Granulomatous rosacea and Crohn's disease in a patient homozygous for the Crohn-associated NOD2/CARD15 polymorphism R702W

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.

Association between metabolites in tryptophan-kynurenine pathway and inflammatory bowel disease: a two-sample Mendelian randomization

Previous observational studies have suggested an association between tryptophan (TRP)-kynurenine (KYN) pathway and inflammatory bowel disease (IBD). However, whether there is a causal relationship among them remains unclear. Therefore, a two-sample Mendelian randomization (MR) study was conducted to explore the potential causal effects of crucial metabolites in TRP-KYN pathway on IBD and its subtypes. Using summary data from genome-wide association studies, a two-sample MR was employed to evaluate the genetic associations between TRP and KYN as exposures and IBD as an outcome. The inverse variance weighted method was used as the primary MR analysis, with MR-Egger, weighted mode, simple mode, and weighted median methods as complementary analyses. The odds ratios (OR) and 95% confidence intervals (CI) were determined for TRP-IBD (OR 0.739, 95% CI [0.697; 0.783]), TRP-UC (OR 0.875, 95% CI [0.814; 0.942]), TRP-CD (OR 0.685, 95% CI [0.613; 0.765]), KYN-IBD (OR 4.406, 95% CI [2.247; 8.641]), KYN-UC (OR 2.578, 95% CI [1.368; 4.858], and KYN-CD (OR 13.516, 95% CI [4.919; 37.134]). Collectively, the MR analysis demonstrated a significant protective association between TRP and IBD, whereas KYN was identified as a risk factor for IBD.

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.

Mechanisms of rosacea pathogenesis. A phenotypic approach to therapeutic tactics

Rosacea is a widespread disease worldwide, affecting 5.5% of the human population and accompanied by a significant deterioration in the patient's quality of life. Currently, there are two classifications of rosacea, the first of which is based on a subtype approach (erythematous-telangiectatic, papulo-pustular, phimatous and ophthalmological subtypes), or on an individual analysis of the presented phenotype of rosacea. New data on the pathophysiology of rosacea have emerged, which show that genetic factors and environmental components can cause the initiation and exacerbation of rosacea due to a violation of the regulation of the innate and adaptive immune system. In addition, trigger factors can directly interact with the cutaneous nervous system and, with the help of neurovascular and neuroimmune active neuropeptides, lead to the manifestation of rosacea foci. The main mechanisms of rosacea pathogenesis are currently: activation of the immune system, disorders of neuro-immune regulation, genetic predisposition. New pathogenetic mechanisms of rosacea make it possible to continue the diagnostic search and therapeutic approaches with the personalization of management tactics for each patient, depending on the prevalence of clinical features of the course of the disease. It is necessary to evaluate the advantages and disadvantages of subtypical and phenotypic approaches to rosacea classification and choose the most optimal one. The article presents arguments on this issue, and also suggests assessing the need to switch to a new classification in order to improve the effectiveness of therapy and improve the quality of life of patients.

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.

Consensus on the therapeutic management of rosacea - Brazilian Society of Dermatology

BACKGROUND

Rosacea is a chronic inflammatory disease of the skin, relatively more frequent in women over 30 with a low phototype and proven genetic predisposition. Although its etiology is unknown and possibly multifactorial, the immunological abnormality, associated with neurovascular dysregulation and triggering factors, are important elements in its pathophysiology, which lead to the main changes of inflammation, vasodilation, and angiogenesis that are responsible for the clinical manifestations. Despite the lack of cure, numerous therapeutic options are available for the different clinical presentations of the disease, with satisfactory responses.

OBJECTIVE

To reach a consensus, with recommendations from experts, on the therapeutic management of rosacea suitable to the Brazilian setting.

METHODS

The study was conducted by five specialized dermatologists from university centers, representatives of the different Brazilian regions, with experience in rosacea, who were appointed by the Brazilian Society of Dermatology. Based on the adapted DELPHI methodology, the experts contributed through an updated bibliographic review of the scientific evidence, combined with personal experiences.

RESULTS

The group of experts reached a consensus on the relevant aspects in the therapeutic management of rosacea, providing information on epidemiology, pathophysiology, triggering factors, clinical condition, classification, quality of life, and comorbidities. Consensus was defined as approval by at least 90% of the panel.

CONCLUSION

Despite the impossibility of cure, there are several therapeutic alternatives specific to each patient that provide excellent results, with chances of total improvement and long periods of remission, promoting a positive impact on quality of life. This consensus provides detailed guidance for clinical practice and therapeutic decisions in rosacea.

Relationship between rosacea and sleep

Rosacea is a chronic facial skin disease involved in neurovascular dysregulation and neurogenic inflammation. Behavioral factors such as stress, anxiety, depression and sleep were identified to be associated with other inflammatory skin diseases. Few studies have reported sleep status in rosacea. Aiming to investigate the relationship between rosacea and sleep, a case-control survey was conducted, enrolling 608 rosacea patients and 608 sex- and age-matched healthy controls. Sleep quality was assessed through the Pittsburgh Sleep Quality Index (PSQI) questionnaire. Diagnosis and severity grading of rosacea were evaluated under the standard guidelines of the National Rosacea Society. More rosacea patients (52.3%, n = 318) suffered poor sleep quality (PSQI, >5) than the healthy controls (24.0%, n = 146), displaying a much higher PSQI score (rosacea vs control, 6.20 vs 3.95). There was a strong association between sleep quality and rosacea (odds ratio [OR], 3.525; 95% confidence interval [CI], 2.759-4.519). Moreover, the severity of rosacea was also associated with sleep quality (OR, 1.847; 95% CI, 1.332-2.570). Single nucleotide polymorphisms in hydroxytryptamine receptor 2A and adrenoceptor-β1 genes, which are associated with sleep behaviour, were detected and revealed to be associated with rosacea. Furthermore, the LL-37-induced rosacea-like phenotype and sleep-deprivation mice models were applied, revealing that sleep deprivation aggravated the rosacea-like phenotype in mice, with higher expression of matrix metallopeptidase 9, Toll-like receptor 2, cathelicidin antimicrobial peptide and vascular endothelial growth factor. In conclusion, rosacea patients presented poorer sleep quality, as well as a higher propability of genetic background with sleep disturbance. In addition, poor sleep might aggravate rosacea through regulating inflammatory factors, contributing to a vicious cycle in the progression of disease.

Association of rosacea with inflammatory bowel disease: A MOOSE-compliant meta-analysis

Rosacea has been reported with several systemic comorbidities, but its relationship with inflammatory bowel disease (IBD) is unclear. Thus, our objective is to conduct a meta-analysis on the association of rosacea with IBD.We conduct a meta-analysis and searched MEDLINE, CENTRAL, and Embase databases for case-controlled and cohort studies that assessed the association of rosacea with IBD from inception to July 2nd, 2018. Two authors independently selected studies, extracted data, and assessed the risk of bias of included studies. Disagreement was resolved by discussion. We performed random-effects model meta-analysis to obtain the pooled risk estimates for Crohn disease (CD) and ulcerative colitis (UC) in patients with rosacea.We included three case-control and three cohort studies. The risk of bias of included studies was generally low. The meta-analysis on case-control studies showed marginally increased odds of CD (pooled odds ratio (OR) 1.30, 95% confidence interval (CI) 0.99-1.69) and a significantly increased odds of UC (pooled OR 1.64, 95% CI 1.43-1.89) in patients with rosacea. The meta-analysis on cohort studies demonstrated significant increased risk of CD (pooled hazard ratio (HR) 1.58, 95% CI 1.14-2.20) and UC (pooled HR 1.18, 95% CI 1.01-1.37) in patients with rosacea.The evidence indicates an association of rosacea with IBD. If patients with rosacea suffer from prolonged abdominal pain, diarrhea, and bloody stool, referral to gastroenterologists may be considered.

Recent advances in understanding and managing rosacea

Rosacea is a common chronic inflammatory skin disease of the central facial skin and is of unknown origin. Currently, two classifications of rosacea exist that are based on either "preformed" clinical subtypes (erythematotelangiectatic, papulopustular, phymatous, and ocular) or patient-tailored analysis of the presented rosacea phenotype. Rosacea etiology and pathophysiology are poorly understood. However, recent findings indicate that genetic and environmental components can trigger rosacea initiation and aggravation by dysregulation of the innate and adaptive immune system. Trigger factors also lead to the release of various mediators such as keratinocytes (for example, cathelicidin, vascular endothelial growth factor, and endothelin-1), endothelial cells (nitric oxide), mast cells (cathelicidin and matrix metalloproteinases), macrophages (interferon-gamma, tumor necrosis factor, matrix metalloproteinases, and interleukin-26), and T helper type 1 (T _H1) and T _H17 cells. Additionally, trigger factors can directly communicate to the cutaneous nervous system and, by neurovascular and neuro-immune active neuropeptides, lead to the manifestation of rosacea lesions. Here, we aim to summarize the recent advances that preceded the new rosacea classification and address a symptom-based approach in the management of patients with rosacea.

Rosacea: Molecular Mechanisms and Management of a Chronic Cutaneous Inflammatory Condition

Rosacea is a chronic cutaneous inflammatory disease that affects the facial skin. Clinically, rosacea can be categorized into papulopustular, erythematotelangiectatic, ocular, and phymatous rosacea. However, the phenotypic presentations of rosacea are more heterogeneous. Although the pathophysiology of rosacea remains to be elucidated, immunologic alterations and neurovascular dysregulation are thought to have important roles in initiating and strengthening the clinical manifestations of rosacea. In this article, we present the possible molecular mechanisms of rosacea based on recent laboratory and clinical studies. We describe the genetic predisposition for rosacea along with its associated diseases, triggering factors, and suggested management options in detail based on the underlying molecular biology. Understanding the molecular pathomechanisms of rosacea will likely aid toward better comprehending its complex pathogenesis.

Rosacea, Use of Tetracycline, and Risk of Incident Inflammatory Bowel Disease in Women

BACKGROUND & AIMS

Rosacea is an inflammatory skin disease. Case reports have shown rosacea as a comorbidity of inflammatory bowel disease (IBD), but no epidemiologic studies have examined rosacea and risk of subsequent IBD. The association between tetracycline use and risk of IBD was assessed, but this study produced limited findings. We examined the association between rosacea, use of tetracycline, and risk of incident Crohn's disease (CD) and ulcerative colitis (UC).

METHODS

We analyzed data from 96,314 participants in the Nurses' Health Study II (1991-2011). Information on IBD was confirmed by medical review. Participants were asked in 2005 about their lifetime histories of clinician-diagnosed rosacea and year of diagnosis. Information on ever use of tetracycline was collected in 1993.

RESULTS

During 1,856,587 person-years (1991-2011), we identified 149 cases of CD and 215 cases of UC. Rosacea was not associated with risk of UC. In contrast, rosacea was significantly associated with increased risk of subsequent CD (hazard ratio [HR], 2.20; 95% confidence interval [CI], 1.15-4.18), which appeared particularly stronger for a longer duration after a diagnosis of rosacea (Ptrend = .01). Tetracycline use was associated with increased risk of CD (HR, 1.56; 95% CI, 1.09-2.24) and UC (HR, 1.34; 95% CI, 1.00-1.80); there was a trend toward increased risk with increased duration of use (both Ptrend < .05) (1993-2011).

CONCLUSIONS

On the basis of an analysis of data from the Nurses' Health Study II, ever use of tetracycline at baseline is associated with an increased risk of CD and UC. Personal history of rosacea is associated with an increased risk of only CD.

Assessment of Tachykinin Receptor 3' Gene Polymorphism rs3733631 in Rosacea

Background. Rosacea is a chronic skin disease, possibly following the neurogenic skin inflammation model. Neurokinin B, involved in the pathogenesis of Parkinson's disease, frequently coexisting with subsequent onset of rosacea, is an endogenous ligand of the tachykinin receptor 3 (TACR3). Methods. 128 rosacea patients and 121 matched controls were genotyped for rs3733631 by PCR-RFLP and analyzed by chi-square test. Results. We observed statistically significant predominance of the C/G or G/G genotype (p = 0.006) and of the G allele (p = 0.004) in the papulopustular (PP) form of rosacea and statistically marginal significance of the C/G or G/G genotype in erythematotelangiectatic (ET) rosacea (p = 0.052). Significantly higher frequency of the C/G or G/G genotype and G allele in PP rosacea (p = 0.021 and p = 0.008, resp.) was ascertained within male patients. Conclusion. TACR3 rs3733631 G allele possibly predisposes the evolution of the initial phase of rosacea to the PP and not the ET form in male patients.

Autoinflammation: From monogenic syndromes to common skin diseases

Autoinflammation is characterized by aberrant regulation of the innate immune system and often manifests as periodic fevers and systemic inflammation involving multiple organs, including the skin. Mutations leading to abnormal behavior or activity of the interleukin 1 beta (IL-1ß)-processing inflammasome complex have been found in several rare autoinflammatory syndromes, for which anticytokine therapy such as IL-1 or tumor necrosis factor-alfa inhibition may be effective. It is becoming clear that features of autoinflammation also affect common dermatoses, some of which were previously thought to be solely autoimmune in origin (eg, vitiligo, systemic lupus erythematosus). Recognizing the pathogenetic role of autoinflammation can open up new avenues for the targeted treatment of complex, inflammatory dermatoses.

Rethinking the prosaicism of mosaicism; is it in us?

Exponential advances in the quantitation of DNA variation and epigenetic states seem poised to convert much of biological research into a statistical exercise. But these developments also invite us to reimagine well-worn biological concepts on a grander scale. Somatic mosaicism refers to postzygotic mutations persisting in the individual, occasionally conspicuous to dermatologists as Blaschkoid, checkerboard, phylloid and patchy morphologies. A thoughtful examination of cutaneous mosaicism suggests, however, that virtually all of us may be somatic mosaics. Such genetic variability within individuals might explain localized presentations of disease and implies that some tissues literally evolve throughout life. We discuss here (i) the likely ubiquity of somatic mosaicism, (ii) the broad range of possible biological consequences and (iii) how experimentalists and clinicians may begin establishing genotype-to-phenotype correlates.

Role of negative regulators of TLR/IL-1 signaling in the pathogenesis of inflammatory bowel disease

Inflammatory bowel disease (IBD) is an autoimmune-like disorder characterized by chronic, idiopathic inflammation of the intestinal mucosa. Ulcerative colitis and Crohn's disease are known as the two forms of IBD. Although the etiology of IBD is still unclear, many experimental and clinical observations suggest the involvement of environmental, hereditary and immunological factors in the pathogenesis of IBD. Recent studies have showed that IBD is associated with immunologic dysfunction. Toll-like receptors (TLR) are pathogen pattern recognition receptors expressed by immune and nonimmune cells in the intestinal mucosa that play a central role in the initiation of innate immune responses and subsequent adaptive immune responses to microbial pathogens. In recent years there has been rapid progress in our understanding of the role of positive regulation of TLR signaling in the pathogenesis of IBD. However, the role of negative regulators of TLR signaling in this process remains unclear and will therefore be summarized in this paper.