Cutibacterium acnes is a common skin bacterium that inhabits sebaceous follicles and comprises multiple phylotypes. Healthy skin is colonized by a C. acnes population dominated by phylotypes IA, IB, and II. In acne, this diversity is reduced, with a predominance of phylotype IA. Quantifying C. acnes phylotypes has been challenging due to the lack of specific methods. Here, we developed a droplet digital PCR (ddPCR) assay that separately quantifies phylotype IA and phylotypes IB/II, based on a difference in the hyaluronidase gene. The method was applied to skin swabs from 14 healthy individuals and 14 acne patients. Healthy skin contained nearly equal amounts of IA and IB/II, whereas acne samples showed a 111-fold predominance of IA over IB/II, due to a marked depletion of IB/II, instead of an increase of IA. After 4-6 months of isotretinoin treatment, C. acnes levels decreased drastically, with phylotype IA reduced by 50-fold. Twelve to 15 months after treatment, both phylotypes rebounded, although IB/II recovered only partially. Taken together, this ddPCR method can quantitatively distinguish the acne-dominant phylotype IA from healthy skin-associated phylotypes IB/II, and is thus a useful tool for skin microbiome studies and specifically for assessing C. acnes dysbiosis in acne.

Acne vulgaris, driven by Propionibacterium acnes infection, is poorly addressed by conventional phototherapy due to oxygen dependence, transient efficacy, and pro-inflammatory side effects. Herein, we design a ternary coordination polymer (Fe-SASP/ART) that overcomes these limitations while promoting keratinocyte proliferation. The first formed Fe-sulfasalazine (SASP) precursors exhibit photothermal and photodynamic properties via ligand-to-metal charge transfer (LMCT). Artemisinin (ART) serves as coordinating ligands and structural inducers, transforming amorphous precursors into crystalline frameworks. The ART-directed architecture enables oxygen-independent carbon-centered radical generation via Fe[2] [+]-catalyzed ART cleavage (Fe[2+] generated from LMCT), establishing a dual-channel energy dissipation pathway that enhances photothermal and photodynamic performance. Notably, the iron-mediated activation of ART establishes a self-sustaining Fe[3+]/Fe[2+] redox cycle, driving prolonged radical production post-irradiation for sustained antibacterial effect. The nanoplatform achieves 69.5% bactericidal efficacy against P. acnes upon NIR irradiation, suppresses pro-inflammatory cytokines via SASP, and promotes keratinocyte proliferation (120.9% viability) through hormesis. Ex vivo studies confirm efficient follicular accumulation of the nanoplatform with controlled penetration depth. In mouse acne models, a single topical treatment with NIR irradiation elicits sustained lesion resolution over 5 days, with potent therapeutic efficacy, anti-inflammatory effects, and excellent biocompatibility. This work offers a promising paradigm for safe and effective acne management.

Acne is a common inflammatory skin condition and frequently leads to long-term adverse clinical outcomes including scarring and pigmentation, negatively impacting Health Related Quality of Life (HRQoL). Monitoring of acne progression can improve understanding of lesion evolution, support evaluation of treatment response and provide potential biomarkers for future investigation of acne sequelae. This study presents a multi-functional optical coherence tomography (OCT) protocol integrating structural imaging, OCT-based angiography (OCTA), and optical coherence elastography (OCE) for longitudinal in vivo monitoring of acne. Thirteen lesions were evaluated across eight time points over 18 days. Quantitative parameters, including Young's modulus and vascular metrics, captured biomechanical and microvascular changes during acne evolution. The system enables continuous multimodal assessment, showing that stiffness and vascular alterations reflect lesion progression. This pilot longitudinal study establishes a quantitative foundation for dermatological research and suggests that multimodal OCT monitoring may provide biomarkers for assessing lesion progression and long-term clinical outcomes.

Dietary patterns associated with high glycemic load and recurrent postprandial glucose excursions may influence skin physiology through mechanisms involving oxidative stress, insulin-IGF-1 signaling, chronic low-grade inflammation, and advanced glycation end product (AGE) formation. Disturbances in glucose homeostasis have been associated with alterations in epidermal barrier integrity, sebaceous gland activity, extracellular matrix remodeling, and tissue repair processes. These mechanisms have been investigated primarily in relation to several dermatological conditions, particularly acne vulgaris, impaired wound healing, xerosis, and skin aging. This narrative review summarizes current evidence regarding the relationship between glycemic dysregulation and skin health, with emphasis on metabolic and molecular pathways potentially involved in cutaneous dysfunction. To reflect the current strength of evidence, mechanistic studies, observational studies, and clinical investigations are distinguished throughout this review whenever possible. Particular focus is placed on postprandial glycemic variability, oxidative stress, hormonal signaling, and glycation-related tissue damage. Current evidence supports biologically plausible associations between metabolic dysregulation and several aspects of skin dysfunction, although direct evidence specifically addressing glycemic variability remains limited. Most available studies are observational or mechanistic in nature, and relatively few clinical investigations have evaluated dermatological outcomes directly. Further research is needed to clarify the clinical relevance of glycemic-targeted dietary and metabolic interventions in dermatology.

Post-inflammatory hyperpigmentation (PIH) results from inflammatory responses that leave persistent dark spots around pores after acne lesions are resolved. This pigmentation is caused by increased melanogenesis in melanocytes stimulated by acne-causing bacteria, followed by phagocytosis of excess melanin by macrophages that remain in the dermis. Therefore, to eliminate PIH caused by acne, it is essential not only to suppress excessive melanin synthesis by melanocytes but also to promote the degradation of melanin retained within macrophages. In this study, we investigated whether a culture extract of Bacillus velezensis AmoreLumina (AL), containing more than 80% moranoline (1-Deoxynojirimycin), could inhibit acne-induced pigmentation. Moranoline reduces melanin synthesis by inhibiting the glycosylation of tyrosinase, a key melanogenic enzyme, thereby suppressing its activity. The extract suppressed the upregulation of melanogenic enzymes (tyrosinase, TRP1, and TRP2) and melanin production in melanocytes exposed to acne bacteria, while promoting melanin degradation via macrophage lysosomal activity, as assessed by the relative protein expression level of p62 using Western blotting. Furthermore, in an ex vivo human skin model subjected to acne and ultraviolet radiation-induced pigmentation, treatment with the extract (0.2%) significantly reduced pigmentation (relative delta L 2.98, p value < 0.01). These findings suggest that cosmetic or pharmaceutical formulations incorporating AL extract or moranoline may potentially improve PIH caused by acne-related inflammation.

Acne vulgaris is a multifactorial inflammatory skin disorder driven by excessive sebum secretion, follicular obstruction, and Cutibacterium acnes (C. acnes) proliferation. Conventional topical treatments often suffer from insufficient drug penetration and challenges in co-delivery of drugs with contrasting physicochemical properties. In this study, a dual drug-loaded dissolving microneedle (MN) system was developed for the simultaneous transdermal delivery of the hydrophilic photosensitizer precursor 5-aminolevulinic acid (ALA) and the hydrophobic retinoid isotretinoin (IT). IT was encapsulated in Pluronic F127 micelles via thin-film hydration, and the resulting micelles were incorporated together with ALA into a hyaluronic acid matrix to fabricate dissolving MNs by mold casting. The fabricated MNs exhibited well-defined morphology and sufficient mechanical strength to penetrate the stratum corneum. Dynamic light scattering (DLS) analysis confirmed that the micellar structure was preserved during MN fabrication and dissolution, enabling IT to be released in micellar form with a relatively slower permeation profile, while ALA was rapidly released. In vitro studies demonstrated that ALA-PDT effectively eradicated C. acnes and inhibited lipid synthesis in sebocytes, while IT independently suppressed sebocyte lipogenesis. Notably, the combination of ALA-PDT and IT achieved enhanced inhibition of lipid synthesis compared to either treatment alone. Cytocompatibility assays confirmed the favorable biosafety of the MN system. This dual drug-loaded dissolving MN platform enables efficient co-delivery of hydrophilic and hydrophobic drugs and achieves complementary anti-acne effects through distinct mechanisms, offering a promising strategy for acne treatment.

In this work, a novel approach for the synthesis of zinc oxide (ZnO) fibers is presented that is based on centrifugal spinning from optimized spinning solutions, followed by tailored annealing. The resulting ZnO fibers were evaluated for their antibacterial properties and compared to commercial ZnO nanoparticles (NPs). Initially, precursor fibers were produced by centrifugal spinning using polyvinylpyrrolidone (PVP) and zinc nitrate solutions. The as-spun fibers were subsequently annealed at 500 °C to produce ZnO fibers with an average diameter of 1 µm. The fibers were then milled for 20 seconds at a constant frequency using a ball mill, yielding an average fiber length of 6.6 µm. Comprehensive characterization was performed using SEM, XRD, and BET analyses together with evaluation of antibacterial activity against Acne vulgaris (AV)-causing bacteria, Cutibacterium acnes, which was compared with ZnO NPs with an average diameter of 40 nm. The obtained results revealed antibacterial activity of as-synthesized ZnO fibers from a concentration of 1 wt% when dispersed in suspension. These findings underscore the potential of ZnO fibers for antibacterial applications, particularly in the treatment of AV.

Seborrheic dermatitis (SD) is a chronic inflammatory skin condition likely caused by several factors, including overgrowth of the lipophilic yeast Malassezia, increased sebaceous gland activity, and a potential genetic predisposition, whereas Malassezia folliculitis (MF) is a fungal infection of hair follicles. In this case, a 22-year-old male initially presented with erythematous papules on the malar region and was clinically diagnosed with SD. Following partial improvement with topical and oral antifungals, the patient developed new pustular lesions involving the malar and chin regions, raising suspicion of MF. The absence of comedones and cysts helped rule out Acne vulgaris. Potassium hydroxide mount from pustular swabs revealed numerous fungal spores, prompting further investigation. Culture on modified Leeming and Notman agar yielded yeast colonies, which appeared as budding yeast cells under light and fluorescence microscopy with Calcofluor white stain. Molecular identification using PCR for the ITS regions and RFLP analysis confirmed the isolate as Malassezia furfur. This case highlights the clinical progression from SD to MF, underscoring the pathogenic potential of Malassezia and the importance of integrating clinical, microscopic, and culture-based molecular diagnostic approaches for accurate diagnosis and targeted treatment in dermatological mycoses.

Severe juvenile acne vulgaris is a chronic inflammatory disorder that can impair quality of life and lead to permanent scarring during adolescence. Advances in understanding acne pathophysiology have shifted treatment toward early intervention, antimicrobial stewardship, and individualized systemic strategies.