Acute paronychia in children is typically associated with trauma or habitual behaviors, whereas cosmetic-related cases are rarely reported. We describe a 4-year-old girl who developed acute paronychia with persistent green nail-bed pigmentation following the application of nail polish to a nail with pre-existing cuticular disruption. Staphylococcus epidermidis was isolated from purulent discharge, while Pseudomonas aeruginosa was not detected. The clinical course supports a dual pathogenic mechanism involving bacterial invasion through a compromised cuticle and chemical irritation from cosmetic components. The observed green discoloration, confined to the nail bed and occurring in the absence of P. aeruginosa, represents an atypical presentation distinct from classical chloronychia. This case highlights that cosmetic products may represent an underrecognized trigger of nail infections in children, particularly when applied to compromised nail units, and underscores the need for clinician awareness as the use of children's cosmetic products continues to expand.

Paronychia represents an underexplored clinical condition with limited alternatives to conventional antimicrobial therapies, which are increasingly compromised by antibiotic resistance and toxicity. Here, we report for the first time the extracellular biosynthesis of silver nanoparticles (BAgNPs) using Bacillus stercoris 2AT10, a marine-derived bacterium not previously exploited for nanoparticle production. By integrating green nanotechnology with genome mining approaches, we investigated the molecular basis underlying nanoparticle formation and evaluated the potential of BAgNPs against pathogens associated with paronychia. Physicochemical characterization by ultraviolet-visible (UV-Vis) spectroscopy confirmed the presence of particles, with mean sizes ranging from 47 to 87 nm measured by dynamic light scattering (DLS). Their spherical shape was confirmed by transmission electron microscopy (TEM), whereas Fourier-transform infrared (FTIR) spectroscopy suggested the presence of hydroxyl, amide, and nitrogen-containing groups possibly associated with reducing or capping action. Genes encoding nitrate reductases, laccases, and bioactive secondary metabolites, such as bacillibactin, subtilosin A, bacillaene, bacilysin and fengycin, that may be involved in silver ion reduction and nanoparticle stabilization were identified by genome annotation using eggNOG-mapper and antiSMASH. The biosynthesized AgNPs exhibited potent broad-spectrum antimicrobial activity against paronychia-associated pathogens, notably with inhibition zones of 25.8 mm for Staphylococcus aureus and of 23.2 mm for Pseudomonas aeruginosa. The Hen's Egg Test on the Chorioallantoic Membrane (HET-CAM) assay showed the nonirritating profile of the biosynthesized particles (irritation index ≤ 1), supporting further investigation of their suitability for topical applications, pending additional biocompatibility studies. Collectively, these findings establish B. stercoris-derived BAgNPs as a promising green nanotechnology platform to address the unmet need for safe and effective prophylactic agents against bacteria associated with paronychia, with additional potential as antimicrobial preservatives for dermocosmetic formulations.

Skin toxicities like paronychia and acneiform rash are common side effects of epidermal growth factor receptor tyrosine kinase inhibitors (EGFR TKI) and significantly impact patients' quality of life. Tetracycline antibiotics are the recommended first-line treatment but can cause side effects, leading to intolerance and untreated toxicities, highlighting needs for alternative therapies. We present a case of stage IV EGFR-mutated non-small cell lung cancer (NSCLC) treated with the second-generation EGFR TKI, dacomitinib. The patient developed grade 3 skin toxicities and was subsequently treated with azithromycin after demonstrating intolerance to tetracycline antibiotics. Azithromycin was administered using various dosing strategies, and we found 500 mg every other day might be the most effective regimen for treating EGFR-TKI-induced acneiform rash. However, this approach appeared to be less effective in managing paronychia.

Paronychia is a frequent cutaneous adverse event associated with MEK inhibitor therapy and may significantly impair quality of life and compromise treatment adherence. Treatment is usually medical, with poor and unsustained results. We retrospectively evaluated the safety and efficacy of CO2 laser matrixectomy in children at a tertiary center between 2016 and 2026. Five patients with prolonged symptoms despite multiple conservative treatments were identified. Complete resolution was achieved in all patients, with no procedure-related complications. MEK inhibitor therapy was continued without recurrence of paronychia. Outcomes remained favorable during a mean follow-up of 4 years.

Infections of the hand are encountered across emergency medicine, primary care, and surgical practice, and their outcomes depend heavily on early recognition. The complex anatomy of the hand, with its multiple fascial planes, tendon sheaths, and confined spaces, allows infection to spread rapidly and produce lasting functional impairment when treatment is delayed. This pictorial review presents a series of clinically important hand infections drawn from the archive of a board-certified hand surgeon, spanning common superficial conditions to uncommon but limb-threatening deep-space, articular, and osseous disease. For each entity, we summarize characteristic clinical features, useful diagnostic and imaging findings, likely causative organisms, and initial management, illustrated with representative clinical photographs and imaging. By organizing these conditions across tissue planes, the review offers a practical, pattern-based reference that clinicians can use at the point of care to triage urgency, select empiric therapy, and identify patients who require early referral or operative intervention.

Lazertinib is a third-generation, brain-penetrant, mutant-selective EGFR tyrosine kinase inhibitor approved for first-line treatment of EGFR-mutated non-small cell lung cancer, including in combination with amivantamab. Post-market safety surveillance is important given its recent approval and evolving real-world use. All FAERS reports with lazertinib as the primary suspect drug were extracted. Proportional Reporting Ratios (PRR), Reporting Odds Ratios (ROR), and chi-squared statistics were calculated for each adverse event. Disproportionality signals were defined by PRR ≥ 2, chi-squared ≥ 3.841, and a minimum of 3 reports. A total of 141 lazertinib reports were identified in the FAERS database. Twenty-six adverse events met all signal detection criteria. The strongest signals were observed for paronychia (PRR 132.90, n = 3), dermatitis acneiform (PRR 118.59, n = 4), peripheral sensory neuropathy (PRR 91.97, n = 3), and peripheral neuropathy (PRR 50.09, n = 28). Dermatologic and neurologic adverse events predominated, consistent with the mechanism of EGFR inhibition. FAERS disproportionality analysis identifies a signal profile for lazertinib dominated by EGFR inhibitor-class dermatologic and neurologic toxicities, alongside an infusion-related reaction signal reflecting combination use with amivantamab. The modest report volume warrants cautious interpretation; however, the signal patterns are mechanistically coherent and consistent with the known toxicity profile of third-generation EGFR TKIs.

Onychophagia, commonly referred to as nail biting, is a body-focused repetitive behavior that occurs most frequently in children and adolescents. Although often perceived as a harmless habit, repetitive trauma to the periungual tissues can compromise the integrity of the cutaneous barrier and increase susceptibility to secondary bacterial infection. Extension of infection into deep soft tissues with associated bone involvement is uncommon, particularly within the pediatric population. We present the case of a 10-year-old female patient who arrived at the emergency department with progressive infection of the left third digit in the setting of chronic nail biting. The condition initially began as a hangnail that developed into paronychia and subsequently progressed to a felon despite outpatient treatment that included oral and topical antimicrobial therapy and incision and drainage. At the time of emergency evaluation, a substantial distal soft tissue defect with persistent drainage was observed. Plain radiographs demonstrated soft tissue disruption without clear evidence of early bony destruction. Subsequent magnetic resonance imaging identified a small distal fluid collection consistent with abscess formation and signal abnormalities of the distal phalanx suggestive of osteomyelitis. Given concern for deep infection, a hand surgery consultation was obtained, and the patient was transferred to a tertiary pediatric center. She was ultimately treated non-operatively with culture-directed antimicrobial therapy and close multidisciplinary follow-up, resulting in marked clinical improvement. This case demonstrates a rare but significant complication of chronic nail biting in a pediatric patient and reinforces the need for careful assessment of worsening digital infections. Clinicians should consider advanced imaging and early specialty involvement when periungual infections do not respond to initial outpatient management, as prompt recognition and intervention are essential to minimize long-term morbidity and preserve function.