Rosacea is a chronic inflammatory skin disorder of multifactorial pathogenesis, in which dysregulated innate immunity, neurovascular dysfunction, oxidative stress, and microbiome imbalance are central contributors. Recent molecular studies have revealed altered cytokine expression (e.g., IL-1β, IL-6, IL-36 family), aberrant activation of signaling pathways (STAT3, NF-κB, MAPKs), and enhanced expression of innate immune receptors such as TLR2,b TLR4, and TLR7, all of which promote chronic inflammation, angiogenesis, and barrier dysfunction. This systematic review was performed according to PRISMA guidelines. A total of 1425 records were retrieved from PubMed, Scopus, and Web of Science, and 14 studies met the inclusion criteria. The included studies comprised both clinical cohorts and translational experimental investigations using human samples. Reported findings consistently confirmed systemic and tissue-specific inflammatory activity, with elevated circulating monocytes, indoleamine 2,3-dioxygenase, and inflammatory indices, as well as tissue expression of STAT3, NF-κB, MAPKs, and cathelicidin fragments. Oxidative stress markers (TOS, OSI, AOPP, MMP-9) and hypoxia-related molecules (HIF-1α) were significantly increased in patients, correlating with disease severity and vascular manifestations. Taken together, these results highlight that rosacea involves both cutaneous and systemic molecular alterations. The evidence identifies multiple biomarkers with diagnostic potential and provides mechanistic insights into immune, vascular, and metabolic dysregulation. Future research should aim to validate these findings in larger cohorts, establish standardized biomarker panels, and explore novel therapeutic strategies targeting key molecular pathways.

Seborrheic dermatitis (SD) is a chronic inflammatory skin disorder with a multifactorial pathogenesis involving immune dysregulation, oxidative stress, neuroendocrine signaling, and alterations of the epidermal barrier–lipid axis. Increasing molecular evidence indicates that SD is associated with both systemic and cutaneous abnormalities, including elevated β-endorphin levels, disturbed redox homeostasis, enhanced lipid peroxidation, dysregulated cytokine signaling, and genetic and epigenetic susceptibility factors. This systematic review was conducted in accordance with PRISMA guidelines. Comprehensive literature searches of PubMed, Scopus, and Web of Science identified eight studies that met the inclusion criteria. The included investigations comprised clinical case–control studies, genetic and epigenetic analyses, and multi-omics profiling of human blood and skin samples. Collectively, the findings demonstrate consistent systemic oxidative and neuroendocrine alterations alongside pronounced local immune activation characterized by Th1- and Th17-skewed responses, cytokine and stress-ligand upregulation, and activation of inflammatory signaling pathways. Genetic association signals and disease-specific microRNA profiles further implicate post-transcriptional regulation of immune and keratinocyte-related pathways in SD pathogenesis. Moreover, multi-omics studies revealed coordinated immune activation accompanied by impaired epidermal barrier function and altered lipid metabolism, supporting a dysregulated immune–barrier–lipid axis. Overall, SD emerges as a disorder driven by interconnected systemic and cutaneous molecular mechanisms. The identified pathways may represent promising directions for future biomarker research and targeted therapeutic development rather than established diagnostic or treatment strategies.

Lichen sclerosus (LS) is a chronic inflammatory skin disorder with an incompletely understood molecular pathogenesis. This systematic review aimed to synthesize current evidence on key molecular mechanisms underlying the disease, with a particular focus on immune dysregulation, epigenetic modifications, and tissue remodeling. A structured literature search identified studies employing transcriptomic, epigenetic, and experimental approaches. The strongest evidence consistently supports a central role of immune activation, particularly T cell-mediated responses involving Th1- and Th17-related pathways, accompanied by increased expression of pro-inflammatory cytokines and activation of the NF-κB signaling pathway. Epigenetic and post-transcriptional mechanisms, including dysregulated microRNAs (notably miR-155-5p) and altered DNA methylation patterns, may sustain immune imbalance and fibroblast activation partly via modulation of the FOXO signaling pathway. In parallel, experimental and multi-omics studies highlight enhanced fibroblast activity and extracellular matrix remodeling, largely associated with the TGF-β signaling pathway, linking inflammation with progressive fibrosis. Emerging data also suggest interactions between immune signaling and metabolic alterations, although these findings remain preliminary. Overall, the available evidence indicates that LS may involve a complex interplay between immune, epigenetic, and fibrotic mechanisms. While several molecular pathways and candidate biomarkers have been identified, their clinical relevance requires further validation in larger, well-designed studies.

Background: Rosacea is a chronic inflammatory dermatosis characterized by vascular dysregulation, immune dysfunction, neurovascular alterations, and microbial involvement. Recent advances in understanding its pathophysiology have led to the development of targeted therapeutic strategies addressing multiple disease mechanisms. This systematic review aimed to evaluate contemporary evidence regarding emerging and established treatment approaches for rosacea. Methods: A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PubMed, Scopus, and Web of Science were searched for studies published between 2016 and 2025. Original human studies evaluating therapeutic interventions for rosacea were included. Study selection, data extraction, and risk-of-bias assessment were performed independently by two reviewers. Methodological quality was assessed using Joanna Briggs Institute (JBI) critical appraisal tools appropriate for each study design. Results: Fifteen studies involving 537 patients with rosacea and 77 controls (614 participants in total) met the eligibility criteria. Evaluated interventions included vascular-targeted therapies, topical anti-inflammatory agents, systemic and immunomodulatory treatments, and microbiome-oriented approaches. Oxymetazoline, pulsed-dye laser, platelet-rich plasma, ivermectin, azelaic acid, dapsone, sulfur preparations, and metronidazole demonstrated clinical benefits in reducing erythema, inflammatory lesions, or overall disease severity. Emerging therapies, including tofacitinib and oral ivermectin, showed promising results in refractory disease. Microbiome-related interventions, particularly Demodex-targeted therapies and Helicobacter pylori eradication, were also associated with clinical improvement. Risk-of-bias assessment identified two studies with low risk of bias, twelve with moderate risk of bias, and one study with high risk of bias. Conclusions: Current evidence supports a multimodal and mechanism-based approach to rosacea management, integrating vascular, inflammatory, immunological, and microbiological targets. However, the available evidence remains limited by small sample sizes, heterogeneous methodologies, short follow-up periods, and a predominance of non-randomized study designs. Large, well-designed randomized controlled trials are needed to establish optimal evidence-based treatment strategies and define the long-term efficacy and safety of emerging therapies.