Rosacea is a chronic inflammatory skin disease characterized by recurrent erythema, flushing, telangiectasia, papules, pustules, and phymatous changes in the central area of the face. Patients with this condition often experience a significant negative impact on their quality of life, self-esteem, and overall well-being. Despite its prevalence, the pathogenesis of rosacea is not yet fully understood. Recent research advances are reshaping our understanding of the underlying mechanisms of rosacea, and treatment options based on the pathophysiological perspective hold promise to improve patient outcomes and reduce incidence. In this comprehensive review, we investigate the pathogenesis of rosacea in depth, with a focus on emerging and novel mechanisms, and provide an up-to-date overview of therapeutic strategies that target the diverse pathogenic mechanisms of rosacea. Lastly, we discuss potential future research directions aimed at enhancing our understanding of the condition and developing effective treatments.

Background: We previously found that modified 5-aminolevulinic acid photodynamic therapy (M-PDT) is painless and effective in cutaneous squamous cell carcinoma (cSCC) treatment, however, the regulatory mechanism of M-PDT in cSCC is still unclear.Objective: To clarify the effect and relevant regulatory mechanism of M-PDT in cSCC.Methods: The cSCC apoptosis was examined by flow cytometry, TUNEL staining and Cleaved-caspase-3 immunofluorescence, respectively. The autophagy-related characterization was detected by monodansylcadaverine (MDC) staining, transmission electron microscopy (TEM), GFP-LC3B autophagic vacuoles localization and mRFP-EGFP tandem fluorescence-tagged LC3B construct, respectively. The expression of autophagy-related proteins and Akt/mTOR signaling molecules were examined by Western blot. ROS generation was measured by DCFH-DA probe.Results: We found that M-PDT induced cSCC apoptosis in a dose-dependent manner, and this result was related to autophagic flux blockage. The phenomenon is confirmed by the results that M-PDT could induce autophagosomes accumulation and upregulate LC3-II and p62 expression. M-PDT elevated co-localization of RFP and GFP tandem-tagged LC3B puncta in cSCC cell, reflecting autophagic flux blockage, and this was confirmed by transmission electron microscopy. Furthermore, we noticed that M-PDT induced accumulated autophagosomes-dependent apoptosis via targeting ROS-mediated Akt/mTOR signaling. Suppression of Akt potentiated M-PDT-induced upregulation of LC3-II and p62 levels, whereas Akt activation and ROS inhibition rendered resistance to these events. In addition, we observed that lysosomal dysfunction was involved in M-PDT-triggered accumulated autophagosomes-dependent cSCC apoptosis.Conclusion: Our data demonstrates that M-PDT inhibits cSCC through blocking Akt/mTOR-mediated autophagic flux.

Seborrhea poses a common cosmetic concern in adolescents and young adults, often accompanied by enlarged pores, and contributing to various skin conditions, including acne vulgaris and seborrheic dermatitis. At present, there is a lack of effective treatment for this problem, and the potential of photodynamic therapy (PDT) in reducing sebum remains inconclusive. This exploratory, prospective, single-center, double-blinded, randomized split-face controlled trial aimed to compare the efficacy and safety of intense pulsed light-photodynamic therapy (IPL-PDT) versus IPL therapy for seborrhea. Participants with seborrhea underwent 3 times of IPL treatment (590nm, 15-17J/cm² based on patient's tolerance) for one hemifacial part and IPL-PDT treatment for the other. Follow-up assessment was conducted up to 8 weeks after the final treatment. Compared with single IPL treatment, IPL-PDT can significantly inhibit sebum secretion and decrease pore size. PDT group exhibited no additional damage to the skin barrier, with even lower transepidermal water loss (TEWL). Additionally, the PDT group showed superior improvement in scores of porphyrins, red areas, and ultraviolet (UV) spots. Both groups experienced only mild topical adverse effects, well tolerated by the participants. IPL-PDT is a more effective method than IPL in the treatment of seborrhea, as well as on the improvement of the skin barrier function.