and LDL were detected. And their mediation effects on the relationship between HLA and rosacea risk or severity were analysed.

RESULTS

HLA-DQB1*03:03 allele (OR = 41.89, 95% CI: 9.80 ∼ 179.09, p = 4.7*10^-7), HLA-DQB1*04:02 allele (OR = 0.16, 95% CI: 0.03 ∼ 0.81, p = 0.026) and HLA-DQB1*03:03/05:02 genotype (OR = 5.57, 95% CI: 1.13 ∼ 27.52, p = 0.0351) were significantly associated with rosacea. Moreover, HLA-DQB1*03:03 allele (b = 1.434, SE = 0.217, p = 2.0*10^-10), HLA-DQB1*05:01 allele (b = 0.894, SE = 0.33520, p = 0.008) and HLA-DQB1*03:03/06:01 genotype (b = 0.998, SE = 0.472, p = 0.040) were positively associated with rosacea severity. Furthermore, we found both neutrophils and HDL, instead of LDL, have mediation effects on the relationship between HLA-DQB1*03:03 and risk or severity of rosacea.

CONCLUSIONS

We discovered novel susceptible HLA alleles for rosacea in the Chinese population, and disclosed the mediation effect of neutrophils and HDL on the relationship between HLA-DQB1 and rosacea, implying a possible correlation between rosacea and inflammatory or metabolic factors, providing hints for future studies in the mechanism of rosacea. Key messagesHLA-DQB1*03:03 allele, HLA-DQB1*04:02 allele and HLA-DQB1*03:03/05:02 genotype were significantly associated with rosacea.HLA-DQB1*03:03 allele, HLA-DQB1*05:01 allele and HLA-DQB1*03:03/06:01 genotype were positively associated with rosacea severity.Neutrophils and HDL have mediation effects on the relationship between HLA-DQB1*03:03 and risk or severity of rosacea.

Aberrant amino acid metabolism promotes neurovascular reactivity in rosacea

Rosacea is a chronic skin disorder characterized by abnormal neurovascular and inflammatory conditions on the central face. Despite increasing evidence suggesting that rosacea is associated with metabolic disorders, the role of metabolism in rosacea pathogenesis remains unknown. Here, via a targeted metabolomics approach, we characterized significantly altered metabolic signatures in patients with rosacea, especially for amino acid-related metabolic pathways. Among these, glutamic acid and aspartic acid were highlighted and positively correlated with the disease severity in patients with rosacea. We further demonstrated that glutamic acid and aspartic acid can facilitate the development of erythema and telangiectasia, typical features of rosacea, in the skin of mice. Mechanistically, glutamic acid and aspartic acid stimulated the production of vasodilation-related neuropeptides from peripheral neurons and keratinocytes and induced the release of nitric oxide from endothelial cells and keratinocytes. Interestingly, we provided evidence showing that doxycycline can improve the symptoms of patients with rosacea possibly by targeting the amino acid metabolic pathway. These findings reveal that abnormal amino acid metabolism promotes neurovascular reactivity in rosacea and raise the possibility of targeting dysregulated metabolism as a promising strategy for clinical treatment.

hMSC exosomes as a novel treatment for female sensitive skin: An in vivo study

Background: Recent studies have reported that the incidence of sensitive skin is increasing. Skin sensitivity and skin barrier functions were related to many skin diseases including atopic dermatitis, psoriasis, rosacea, and so on. Mesenchymal stem cell (MSC)-derived exosomes (hMSC) might be considered as a new effective therapeutic scheme.

Aims: This study aims to investigate the safety and efficacy of hMSC exosomes as a novel topical treatment for sensitive skin.

Patients/Methods: Exosomes were extracted from primary hMSC via ultracentrifugation method. The morphology of hMSC exosomes was studied via transmission electron microscope. Expression of exosome specific surface marker was detected via Western blot. 22 subjects (female, aged 18–55) diagnosed with sensitive skin were enrolled. Follow-up was conducted before, 7-day, 14-day, and 28-day after hMSC exosomes use. Transepidermal water loss (TEWL), surface hydration, sebum secretion, and L*a*b* value were simultaneously tested at the same time point in an environment-controlled room.

Results: Under transmission electron microscopy, the extracted hMSC exosomes were circular or elliptical with intact membrane structure, and their diameters ranged mainly from 40 to 80 nm. Western blot showed that the expression of markers CD63, CD9, and Tsg101 was positive. Brownian motion based nanoparticle trajectory analysis (NTA) showed that the main peak of particle size distribution occurred around 96 nm, the average particle size was 122 nm, and the main peak accounted for 96.7%. All this conformed to the biological characteristics of exosomes standardized by the International Society for Extracellular Vesicles. In the clinical trial, scores of objective symptoms including roughness, scales, erythema, and subjective symptoms including tension, burning, or itching, were improved after 7-, 14-, and 28- day using hMSC-exosomes. TEWL, hydration, sebum, pH, and a* values were tended to return to the level of healthy skin.

Conclusion: The hMSC-exosomes, with the advantages of biocompatibility and biodegradability, could improve clinical symptoms and eruptions in sensitive skin patients, and might be as an MSC cell-free novel therapy in sensitive skin-related disease treatment.

Clinical characteristics of combined rosacea and migraine

Background

An overlap between the skin disease rosacea and the headache disease migraine has been established; however, the magnitude of this overlap and the distribution between subtypes/phenotypes remains unclear.

Objective

The aim was to determine the magnitude of the overlap between rosacea and migraine, and to determine which subtypes/phenotypes were present in patients with concomitant rosacea and migraine.

Methods

In this cross-sectional study, 604 patients with a diagnosis of either rosacea or migraine were phenotyped through a face-to-face interview with clinical examination, to determine prevalence and phenotype of rosacea, and prevalence and subtype of migraine.

Results

We found a prevalence of migraine of 54% in patients with rosacea, and a prevalence of rosacea of 65% in patients with migraine. Concomitant migraine was significantly associated with the rosacea features flushing (odds ratio = 2.6, 95% confidence interval = 1.4–4.7, p = 0.002), ocular symptoms (odds ratio = 2.4, 95% confidence interval = 1.5–3.9, p < 0.001), and burning (odds ratio = 2.1, 95% confidence interval = 1.3–3.4, p = 0.002), whereas papules/pustules were inversely related with concomitant migraine (odds ratio = 0.5, 95% confidence interval = 0.3–0.8, p = 0.006). No association was found between concomitant migraine and centrofacial erythema, rhinophyma, telangiectasia, edema, or dryness. Concomitant rosacea was not associated with any specific migraine subtype in patients with migraine.

Conclusion

This study highlights a substantial overlap between rosacea and migraine, particularly in patients with certain rosacea features. Individuals with rosacea should be asked about concomitant migraine, and comorbidities should be considered when choosing between treatments.

A randomized split-face comparative study of long-pulsed alexandrite plus low-fluence Nd:YAG laser versus pulsed-dye laser in the treatment of rosacea

OBJECTIVES

To compare the effectiveness of long-pulsed alexandrite laser (LPAL) with that of pulsed-dye laser (PDL) for rosacea.

METHODS

This was a single-blind randomized controlled trial on 27 patients who were clinically diagnosed with rosacea. Randomly assigned split face in each patient received four times monthly treatment of LPAL plus low-fluence Nd:YAG with the contralateral side serving as the control treated with PDL. At every visit, the erythema index (EI) was measured with skin analysis systems, and two independent dermatologists evaluated digital photographs for five-point global aesthetic improvement scale (GAIS).

RESULTS

The EI significantly decreased on both treated sides (LPAL 366.5 ± 101.0 vs. 295.8 ± 90.2, p < 0.001, PDL 369.0 ± 124.3 vs. 302.7 ± 92.1, p < 0.001) 1 month after fourth treatment (visit 5). Also 3 months after the fourth treatment (visit 6), the reduction in the EI was well maintained on both sides (LPAL 360.3 ± 96.8 vs. 282.0 ± 89.2, p < 0.001, PDL 364.3 ± 121.6 vs. 281.6 ± 97.8, p < 0.001). When comparing the improvement in the EI between the two groups, the percentage reduction in the EI on the LPAL-treated side was not inferior to the PDL-treated side (visit 5: LPAL 18.7 ± 15.7% vs. PDL 16.4 ± 12.9%, p = 0.501 and visit 6: LPAL 21.7 ± 13.9% vs. PDL 21.9 ± 15.2%, p = 0.943). The GAIS and patient satisfaction were comparable between the LPAL and PDL sides and did not show any significant difference. No serious adverse events occurred on either of the treated sides.

CONCLUSION

This study showed that the decrease in EI in the treatment of rosacea was comparable between PDL and LPAL. Therefore, LPAL could be a promising alternative treatment option with good merits for rosacea, considering no consumables are required for device maintenance.

Lithocholic acid promotes rosacea-like skin inflammation via G protein-coupled bile acid receptor 1

BACKGROUND

Rosacea is a chronic inflammatory skin disorder with unclear etiology. Evidence showed that immunoinflammatory dysregulation was involved in the pathogenesis. Bile acids, as important participants of hepatoenteric circulation, play a vital role in immunoinflammatory regulation through peripheral blood circulation. However, whether it has effects on rosacea remains unknown.

METHODS

Here, we performed a bile acid analysis on the serum samples of rosacea patients and healthy controls. Then we gavage G protein-coupled bile acid receptor 1 (TGR5) knockout mice with lithocholic acid (LCA) based on a LL37-induced rosacea-like model. We further overexpress TGR5 in HaCaT keratinocytes to figure out the downstream pathway.

RESULTS

We found varied bile acid profile in the peripheral blood circulation of patients, especially the most significant increase in LCA. LCA promoted skin inflammation in LL37-induced rosacea-like mouse model. Our in vivo and in vitro results further demonstrated that LCA induced inflammatory cytokines and chemokines, thus exacerbated rosacea-like skin inflammation, via TGR5 in keratinocytes and LL37-induced rosacea-like mouse model.

CONCLUSIONS

Therefore, we conclude that LCA promotes skin inflammation of rosacea via TGR5, and LCA-TGR5 axis may be a novel therapeutic target for rosacea.

The family of kallikrein-related peptidases and kinin peptides as modulators of epidermal homeostasis

The epidermis is the outermost skin layer and is part of one of the largest organs in the body; it is supported by the dermis, a network of fibrils, blood vessels, pilosebaceous units, sweat glands, nerves, and cells. The skin as a whole is a protective shield against numerous noxious agents, including microorganisms and chemical and physical factors. These functions rely on the activity of multiple growth factors, peptide hormones, proteases, and specific signaling pathways that are triggered by the activation of distinct types of receptors sited in the cell membranes of the various cell types present in the skin. The human kallikrein family comprises a large group of 15 serine proteases synthesized and secreted by different types of epithelial cells throughout the body, including the skin. At this site, they initiate a proteolytic cascade that generates the active forms of the proteases, some of which regulate skin desquamation, activation of cytokines, and antimicrobial peptides. Kinin peptides are formed by the action of plasma and tissue kallikreins on kininogens, two plasma proteins produced in the liver and other organs. Although kinins are well known for their proinflammatory abilities, in the skin they are also considered important modulators of keratinocyte differentiation. In this review, we summarize the contributions of the kallikreins and kallikrein-related peptidases family and those of kinins and their receptors in skin homeostasis, with special emphasis on their pathophysiological role.

S2k guideline: Rosacea

This updated and upgraded S2k guideline deals with the diagnosis and treatment of rosacea, which is a common, chronic inflammatory skin disease mostly affecting the face. Initially, rosacea is characterized by recurrent erythema, telangiectasia and flushing. Later, the inflammatory component predominates, with persistent erythema with follicular papules, papulopustules and pustules. The development of phyma, which usually occurs on the acral localizations, is the most severe manifestation. For the treatment of rosacea, the interdisciplinary guideline committee, with representatives of the German Dermatological Society (DDG), the Professional Association of German Dermatologists (BVDD), the German Opthalmological Society (DOG), the Society for Dermopharmacy (GD), the Swiss Society for Dermatology and Venereology (SGDV) and the German Rosacea Aid e. V., recommends the avoidance of trigger factors and topical applications of metronidazole, azelaic acid or ivermectin. For symptomatic treatment of persistent centrofacial erythema, the topical vasoconstrictors brimonidine or oxymetazoline can also be used. Systemic therapy is recommended for therapy-resistant and severe forms of rosacea papulopustulosa. The drug of choice is low-dose doxycycline. Alternatively, low-dose isotretinoin can be recommended. Ocular rosacea should be treated with lid margin hygiene. For topical treatment, ciclosporin eye drops, azithromycin, ivermectin or metronidazole are suggested.

Differential Diagnosis of Rosacea Using Machine Learning and Dermoscopy

Introduction

Rosacea is a common chronic inflammatory disease occurring on the face, whose diagnosis is mainly based on symptoms and physical signs. Due to some overlap in symptoms and signs with other inflammatory skin diseases, young and inexperienced doctors often make misdiagnoses and missed diagnoses in clinical practices. We analyze the results of skin physiology and dermatoscopy using machine learning method and identify the characteristics of acne rosacea, which differentiate it from other common facial inflammatory skin diseases so as to improve the accuracy of clinical and differential diagnosis of rosacea.

Methods

A total of 495 patients who were jointly diagnosed by two experienced doctors were included. Basic data, clinical symptoms, physiological skin detection, and dermatoscopy results were collected, and the clinical characteristics of rosacea and other common facial inflammatory diseases were summarized according to the descriptive analysis results. The model was established using a machine learning method and compared with the judgment results of young and inexperienced doctors to verify whether the model can improve the accuracy of clinical diagnosis and differential diagnosis of rosacea.

Results

The proportion of yellow and red halos, vascular polygons, as well as follicular pustules, showed by dermatoscopy, and the melanin index in physiological skin detection revealed statistical significance in differentiating rosacea and other common facial inflammatory diseases (all P < 0.01). After adopting the machine learning, we found that GBM (Gradient Boosting Machine) algorithm was the best, and the error rate of this model in the validation set was 5.48%. In the final man-machine comparison, the accuracy of the GBM algorithm model for the classification of skin disease was significantly higher than that of young and inexperienced doctors.

Conclusion

Dermatoscopy combined with machine learning can effectively improve the diagnosis and differential diagnosis accuracy of rosacea and other facial inflammatory skin diseases.

Relationships of Serum Homocysteine, Vitamin B12, and Folic Acid Levels with Papulopustular Rosacea Severity: A Case-Control Study

Background

Rosacea is a chronic inflammatory skin disease with a multifactorial etiology. Recently, associations between serum homocysteine (Hcy) levels and inflammatory skin diseases, such as psoriasis and hidradenitis suppurativa, have been reported. However, no study has explored the levels of serum Hcy, folic acid, and vitamin B₁₂ in patients with rosacea.

Objective

To investigate serum Hcy, vitamin B₁₂, and folic acid levels in patients with papulopustular rosacea (PPR), we characterized the association of these levels with PPR severity.

Methods

This case-control study included 138 PPR patients and 58 healthy controls. The serum levels of Hcy, vitamin B₁₂, and folic acid were measured. A correlation was assessed between disease severity and serum levels of Hcy, vitamin B₁₂, and folic acid.

Results

Serum vitamin B₁₂ and folic acid levels were significantly lower in PPR patients than in the healthy controls (p = 0.011 and p = 0.0173, respectively). Although serum Hcy levels did not significantly differ between PPR patients and healthy controls, PPR severity was positively correlated with serum Hcy levels (p < 0.001).

Conclusions

Our results suggest a possible association between hyperhomocysteinemia and vitamin B₁₂ deficiency in patients with PPR.

Identifying the neural basis for rosacea using positron emission tomography‐computed tomography cerebral functional imaging analysis: A cross‐sectional study

BACKGROUND

The neural basis of rosacea is not well understood. This study aimed to determine whether cerebral glucose metabolism (CGM) changes on ¹⁸ F-fluorodeoxyglucose (¹⁸ F-FDG) positron emission tomography (PET)/computed tomography (CT) scans can detect functional network changes in specific brain areas in patients with rosacea.

MATERIALS AND METHODS

Eight adults with rosacea and 10 age/sex-matched healthy adults (controls) were enrolled in the study. ¹⁸ F-FDG PET/CT brain images for all eight patients and whole-body images for two of the patients were analyzed qualitatively and semi-quantitatively. Differences between the study groups were examined using Fischer's exact test and a Student's t-test. A voxel-based analysis using statistical parametric mapping was performed to compare the brain metabolism of the patients with that of the controls.

RESULTS

Compared with the controls, the patients with rosacea showed extensive changes in the CGM signals in the cerebral cortex and limbic system, with less CGM shown in the right superior parietal lobule, right postcentral gyrus, right parahippocampal gyrus, left superior frontal gyrus, and lateral posterior thalamic nucleus and more CGM in the right precentral gyrus, left inferior frontal gyrus, and cerebellar tonsil. No dysmetabolic lesions were found in the whole-body ¹⁸ F-FDG PET/CT images.

CONCLUSION

Specific neural functional changes occur in patients with rosacea that may explain its pathogenesis.

Roles of Epithelial and Mesenchymal TRP Channels in Mediating Inflammatory Fibrosis

The maintenance of normal vision is dependent on preserving corneal transparency. For this to occur, this tissue must remain avascular and its stromal architecture needs to be retained. Epithelial transparency is maintained provided the uppermost stratified layers of this tissue are composed of terminally differentiated non-keratinizing cells. In addition, it is essential that the underlying stromal connective tissue remains avascular and scar-free. Keratocytes are the source of fibroblasts that are interspersed within the collagenous framework and the extracellular matrix. In addition, there are sensory nerve fibers whose lineage is possibly either neural crest or mesenchymal. Corneal wound healing studies have been undertaken to delineate the underlying pathogenic responses that result in the development of opacification following chemical injury. An alkali burn is one type of injury that can result in severe and long- lasting losses in ocular transparency. During the subsequent wound healing process, numerous different proinflammatory cytokines and proteolytic enzymes undergo upregulation. Such increases in their expression levels induce maladaptive expression of sustained stromal inflammatory fibrosis, neovascularization, and losses in the smooth optical properties of the corneal outer surface. It is becoming apparent that different transient receptor potential channel (TRP) isoforms are important players in mediating these different events underlying the wound healing process since injury upregulates both their expression levels and functional involvement. In this review, we focus on the involvement of TRPV1, TRPA1 and TRPV4 in mediating some of the responses that underlie the control of anterior ocular tissue homeostasis under normal and pathological conditions. They are expressed on both different cell types throughout this tissue and also on corneal sensory nerve endings. Their roles have been extensively studied as sensors and transducers of environmental stimuli resulting from exposure to intrinsic modulators and extrinsic ligands. These triggers include alteration of the ambient temperature and mechanical stress, etc., that can induce pathophysiological responses underlying losses in tissue transparency activated by wound healing in mice losses in tissue transparency. In this article, experimental findings are reviewed about the role of injury-induced TRP channel activation in mediating inflammatory fibrotic responses during wound healing in mice.

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.

Efficacy Comparison of Pulsed Dye Laser vs. Microsecond 1064-nm Neodymium:Yttrium-Aluminum-Garnet Laser in the Treatment of Rosacea: A Meta-Analysis

Purpose

The advantage of pulsed dye laser (PDL) for the treatment of rosacea is not yet clear. This meta-analysis compared the curative effect of PDL to neodymium:yttrium-aluminum-garnet (Nd:YAG) laser for the treatment of rosacea.

Methods

The PubMed, Embase, and Cochrane Library databases were searched for clinical studies on the efficacy of PDL for the treatment of rosacea through October 13, 2021, and heterogeneity tests among studies were evaluated. Meta-analysis was conducted to combine the effects of physicians' clinical assessments, patient global assessment, erythema index, and visual analog scale.

Results

A total of 326 articles were obtained from three databases and ten articles were finally included. The clinical improvements of >50% clearance of up to 68.6% in the PDL group and 71.4% in the control group, and the subjective satisfaction rate of patients in the PDL group of 88.6% compared to 91.4% in the Nd:YAG group, but there were no significant differences in the rates of patients with rosacea with clinical improvement (>50% clearance) (relative risk [RR] = 0.94, 95% confidence interval [CI]: 0.75–1.17, P = 0.578) or patient subjective satisfaction rate (RR = 0.96, 95% CI: 0.70–1.33, P = 0.808) between PDL and Nd:YAG groups for rosacea treatment. Also, the pain score for PDL and Nd:YAG were not significant (mean = 3.07, 95% CI: 1.82–4.32, P = 0.115).

Conclusion

Two treatments all showed clinical efficacy and patient satisfaction for the treatment of rosacea, with no significant differences observed between treatments. The pain scores for PDL and Nd:YAG were not significant.

mTORC1-Mediated Angiogenesis is Required for the Development of Rosacea

Although multiple evidences suggest that angiogenesis is associated with the pathophysiology of rosacea, its role is still in debate. Here, we showed that angiogenesis was enhanced in skin lesions of both rosacea patients and LL37-induced rosacea-like mice. Inhibition of angiogenesis alleviated LL37-induced rosacea-like features in mice. Mechanistically, we showed that mTORC1 was activated in the endothelial cells of the lesional skin from rosacea patients and LL37-induced rosacea-like mouse model. Inhibition of mTORC1 decreased angiogenesis and blocked the development of rosacea in mice. On the contrary, hyperactivation of mTORC1 increased angiogenesis and exacerbated rosacea-like phenotypes. Our in vitro results further demonstrated that inhibition of mTORC1 signaling significantly declined LL37-induced tube formation of human endothelial cells. Taken together, our findings revealed that mTORC1-mediated angiogenesis responding to LL37 might be essential for the development of rosacea and targeting angiogenesis might be a novel potential therapy.

The Effect of Capsaicin on Neuroinflammatory Mediators of Rosacea

Background

Rosacea is a chronic inflammatory skin disease with a pathophysiological mechanism that remains unclear. Recently, dysregulation of the sensory nerve system has been implicated in the development of this condition.

Objective

This study aimed to investigate the effect of capsaicin on neuroinflammatory mediators in rosacea. In addition, this study aimed to evaluate the attenuating effects of capsazepine, a transient receptor potential vanilloid type 1 (TRPV1) antagonist.

Methods

We obtained skin tissue from both rosacea patients and normal individuals for an in vivo study. In addition, normal human epidermal keratinocytes (NHEKs) were cultured, and treated with capsaicin and capsazepine for an in vitro study. Quantitative changes in neuroinflammatory mediators were evaluated by semi-quantitative reverse transcription-polymerase chain reaction (PCR), real-time PCR, enzyme-linked immunosorbent assay, and immunofluorescence staining.

Results

The data showed the increase of TRPV1, TRPV4, cathelicidin (LL37) and tumor necrosis factor-α (TNF-α) in skin tissue by real-time PCR. In addition, the data showed that cathelicidin (LL37), kallikrein-5 (KLK-5), TNF-α, vascular endothelial growth factor (VEGF), interleukin (IL)-1α, IL-1β, IL-8, and protease-activated receptor 2 (PAR2) increased in capsaicin-treated NHEKs. Capsazepine attenuated the expression of TRPV1 and other mediators, except for IL-8, in capsaicin-treated NHEKs.

Conclusion

We confirmed that TRPV1, TRPV4, cathelicidin (LL37) and TNF-α are increased in rosacea skin, and that capsaicin is associated with increase of neuroinflammatory mediators such as LL37, KLK-5, TNF-α, VEGF, IL-1α, IL-1β, IL-8, and PAR2. Modulators or inhibitors of neuroinflammatory mediators including TRPV1 could be potential therapeutic option in the treatment of patients with rosacea.

Exploring metformin as a candidate drug for rosacea through network pharmacology and experimental validation

Rosacea is a common chronic inflammatory disease that affects the middle of the face. Due to the unclear pathogenesis, the effective treatment options for rosacea remain limited. In this study, weighted gene co-expression network analyses (WGCNA) identified three rosacea-related hub modules, which were involved in immune-, metabolic- and development- related signaling pathways. Next, the key genes from green and brown modules were submitted to CMap database for drug prediction and metformin was identified as a candidate drug for rosacea. Moreover, network pharmacology analysis identified pharmacological targets of metformin and demonstrated that metformin could help in treating rosacea partly by modulating inflammatory and angiogenesis signaling pathways. Finally, we verified the therapeutic role and mechanism of metformin on rosacea in vivo and vitro. We found that metformin treatment significantly improved rosacea-like skin lesions including immune cells infiltration, cytokines/chemokines expression and angiogenesis. Moreover, metformin suppressed LL37- and TNF-α-induced the ROS production and MAPK-NF-κB signal activation in keratinocytes cells. In conclusion, our findings identified and verified metformin as a novel therapeutic candidate for rosacea, and it alleviates the pathological symptoms, possibly by suppressing inflammatory responses, angiogenesis in rosacea.

Angiogenesis in Chronic Inflammatory Skin Disorders

Angiogenesis, the growth of new blood vessels from preexisting vessels, is associated with inflammation in various pathological conditions. Well-known angiogenetic factors include vascular endothelial growth factor (VEGF), angiopoietins, platelet-derived growth factor, transforming growth factor-β, and basic fibroblast growth factor. Yes-associated protein 1 (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ) have recently been added to an important angiogenic factor. Accumulating evidence indicates associations between angiogenesis and chronic inflammatory skin diseases. Angiogenesis is deeply involved in the pathogenesis of psoriasis. VEGF, angiopoietins, tumor necrosis factor-a, interleukin-8, and interleukin-17 are unregulated in psoriasis and induce angiogenesis. Angiogenesis may be involved in the pathogenesis of atopic dermatitis, and in particular, mast cells are a major source of VEGF expression. Angiogenesis is an essential process in rosacea, which is induced by LL-37 from a signal cascade by microorganisms, VEGF, and MMP-3 from mast cells. In addition, angiogenesis by increased VEGF has been reported in chronic urticaria and hidradenitis suppurativa. The finding that VEGF is expressed in inflammatory skin lesions indicates that inhibition of angiogenesis is a useful strategy for treatment of chronic, inflammatory skin disorders.