ZINC OXIDE

Photoprotection has become integral in the prevention of keratinocyte cancer and photoaging. Organic ultraviolet (UV) filters such as oxybenzone and octinoxate have become controversial due to their potential impact on the environmental and their potential human health risks. As such, inorganic UV filters, zinc oxide (ZnO) and titanium dioxide (TiO 2 ) , have become paramount in discussions about photoprotection. ZnO and TiO 2 are used in sunscreens as nanoparticles, which denotes a size <100 nm. The smaller size of these mineral particles increases their cosmetic acceptability by users as they are much less visible after application. ZnO has a broad UVA-UVB absorption curve, while TiO 2 provides better UVB protection. Overall, the human health risks with inorganic filters are extremely low given a lack of percutaneous absorption; however, there is potential risk when exposed via inhalation, prompting recommendations against spray sunscreen products with nanoparticles. At this time, the known risk to the environment is low though the risk stratification may evolve with increasing usage of these filters and higher environmental concentrations. The continued practice of photoprotection is critical. The public should be counseled to seek shade, use photoprotective clothing including hats and glasses in addition to sunscreens on sun-exposed skin. For those concerned about emerging evidence of environmental impact of organic UV filters, based on current evidence, ZnO and TiO 2 -containing sunscreens are safe alternatives.

Zinc oxide (ZnO), an inorganic compound that appears as a white powder, is used frequently as an ingredient in sunscreens. The aim of this review was to examine the toxicology and risk assessment of ZnO based upon available published data. Recent studies on acute, sub-acute, and chronic toxicities of ZnO indicated that this compound is virtually non-toxic in animal models. However, it was reported that ZnO nanoparticles (NP) (particle size, 40 nm) induced significant changes in anemia-related hematologic parameters and mild to moderate pancreatitis in male and female Sprague-Dawley rats at 536.8 mg/kg/day in a 13-week oral toxicity study. ZnO displayed no carcinogenic potential, and skin penetration is low. No-observed-adverse-effect level (NOAEL) ZnO was determined to be 268.4 mg/kg/day in a 13-week oral toxicity study, and a maximum systemic exposure dose (SED) of ZnO was estimated to be 0.6 mg/kg/day based on topical application of sunscreen containing ZnO. Subsequently, the lowest margin of safety (MOS) was estimated to be 448.2, which indicates that the use of ZnO in sunscreen is safe. A risk assessment was undertaken considering other routes of exposure (inhalation or oral) and major product types (cream, lotion, spray, and propellant). Human data revealed that MOS values (7.37 for skin exposure from cream and lotion type; 8.64 for skin exposure of spray type; 12.87 for inhalation exposure of propellant type; 3.32 for oral exposure of sunscreen) are all within the safe range (MOS > 1). Risk assessment of ZnO indicates that this compound may be used safely in cosmetic products within the current regulatory limits of 25% in Korea.

Sunscreens containing metal oxide nanoparticles appear transparent on the skin and provide excellent protection against sunburn caused by UV radiation. While it is likely that nanoparticles remain on the surface of the skin of healthy adult humans, and thus are considered safe for use in sunscreens, there has been no comprehensive assessment of the impact on human health from exposure to the metal oxide nanoparticles destined for use in sunscreens, either in the workplace during the manufacturing process, in long-term use across a range of skin conditions, or upon release into the broader environment, either accidentally or consequent of normal sunscreen use. In this review, we focus on zinc oxide nanoparticles destined for use in modern sunscreens, and discuss the potential for human exposure and the health hazard at each stage of their manufacture and use. We highlight where there is a need for further research.

The UVA performances of two all-mineral zinc oxide sunscreens are measured following Colipa and ISO procedures and compared to a sunscreen containing only organic actives. It is found that the two sunscreen types yield very different in vitro SPF and UVA results. It shown that the results can be rationalized in terms of the differences in the monochromatic extinction spectra of the two types of sunscreens.

Sunscreens are used to provide protection against adverse effects of ultraviolet (UV)B (290-320 nm) and UVA (320-400 nm) radiation. According to the United States Food and Drug Administration, the protection factor against UVA should be at least one-third of the overall sun protection factor. Titanium dioxide (TiO2) and zinc oxide (ZnO) minerals are frequently employed in sunscreens as inorganic physical sun blockers. As TiO2 is more effective in UVB and ZnO in the UVA range, the combination of these particles assures a broad-band UV protection. However, to solve the cosmetic drawback of these opaque sunscreens, microsized TiO2 and ZnO have been increasingly replaced by TiO2 and ZnO nanoparticles (NPs) (<100 nm). This review focuses on significant effects on the UV attenuation of sunscreens when microsized TiO2 and ZnO particles are replaced by NPs and evaluates physicochemical aspects that affect effectiveness and safety of NP sunscreens. With the use of TiO2 and ZnO NPs, the undesired opaqueness disappears but the required balance between UVA and UVB protection can be altered. Utilization of mixtures of micro- and nanosized ZnO dispersions and nanosized TiO2 particles may improve this situation. Skin exposure to NP-containing sunscreens leads to incorporation of TiO2 and ZnO NPs in the stratum corneum, which can alter specific NP attenuation properties due to particle-particle, particle-skin, and skin-particle-light physicochemical interactions. Both sunscreen NPs induce (photo)cyto- and genotoxicity and have been sporadically observed in viable skin layers especially in case of long-term exposures and ZnO. Photocatalytic effects, the highest for anatase TiO2, cannot be completely prevented by coating of the particles, but silica-based coatings are most effective. Caution should still be exercised when new sunscreens are developed and research that includes sunscreen NP stabilization, chronic exposures, and reduction of NPs' free-radical production should receive full attention.

The global food security is threatened by the accumulation of anthropogenic nanomaterials in the environment. We investigated the phytotoxic effects of elevated zinc oxide nanoparticles ([ZnO]NPs: 300-400 mg L⁻ 1 ) on wheat (Triticum aestivum L.) and evaluated a novel detoxification strategy using successive redox-priming. Wheat caryopses were primed with alpha-lipoic acid (LA) and sodium nitroprusside (SNP, a nitric oxide donor) either individually or in successive sequences (LA→SNP and SNP→LA). Exposure to [ZnO]NPs resulted in significant growth inhibition, reduction of biomass and degradation of chlorophyll. However, successive priming, particularly the LA+SNP combination, significantly attenuated these negative effects. This treatment effectively restored seedling growth by creating a strong antioxidant shield, greatly increasing the activities of SOD, POD, CAT, and APX, and raising metal chelating activity to 98.1%. Furthermore, Density Functional Theory (DFT) calculations, including HOMO-LUMO and molecular electrostatic potential (MEP) analyses, gave mechanistic insights into the molecular interactions of the priming agents and ZnO, highlighting their role as potent radical scavengers and stabilizers. The results indicate that a successive redox priming is an effective and sustainable approach to enhance crop tolerance to high concentrations of nanoparticle toxicity.

Visible light (VL, 400-700 nm) and long wavelength UVA1 (VL + UVA1, 370-700 nm) have been reported to cause erythema in light skin phototypes, Fitzpatrick skin types I-III (FST I-III), and to exacerbate pigmentary dermatologic conditions (e.g., melasma, hyperpigmentation, post-inflammatory hyperpigmentation) in individuals with dark skin phototypes (FST IV-VI). Until recently, limited options existed for photoprotection against VL + UVA1, including tinted formulations containing iron oxides (Fe 2 O 3 ) or pigmentary titanium dioxide (TiO 2 ), as well as antioxidant-enriched sunscreen systems. Zinc oxide (ZnO) and TiO 2 are often utilized in the development of mineral-based (inorganic) sunscreens as the active ingredients to protect against broad spectrum Ultraviolet (UV) radiation via their absorption properties. However, some of these products often leave a white cast, particularly on dark skin, making these products unfavorable, altering skin tone appearance leading to concerns for sunscreen compliance. Tinted sunscreens (Fe 2 O 3 ) are designed to enhance cosmetic elegance and improve compliance across diverse skin tones. This study aims to evaluate the photoprotection properties of a novel Zn-based inorganic tinted sunscreen enriched with five antioxidants (5 AOX) against VL + UVA1 induced biologic effects (hyperpigmentation and erythema). Twelve healthy adult subjects with FST IV-VI were enrolled and the effectiveness of the new Zn/Fe 2 O 3 /5 AOX sunscreen, compared to several commercially available tinted and non-tinted mineral sunscreens, was evaluated. The erythema and pigmentation assessments were performed by diffused reflectance spectroscopy (DRS), polarized photography, and investigator global scoring immediately, 24 h, and 7 days after irradiation (320 J/cm 2 ). DRS results demonstrated that the novel Zn/Fe 2 O 3 /5 AOX effectively reduced immediate erythema and pigmentation as well as delayed pigmentation when compared with formulas containing ZnO only (p < 0.05). Not all inorganic/Fe 2 O 3 formulas significantly reduced erythema and pigmentation induced by VL + UVA1 when compared with the ZnO only formula. These results highlight the enhanced effects of 5 AOX-enriched tinted mineral sunscreen to be photoprotective against VL + UVA1, with a blendable tint designed for use on skin of all colors aimed at improving patient compliance and overall sunscreen use.

The rise of antimicrobial resistance (AMR) has created an urgent need for alternative therapies, particularly against biofilm-driven polymicrobial wound infections. Although green-synthesized nanoparticles have emerged as promising candidates, many studies lack rigorous validation of their quantum properties, fail to clarify mechanisms of action, and omit essential cytotoxicity profiling in human cells. To synthesize silver (Ag), copper (Cu), and zinc oxide (ZnO) quantum dots (QDs) using Quercus brantii acorn extract, confirm quantum confinement effects, and evaluate their antimicrobial efficacy, mechanistic basis, and biosafety in a clinically relevant murine wound model. QDs were synthesized via a standardized hydrothermal approach. Quantum confinement was verified using photoluminescence (PL) spectroscopy and Tauc plot analysis. Antimicrobial activity was tested against multidrug-resistant (MDR) clinical isolates of Pseudomonasaeruginosa, methicillin-resistant Staphylococcus aureus (MRSA), Acinetobacter baumannii, and Klebsiella pneumoniae. To differentiate oxidative stress from chemical artifacts, we employed non-thiol reactive oxygen species (ROS) scavengers (Trolox, Mannitol) and electron paramagnetic resonance (EPR). Cytotoxicity was assessed in human keratinocytes (HaCaT) and dermal fibroblasts (HDF). In vivo efficacy was evaluated in a murine excisional wound model infected with a polymicrobial consortium, tracking pathogen-specific clearance. Hydrogel rheology and stability were also characterized. Monodispersed, crystalline QDs with evidence consistent with quantum confinement were obtained (Ag-QDs: 7.2 ± 1.5 nm; apparent bandgap: 2.85 eV). Ag-QDs showed strong antimicrobial activity (MIC: 4.5-18.1 µg/mL) and biofilm inhibition (up to 85% at ½×MIC). Mechanistic experiments, including EPR and ROS-scavenger assays, supported ROS-associated oxidative stress as a major contributor to bacterial killing under the tested conditions. Ag-QDs exhibited bactericidal activity at concentrations that were non-toxic to human skin cells in the employed assay (Selectivity Index for MRSA: 18.9). In vivo, topical application of an Ag-QD hydrogel (shear-thinning) accelerated wound closure to 95.3% by Day 14 (comparable to uninfected controls) and reduced the total bacterial burden by 4.2 log₁₀ CFU/g; all four pathogens were below the detection limit at the study endpoint. No overt systemic toxicity was observed based on the assessed biomarkers. Resistance development in serial passage assays was limited (2-fold MIC increase after 30 passages), noting that longer-term polymicrobial studies are required to fully evaluate resistance evolution. Q. brantii-mediated Ag-QDs are a promising green-synthesized nanomaterial with physicochemical characteristics consistent with quantum-dot behavior and notable antimicrobial and antibiofilm activity against MDR polymicrobial communities. In a preclinical murine wound model, topical Ag-QD hydrogel treatment was associated with accelerated wound closure and marked reductions in bacterial burden, alongside a favorable preliminary biosafety profile based on the endpoints assessed. Further studies are warranted to validate efficacy in clinically relevant chronic wound settings (e.g., diabetic models), to expand long-term toxicology, and to clarify resistance evolution and mechanistic pathways in polymicrobial systems.

Animal glue stains are commonly found in manuscripts, and their removal is a delicate process that requires selective treatment to avoid damaging the fragile cellulose fibers. Therefore, this study developed a novel hybrid double network hydrogel (HDNH) consisting of synthetic polymer (Polyacrylamide), natural polymers (Agarose or sodium alginate), and Zinc Oxide nanoparticles (ZnONPs) for removing animal glue stains from paper manuscripts. The cleaning mechanism relies on the capillary HDNH to draw the aged animal glue into the gel matrix. To establish the suitability of this HDNH as a paper-cleaning material, the gels were first characterized physicochemically and microstructurally, and the HDNH formulation was confirmed. At the same time, mechanical, physicochemical, morphological, optical, and wettability techniques were performed on the paper samples under investigation, both before and after the cleaning treatment, to evaluate the HDNHs' cleaning capabilities. The results show that the Polyacrylamide/Agarose/ZnONPs (HDNH/Ag/ZnONPs) provide superior performance in removing most of the accumulated glue layers while maintaining the structural and chemical integrity of the paper substrate. Agarose provides a very rigid, highly porous structure with a superior capacity to retain water, preventing the paper from becoming waterlogged. Polyacrylamide provides flexibility and mechanical durability, allowing the hydrogel to be peeled off in one piece.

Diabetes mellitus is a global concern with complications including recurrent skin infections and poor wound healing. The involvement of multidrug-resistant bacteria (MDR) in skin infections renders them challenging. Nanoparticles such as silver, zinc oxide, and chitosan-based nanoparticles offer a promise for combating the growing threat of MDR bacteria by employing unique mechanisms that bypass recognized antibiotic resistance pathways. Therefore, this study reports the eco-friendly synthesis of silver (AgNPs), zinc oxide (ZnONPs), and chitosan-tripolyphosphate nanoparticles (Cs-TPP-NPs) using green tea extract (GTE) and gamma irradiation. AgNPs exhibited the highest antibacterial and antibiofilm efficacy among the tested preparations, as reflected by their lowest minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values against four bacterial strains associated with diabetic foot ulcers, including Pseudomonas aeruginosa, Escherichia coli, methicillin-resistant Staphylococcus aureus (MRSA), and Streptococcus pyogenes. The killing activity of AgNPs was fast acting against all tested bacteria with > 10 log 10 CFU/mL reduction in 2-6 h. The AgNPs-GTE loaded Cs-TPP-NPs combination was assessed for possible mechanisms of action, which revealed its ability to inhibit biofilm formation and compromise bacterial membrane integrity in MRSA and E. coli, leading to increased permeability, intracellular ion leakage, and nucleic acid release. Notable morphological damage to bacterial cells was confirmed by transmission electron microscope (TEM).  In vivo, the prepared combination hydrogel promoted healing of skin lesions in a CD1  mouse model of diabetic skin infection lesion within six days, demonstrating strong antibacterial activity with a 4 Log 10 unit reduction in bacterial load compared with the untreated group, and significant decrease in inflammatory marker NF-kB, restoring it to healthy uninfected control levels. Histopathological evaluation of treated tissues showed full epidermal regeneration, enhanced fibroblast proliferation, increased angiogenesis, and the presence of well-organized mature collagen fibers in the dermis, compared to untreated controls. In conclusion, synthesized AgNPs-GTE loaded Cs-TPP-NPs combination offered an effective therapeutic approach for enhancing diabetic skin infection healing.

Zinc oxide nanoparticles (N-ZnO) represent a promising alternative for zinc (Zn) supplementation, since their reduced size provides greater bioavailability and better integration into the body. Furthermore, this characteristic becomes particularly relevant during periods of increased metabolic stress, such as the transition phase. Thus, the objective was to evaluate the effects of N-ZnO supplementation in Santa Inês sheep during the peripartum period. Thirty-three ewes with an average body weight of 43.3 ± 2.05 kg were, distributed into three experimental groups: control group (CON), without supplementation, receiving only Cynodon spp. hay; and groups supplemented with 300 mg/animal/day of N-ZnO (40 nm) and zinc oxide microparticles (M-ZnO). The supplementation was administered orally in capsules daily from late pregnancy until weaning. The results showed no significant differences (P > 0.05) in body weight, egg count per gram of feces (EPG), and in most of the hematological, biochemical, and immunological parameters evaluated. However, differences (P < 0.05) were observed in monocyte counts and albumin levels, with higher means in the N-ZnO group, showing differences compared with the M-ZnO group, while the CON group maintained intermediate values. The N-ZnO group showed differences compared to the M-ZnO group, while the CON group maintained intermediate values. Regarding antioxidant activity, a significant effect (P < 0.05) was observed on the enzymes Superoxidase dismutase (SOD), Glutathione peroxidase (GPx), Catalase (Cat), and on the total antioxidant status (ORAC) of the sheep supplemented with N-ZnO. It is concluded that N-ZnO supplementation improved the antioxidant response, with no signs of intoxication, using a dose of 300 mg during the period of greatest oxidative stress.

Bacterial biofilms are a major cause of persistent and device-related infections due to their antibiotic resistance and ability to shelter bacteria. Zinc oxide nanocrystals (ZnO NCs), with their multiple antimicrobial mechanisms, have emerged as efficient antibacterial agents. In this study, we synthesized rod-shaped ZnO NCs and evaluated their anti-biofilm efficacy against Escherichia coli . Anti-biofilm activity was assessed at sub-minimum inhibitory concentration (MIC) and MIC levels. Transcriptomic analysis and qPCR were employed to examine gene expression changes in E. coli , with further mechanistic validation targeting specific metabolic pathways. At sub-MIC levels, ZnO NCs potently inhibited biofilm formation and eradicated pre-formed E. coli biofilms. These treatments also markedly suppressed the synthesis of key extracellular polymeric substances (EPS) components, while MIC-level treatments effectively degraded existing EPS in mature biofilms. Concurrently, ZnO NCs reduced overall EPS density, loosened biofilm architecture, and increased its structural heterogeneity. Furthermore, bacterial motility (swimming, twitching, and swarming) was strongly impaired across sub-MIC to MIC concentrations. Transcriptomic analysis revealed that ZnO NCs downregulated genes associated with biofilm formation, motility, and amino acid biosynthesis. qPCR indicated that the downregulation of glgA and gltB impaired the synthesis of key EPS components. Mechanistically, we validate that in E. coli , ZnO NCs suppress glgA to disrupt glycogen-derived carbon precursors for polysaccharide synthesis, and downregulate gltB to impair glutamate synthase activity, thereby limiting nitrogen assimilation and amino acid supply for proteinaceous EPS components. These findings elucidate a previously undefined mechanism wherein ZnO NCs dismantle E. coli biofilms by simultaneously targeting two pivotal metabolic nodes ( glgA and gltB ) that fuel EPS production. This work provides not only a deeper mechanistic insight into anti-biofilm action against E. coli but also supports the potential of ZnO NCs as multi-targeted anti-biofilm agents.

This work examines the BaO, ZnO and CaO metal oxides' role in lead borate glasses' mechanical, optical and radiation shielding performance. Using the melting-quenching method at 1100°C, the lead borate glass system was fabricated. According to the Makishima-Makinze model, the most elevated mechanical properties were for the glass samples with CaO additives, including elastic moduli, hardness and bond strength. On the other hand, the glass samples with BaO additives achieved the lowest mechanical properties, while the ZnO compound glasses had intermediate glass former and modifier properties. Furthermore, the fabricated glasses' optical property measurements confirmed that the glass samples with ZnO additives had the lowest refractive index, 2.306, while the CaO-containing glasses had a refractive index of 2.617. The impact of various metal oxides (BaO, CaO and ZnO) on the fabricated glasses' shielding performance was examined using the Monte Carlo simulation code along the energy interval of 0.02-10 MeV. The glass samples with BaO additives have the highest LACs among the investigated glasses, which decreased from 132.135 to 0.140 cm -1 when the γ-ray energy rose between 0.02 and 10 MeV.

Infections are the most frequent complication that impair normal skin repair, often leading to chronic wounds. To overcome this challenge, zinc oxide nanoparticles (ZnO NPs) were synthesized via green combustion using Moringa oleifera extract as fuel. These nanoparticles were incorporated into a poly(caprolactone)/poly(ethylene oxide) (PCL/PEO) membrane fabricated via electrospinning. The composite membranes were characterized by water contact angle, fluid absorption, morphology (SEM), cytotoxicity, cell proliferation (scratch assay), and antibacterial activity against Staphylococcus aureus and Escherichia coli . The PCL/PEO membrane containing 5% ZnO exhibited optimal characteristics, including hydrophilicity, water uptake capacity exceeding 300%, and a morphology that is suitable for wound healing applications, with an average fiber diameter of 2.93 ± 2.05 µm, pore size of 21.46 ± 8.19 µm, and porosity exceeding 75%. Additionally, the membrane demonstrated excellent biocompatibility with murine fibroblasts, achieving a cell viability of 100%, and exhibited antibacterial activity against Staphylococcus aureus and Escherichia coli , with inhibition zones of 2.0 and 1.0 mm, respectively. The green synthesized moringa-ZnO imparted outstanding properties to the electrospun membrane, making the system PCL/PEO/moringa-ZnO a promising candidate for advanced wound dressings capable of promoting accelerated wound closure and treating infected wounds.

The rising prevalence of multidrug-resistant (MDR) pathogens necessitates the development of sustainable, biocompatible antimicrobial agents. Green synthesis of metal oxide nanoparticles using endophytic microorganisms offers an eco-friendly and bioactive alternative to conventional physical and chemical methods. In this study, zinc oxide nanoparticles (ZnO NPs) were biosynthesized using the cell-free supernatant of Streptomyces werraensis, a novel endophytic actinobacterium isolated from the medicinal plant Passiflora caerulea L. The formation of ZnO NPs was monitored via UV-visible spectroscopy and Fourier Transform Infrared (FTIR) spectroscopy. Morphological and structural characterizations were performed using Transmission Electron Microscopy (TEM), Selected Area Electron Diffraction (SAED), and Dynamic Light Scattering (DLS). The biological potential of ZnO NPs for human health was evaluated through antibacterial assays against a panel of human pathogens and antioxidant assays (DPPH and ABTS). UV-Vis spectra confirmed ZnONP formation with a characteristic band-gap absorption, while FTIR identified proteinaceous and phenolic capping agents. TEM and SAED revealed highly crystalline, predominantly spherical nanoparticles with an average diameter of 136 nm and a wurtzite crystal structure. The biosynthesized ZnO NPs exhibited potent, concentration-dependent antibacterial activity, particularly against Gram-negative strains; Salmonella paratyphi A and Proteus vulgaris showed maximum inhibition zones of 19.0 ± 0.64 mm and 16.4 ± 0.68 mm, respectively, which are comparable to those of commercial ampicillin. Antioxidant assays demonstrated significant radical-scavenging potential, with an IC50 of 22.15 ± 1.2 µg/mL in the ABTS assay, approaching that of ascorbic acid. The findings of the present study demonstrate that S. werraensis-mediated ZnO NPs serve as effective "nanogenerators" of oxidative stress, offering a dual-action therapeutic approach. These results highlight the potential of endophytic actinobacteria as sustainable bio-factories for producing functional nanoparticles with promising antimicrobial potential for treating MDR infections.

D-galactose promotes insulin resistance (IR) and neurodegeneration through hyperglycemia, advanced glycation end products (AGEs), oxidative stress, amyloid-β accumulation, and disruption of the insulin signalling pathway, leading to neuroinflammation and neuroapoptosis. The purpose of this study was to investigate the insulin signalling pathway and efficacy of ZnO nanoparticles (ZnO NPs) in alleviating brain IR and neurodegeneration via regulating IRS/PI3K/AGER/APP signalling. In this study, bioinformatic analysis of hub genes and PIP network revealed the interconnection between PI3K/Akt signalling pathway and neuroinflammation pathway leading to neurodegeneration. Further, in vivo analysis on 4-month-old C57BL/6 mice was randomised into control (NC), 50 mg/kg of D-galactose (DC), D-galactose + 450 μg/Kg of ZnO NPs (Z1), D-galactose + 650 μg/Kg of ZnO NPs (Z2), and D-galactose + 20 mg/kg of metformin (MF). Blood glucose, Amadori products, conjugated dienes, amyloid-β deposition, and gene and protein expression of the IRS/PI3K/AGER/APP signalling pathway were analysed. Our findings illustrated that ZnO NPs (Z1) alleviated hyperglycemia, cleared amyloid-β accumulation, maintained neural integrity, lessened fat deposition in the liver, and altered the expression of irs2 , pi3k , ager , and app genes. Thus, ZnO NPs offer a therapeutic strategy for managing IR and neurodegeneration.

Management of chronic prurigo (CPG), including prurigo nodularis (PN), is challenging due to its chronic, often treatment-refractory course, high disease burden, and increasing complexity of therapies. International guidelines are partly outdated and may not fully reflect country-specific considerations. Our aim was to develop practice recommendations for the diagnosis and treatment of CPG. Twelve hospital- and practice-based experts formulated recommendations following a standardized literature review and structured expert consensus process, with recommendations voted on until ≥ 75% agreement was reached. Recommendation levels were guided by the GRADE methodology but adapted to allow practical, differentiated guidance, including the additional "Can be considered" category. Recommendations address history taking, laboratory testing, biopsy, questionnaires, general measures, pharmacological and non-pharmacological therapies. "We recommend" applies to topical corticosteroids, narrow-band ultraviolet B (NB-UVB), dupilumab, and nemolizumab; "We suggest" to topical calcineurin inhibitors, zinc oxide dressings, cryotherapy, intralesional corticosteroids, gabapentinoids, antidepressants, methotrexate, ciclosporin, μ-opioid receptor antagonists, Janus kinase inhibitors, and cognitive behavioral techniques; and "Can be considered" to capsaicin, ultraviolet A1 (UVA1), psoralen plus ultraviolet A (PUVA), and sedating antihistamines for sleep. No recommendation could be made for azathioprine, non-sedating antihistamines, κ-opioid receptor agonists, retinoids, neurokinin-1 receptor antagonists, thalidomide, or lenalidomide. These recommendations provide comprehensive, up-to-date guidance for CPG, supporting clinicians in Switzerland and internationally.