[A study on the hearing protection and intervention effects of silicone earplug usage among manufacturing workers].

Objective: To assess the efficacy of silicone earplugs in protecting workers exposed to noise in a typical manufacturing environment, and to provide training interventions for workers who do not achieve the anticipated noise reduction levels, as well as examining the spectral characteristics of earplug attenuation. Methods: From June to August 2022, a total of 294 noise-exposed workers in two manufacturing enterprises equipped with the same type of earplug were studied by cluster sampling method, by conducting questionnaire surveys, collecting data, fitting tests, and providing trainings, the current noise exposure levels of workers in the industry as well as the perception about the earplug were understood. Additionally, the attenuation before and after intervention in workplace were measured, the spectral characteristics of noise reduction were were described and compared. Results: The percentage of workers with Personal Attenuation Rating (PAR) of 0 is 32.7% (96/294), and the baseline pass rates are all below 60%. There were no significant differences in pass rates based on gender, age, noise exposure, education level, or cognition of earplug effectiveness. After adjusting the way that earplugs are worn or changing the type of earplugs, all workers were able to meet their noise reduction requirements. The median PAR improvement for both companies is above 10 dB. The noise attenuation of the earplug vary with frequency, with lower attenuation at 4 000 Hz and higher attenuation at 8 000 Hz, showing some deviation from the nominal values. Conclusion: The difference between the actual sound attenuation value of earplugs and the nominal value is related to the noise frequency. When using silicone earplugs, attention should be paid to the spectral composition of the noise in the workplace.

In vitro effects of N-acetylcysteine in combination with antifungal agents against Malassezia pachydermatis isolated from canine otitis externa.

BACKGROUND: Many clinicians prescribe antifungal agents to treat canine otitis externa (OE). However, studies evaluating the antifungal effects of N-acetylcysteine (NAC) and its combinations are limited. HYPOTHESIS/OBJECTIVES: The aim of this study was to evaluate the antifungal effects of NAC alone and in combination with other antifungal agents against Malassezia pachydermatis isolated from canine OE. MATERIALS AND METHODS: M. pachydermatis samples were collected from 13 dogs with OE. The final concentration of the inoculum suspensions of M. pachydermatis was 1-5 × 106 colony forming units/mL. The concentrations of the test compounds ketoconazole (KTZ), terbinafine (TER), nystatin (NYS) and NAC were 0.02-300 µg/mL, 0.04-80 µg/mL, 0.16-40 µg/mL and 1.25-20 mg/mL, respectively. The minimum inhibitory concentration (MIC) was measured to evaluate the susceptibility of the M. pachydermatis to KTZ, TER, NYS and NAC. The checkerboard testing method and fractional inhibitory concentration index were used to evaluate the effect of NAC in combination with KTZ, TER and NYS against M. pachydermatis. RESULTS: The MIC90 values of M. pachydermatis were 4.6875-9.375 µg/mL, 1.25 µg/mL, 5-10 µg/mL and 10 mg/mL for KTZ, TER, NYS and NAC, respectively. The synergistic effects of KTZ, TER and NYS with NAC were identified in 0/13, 2/13 and 0/13 isolates, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: NAC had an antifungal effect against M. pachydermatis but did not exert synergistic effects when used with KTZ, TER and NYS. Thus, the use of NAC alone as a topical solution could be considered an effective treatment option for canine OE involving M. pachydermatis.

Melanoma of the external auditory canal: case report and systematic literature review.

Melanoma of the external auditory canal (EAC) is particularly rare and poorly understood, with limited available data on management and survival. This systematic review aims to analyze existing data and provide insights into the management and prognosis the beginning of EAC melanoma. It is conducted using Pubmed and Scopus databases from the beginning to July 2023 and it follows the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) 2020 guidelines. Searches are performed using the search string "(melanoma) AND (external auditory canal)".The review includes a total of 30 patients diagnosed with EAC melanoma, supplemented by an additional case from the authors' clinical experience. The role of Breslow thickness as a determining factor for the choice of surgery remains inconclusive due to limited available data. Sentinel lymph node biopsy and adjuvant therapy are sparingly employed, indicating the need for standardized guidelines. Patients in the study demonstrate a 50% overall survival rate at 5 years.EAC Melanoma is a rare and aggressive malignancy with limited therapeutic guidelines. Surgical interventions, including wide local excision and lateral temporal bone resection, are the primary treatment options for patients without distant metastases.

Otology: Cerumen Impaction and Aural Foreign Bodies.

Cerumen lubricates and protects the external auditory canal, but excess accumulation can lead to ear fullness, itching, otalgia, discharge, hearing loss, and tinnitus. Cerumen should be treated whenever symptoms are present or if it limits diagnosis by preventing a needed otoscopic examination. Clinicians should evaluate for cerumen impaction in those using hearing aids and patients with intellectual disability. Cerumen impaction can be treated with cerumenolytics, ear irrigation, and manual removal with instrumentation. Aural foreign bodies can cause ear fullness, otalgia, discharge, and hearing loss. They are more common in children than adults. The most common type of aural foreign bodies in children is jewelry, followed by paper products, parts of pens or pencils, desk supplies (eg, erasers), BBs or pellets, and earplugs or earphones. In adults, the most common aural foreign bodies are cotton swabs or cotton, followed by hearing aid parts and jewelry or ear accessories. Patients should avoid using cotton tip applicators in the external auditory canal. Alligator forceps, small right angle hooks, and ear irrigation commonly are used to remove aural foreign bodies in an outpatient clinic setting, but the choice depends on the type of foreign body. Soft and irregularly shaped objects can be removed without referral to an otolaryngologist. Patients with hard, spherical, or cylindrical objects should be referred to an otolaryngologist if previous removal attempts have failed or if there is ear trauma to avoid worsening its position in the ear canal.

Otology: Ear Infections.

Acute otitis media (AOM) is a common diagnosis in children who present with symptoms of otalgia, fever, or irritability and is confirmed by a bulging tympanic membrane or otorrhea on physical examination. It often is preceded by a viral infection, but the bacterial pathogens isolated most commonly are Streptococcus pneumonia, Haemophilus influenzae, and Moraxella catarrhalis. Watchful waiting may be appropriate in children 6 months or older with uncomplicated unilateral AOM. When antibiotics are indicated, amoxicillin is the first-line treatment in those without recent treatment with or allergy to this drug. Otitis media with effusion (OME) is fluid in the middle ear without symptoms of AOM and typically resolves within 3 months. Tympanostomy tube placement is the most common ambulatory surgery for children in the United States. It is used to ventilate the middle ear space and may be performed to treat recurrent AOM, persistent AOM, or chronic OME. Acute otitis externa is inflammation of the external ear canal, often due to infection. On examination, the ear canal is red and inflamed, with patients typically experiencing discomfort with manipulation of the affected ear. It is treated with a topical antibiotic with or without topical corticosteroid.

Histiocitosis de células de Langerhans en un paciente con lesión perianal. Caso clínico / Langerhans cell histiocytosis in a patient with perianal lesion. A case report

La histiocitosis de células de Langerhans es una expresión de células dendríticas mieloides, asociada a un componente inflamatorio significativo y compromiso sistémico variado. La edad más frecuente de presentación es entre 1 y 4 años, y predomina en el sexo masculino. Se comunica el caso de un niño de 5 años de edad cuya forma de presentación fue una lesión granulomatosa con fístula perianal, afectación pulmonar y de oído externo. El abordaje interdisciplinario permitió llegar al diagnóstico, realizar las intervenciones necesarias e iniciar el tratamiento adecuado.

Langerhans cell histiocytosis is an expression of myeloid dendritic cells, associated with a significant inflammatory component and varied systemic involvement. The most common age at presentation is between 1 and 4 years, and it prevails among male subjects. Here we describe the case of a 5-year-old boy who presented with a granulomatous lesion with perianal fistula and lung and external ear involvement. An interdisciplinary approach helped to make a diagnosis, provide the necessary interventions, and start an adequate treatment.

[Management of patients with complex ear deformities]. / Prise en charge des patients présentant des déformations complexes du pavillon de l'oreille.

Complex ear reconstruction requires specialized multidisciplinary care. Most patients present with microtia, often associated with hearing disorders. The management of these disorders is a priority, and reconstruction of the external ear remains optional. Nowadays, auricular reconstruction is based on the subcutaneous implantation of either autologous cartilage or an allogeneic implant. Autologous reconstruction requires highly specialized surgical expertise and involves harvesting rib cartilage but carries a lower risk of exposure compared to allogeneic implants. Both techniques yield good results with a high success rate and have a positive impact on the social functioning and daily life of patients.

La reconstruction complexe du pavillon auriculaire nécessite une prise en charge multidisciplinaire spécialisée. La majorité des patients nécessitant ce geste présentent une microtie, souvent associée à des troubles de l'audition. La prise en charge de ceux-ci est prioritaire et la reconstruction du pavillon reste facultative. Aujourd'hui, la reconstruction du pavillon se base sur l'implantation sous-cutanée d'une maquette de cartilage autologue ou d'un implant allogène. La reconstruction autologue demande une expertise chirurgicale hautement spécialisée et nécessite un prélèvement de cartilage costal mais présente un risque d'exposition inférieur par rapport à l'implant allogène. Les deux techniques permettent d'atteindre de bons résultats avec un taux de réussite élevé et un effet positif sur le fonctionnement social et le quotidien des patients.

Selecting Flap Transfer Methods to Repair Helix Soft Tissue Defect Based on the Direction of Long Axis.

BACKGROUND: The posterior auricular flap has long been favored for repairing skin defects on the ear's surface. However, achieving optimal esthetic outcomes in ear reconstruction requires a flexible approach to flap transfer methods. While bipedicle advancement flaps are commonly used for body wound coverage, they are rarely used in auricular defect repair. OBJECTIVE: To propose a modified flap transfer approach based on the orientation of the auricular defect's long axis and assess the postoperative esthetic outcomes. METHODS: The authors reported 12 patients treated using 2 distinct flap transfer techniques. Mild to moderate helix soft tissue defects remained after excision of the masses. A direct island flap was created for patients with longitudinal defects to cover the defect. For patients with transverse defects, a combination of bipedicle and island flaps was used for repair. Scar quality and esthetic outcomes were assessed at least 6 months postsurgery using the Scar Cosmesis Assessment and Rating scale. RESULTS: All patients experienced no serious complications and achieved excellent cosmetic results. Patients undergoing combined flap transfer exhibited relatively more favorable esthetic outcomes. CONCLUSION: The authors propose a novel concept for repairing helix soft tissue defects by designing local flaps based on the direction of the defect's long axis. For repairing helix soft tissue defects with a long axis parallel to the auricular edge, the combined utilization of bipedicle advancement flap and island rotation flap transfer should be consideration more.

Bilateral pyogranulomatous otitis externa with putative cartilage destruction in a dog: A severe case of auricular chondritis?

Auricular chondritis of unknown cause was suspected in a 10-year-old male Bolognese dog with a five-month history of painful bilateral nodular and ulcerative pyogranulomatous dermatitis of the pinnae with putative auricular cartilage destruction. Pain and lesions resolved with immunosuppressive doses of prednisolone, yet the condition resulted in deformity of both pinnae and external canals.

Une chondrite auriculaire d'étiologie inconnue est suspectée chez un bichon bolonais mâle de 10 ans qui présente depuis 5 mois une dermatite pyogranulomateuse nodulaire et ulcéreuse bilatérale douloureuse du pavillon de l'oreille avec une destruction présumée du cartilage auriculaire. La douleur et les lésions disparaissent avec des doses immunosuppressives de prednisolone, mais l'affection entraîne une déformation des deux pavillons et des conduits auriculaires externes.

Suspeitou­se de condrite auricular de causa desconhecida em um cão macho Bolonhês de 10 anos de idade com um histórico de cinco meses de dermatite piogranulomatosa ulcerativa e nodular bilateral no pavilhão auricular com suposta destruição de cartilagem auricular. A dor e as lesões resolveram com doses imunossupressoras de prednisolona apesar de a etiologia ter resultado na deformidade de ambas as orelhas e condutos auditivos.

Se sospechó la existencia de una condritis auricular de causa desconocida en un perro boloñés de 10 años con historia de 5 meses de duración de una dermatitis nodular ulcerativa piogramulomatosa y bilateral en las orejas con posible destrucción del cartílago auricular. El dolor y las lesiones se resolvieron con dosis inmunosupresoras de prednisolona pero la enfermedad produjo deformación de ambas orejas y de los canales auriculares externos.

Early Non-Surgical Treatment For Microtia Types 1 and 2.

Esthetic concerns and psychosocial distress often accompany auricular deformities and malformations in both children and their parents. Approximately 30% of newborns are affected by auricular anomalies, with 15% to 20% resulting in permanent defects. While surgical intervention is typically considered the gold standard for malformations, a non-surgical approach, such as splinting, molding, or other non-invasive techniques, can effectively address deformations if promptly administered by a specialist. Microtia, classified into 4 types, presents challenges ranging from fundamental structural anomalies in types 1 and 2 to severe defects in type 3 and complete absence of the external ear in type 4 (anotia). This study introduces a novel non-invasive treatment modality for microtia types 1 and 2. The cohort consisted of 5 newborns treated for microtia types 1 or 2 between 2022 and 2023. Utilizing the EarWell system, treatment was initiated before 3 weeks of age (mean age: 2 weeks), with an average treatment duration of 6.6 weeks, supplemented by molding treatment as needed. Minor adverse effects, such as simple dermatitis, were observed in 2 patients. All parents expressed high satisfaction with the esthetic outcomes, with 60% reporting extreme satisfaction. The prompt initiation of the treatment protocol for microtia types 1 and 2 led to outstanding and timely outcomes in infants, enhancing the quality of life for both parents and their children. Early intervention for subsequent treatment may improve the condition and, in certain cases, serve as a satisfactory alternative for parents hesitant about further surgical intervention for their children.

A rare cause of malignant otitis externa and skull base osteomyelitis.

An elderly male with type 2 diabetes presented with a 2-month history of otalgia and severe headaches. He was diagnosed with malignant otitis externa (MOE) and was commenced on empirical treatment with oral ciprofloxacin. Pseudomonas is the most common cause of MOE. A baseline CT scan was undertaken that demonstrated skull base osteomyelitis (SBO) due to findings of bone erosion at the mastoid tip and an infiltrating soft tissue mass eroding the clivus. Eight weeks later, he returned with worsening and bilateral symptoms of otitis externa, hearing loss, temporomandibular pain and dysfunction. Worsening and now bilateral malignant otitis externa were confirmed with an MRI scan that also demonstrated a small fluid collection in his left temporal region. The collection was aspirated and grew scedosporium apiospermum. He was diagnosed with fungal SBO and was commenced on treatment with the antifungal voriconazole, with significant improvement in symptoms and radiological findings. Fungal osteomyelitis is more likely in immunosuppressed patients, particularly those with type 2 diabetes. Fungal aetiology should be suspected in patients with progressive symptoms, despite treatment. A microbiology diagnosis of fungal SBO or MOE can be challenging to obtain and can lead to diagnostic delay. A sampling of the external auditory canal can aid in diagnosing MOE; however, scedosporium may also be isolated as a commensal organism. Aspirations from accessible fluid collections, infratemporal fossa needle sample and bone biopsy can provide material for diagnosis. Scedosporium is a rare cause of disease in humans, however, fungal infections are increasing in humans, due to an increase in susceptible populations. Scedosporium apiospermum is a rare cause of SBO and should be considered in patients not responding to standard treatment.

[A case of trichoblastoma of the auricular cavity and review of the literature].

Trichoblastoma（TB） is a rare germ cell skin adnexal tumor of the hair, and it is a rare follicular tumor of the skin that differentiates from the hair germ epithelium and is often regarded as a benign skin tumorHowever, it is poorly confined and has a local infiltrative growth pattern. tb occurs in the head and neck region, especially in the face, and presents clinically as a slow growing, well-defined and elevated nodule. TB is routinely treated surgically. Due to the lack of universally accepted treatment guidelines or protocols, the recurrence rate after surgery is high, which makes clinical cure more difficult. In this study, a 65-year-old female patient was found to have a swelling with recurrent rupture and pus flow from the right external auditory canal opening and the auricular cavity. After initial misdiagnosis as otitis externa, she was treated with conventional anti-infective therapy, but her symptoms did not resolve and gradually worsened before coming to our hospital. The condition presented in this case is relativelyrare,therepre,timely and accurate diagnosis and treatment are crucial for prognosis improvement of such diseases.

Retrospective study on unilateral polyotia combined with microtia utilizing the technique of preserving residual ear tissue.

BACKGROUND: The presence of polyotia in individuals with microtia is a rare deformity. Due to the intricate structure of the auricle, uncertain etiology, and challenging corrective techniques, it has always been a focal point in the field of plastic surgery. The present study presents a technique for correcting the combination of polyotia and microtia by utilizing residual ear tissue as graft material. METHODS: The retrospective study included 23 patients with polyotia and microtia from 2018 to 2022. The residual ear tissue was used to rectify auricular deformities in all patients. The patients were instructed to evaluate the satisfaction of the auricle shape using a visual analog scale (VAS) both before and 6 months after the surgical procedure. The esthetic outcomes of auricle subunits were simultaneously assessed by a senior physician pre- and postoperatively. RESULTS: The mean duration of follow-up in this study was 8.73 months. The preoperative VAS satisfaction score was recorded as 2.26 ± 0.86, while the post-operative VAS score significantly increased to 7.86 ± 0.86. The preoperative auricle esthetic outcomes score was recorded as 9.95 ± 1.74, while the post-operative score significantly increased to 24.04 ± 2.16. The follow-up period did not present any cases of flap necrosis, hematoma, infection, or wound dehiscence. CONCLUSION: The study demonstrates that comprehensive utilization of residual auricular tissue can lead to optimal outcomes in correcting polyotia with concha-type microtia. The utilization of residual ear tissue can be maximized to streamline the operation, minimize bodily harm, and enhance patient satisfaction.

Epidemiology of congenital malformations of the external ear in Hunan Province, China, from 2016 to 2020.

To describe the epidemiology of congenital malformations of the external ear (CMEE). Data were obtained from the Birth Defects Surveillance System in Hunan Province, China, 2016 to 2020. The prevalence of CMEEs is defined as the number of cases per 1000 fetuses (births and deaths at 28 weeks of gestation and beyond) (unit: ‰). Prevalence and 95% confidence intervals (CI) were calculated by the log-binomial method. Chi-square trend tests (χ2trend) were used to determine trends in prevalence by year. P < .05 was considered statistically significant. Crude odds ratios (ORs) were calculated to examine the association of sex, residence, and maternal age with CMEEs. Our study included 847,755 fetuses, and 14,459 birth defects were identified, including 1227 CMEEs (accounted for 8.49% of birth defects). The prevalences of birth defects and CMEEs were 17.06‰ (95%CI: 16.78-17.33) and 1.45‰ (95%CI: 1.37-1.53), respectively. A total of 185 microtia-anotias were identified, accounting for 15.08% of CMEEs, with a prevalence of 0.22‰ (95%CI: 0.19-0.25). And 1042 other CMEEs were identified, accounting for 84.92% of CMEEs. From 2016 to 2020, the prevalences of birth defects were 18.20‰, 18.00‰, 16.31‰, 16.03‰, and 16.47‰, respectively, showing a downward trend (χ2trend =8.45, P < .01); the prevalences of CMEEs were 1.19‰, 1.62‰, 1.80‰, 1.21‰, and 1.35‰, respectively, with no significant trend (χ2trend =0.09, P = .77). CMEEs were more common in males than females (1.60‰ vs 1.27‰, OR = 1.26, 95%CI: 1.12-1.41), in urban areas than in rural areas (1.77‰ vs 1.23‰, OR = 1.45, 95%CI: 1.29-1.62). The prevalences of CMEEs for maternal age < 20, 20-24, 25-29, 30-34, and ≥ 35 were 1.75‰, 1.27‰, 1.44‰, 1.47‰, and 1.58‰, respectively, with no significant difference (P > .05, reference: 25-29). Most CMEEs were diagnosed by clinical examinations (92.34%), and most CMEEs were diagnosed postpartum (within 7 days) (96.25%). In summary, we have presented the epidemiology of CMEEs in Hunan Province, China. CMEEs were more common in males than females, in urban areas than rural areas, whereas there was no significant difference in prevalence of CMEEs by maternal age. We inferred that CMEEs may be mainly related to genetics, and the mechanism needs to be examined in the future.

Identification of a novel phenotype of external ear deformity related to Coffin-Siris syndrome-9 and literature review.

De novo germline variants of the SRY-related HMG-box 11 gene (SOX11) have been reported to cause Coffin-Siris syndrome-9 (CSS-9), a rare congenital disorder associated with multiple organ malformations, including ear anomalies. Previous clinical and animal studies have found that intragenic pathogenic variant or haploinsufficiency in the SOX11 gene could cause inner ear malformation, but no studies to date have documented the external ear malformation caused by SOX11 deficiency. Here, we reported a Chinese male with unilateral microtia and bilateral sensorineural deafness who showed CSS-like manifestations, including dysmorphic facial features, impaired neurodevelopment, and fingers/toes malformations. Using trio-based whole-exome sequencing, a de novo missense variant in SOX11 (NM_003108.4: c.347A>G, p.Y116C) was identified and classified as pathogenic variant as per American College of Medical Genetics guidelines. Moreover, a systematic search of the literature yielded 12 publications that provided data of 55 SOX11 intragenic variants affecting various protein-coding regions of SOX11 protein. By quantitatively analyzing phenotypic spectrum information related to these 56 SOX11 variants (including our case), we found variants affecting different regions of SOX11 protein (high-mobility group [HMG] domain and non-HMG regions) appear to influence the phenotypic spectrum of organ malformations in CSS-9; variants altering the HMG domain were more likely to cause the widest range of organ anomalies. In summary, this is the first report of CSS with external ear malformation caused by pathogenic variant in SOX11, indicating that the SOX11 gene may be not only essential for the development of the inner ear but also critical for the morphogenesis of the external ear. In addition, thorough clinical examination is recommended for patients who carry pathogenic SOX11 variants that affect the HMG domain, as these variants may cause the widest range of organ anomalies underlying this condition.

New Method Using Local Affected Cartilage and Flap for the Cleft in Question Mark Ear.

BACKGROUND: As a rare auricular deformity, despite numerous surgical procedures for correcting moderate-to-severe question mark ears described in past studies, there remains a need to explore a more cost-effective approach. The optimal utilization of ear cartilage and surrounding skin while achieving superior outcomes continues to pose a significant challenge. METHODS: From 2018 to 2023, twenty-four patients with unilateral question mark ear were enrolled in this study. Seven of them were severe type deformities (absence of lower part of auricle), and seventeen were moderate (only cleft between helix and lobule). All patients were treated with new method using local cartilage and flap without damage in unaffected area. RESULTS: All patients were satisfied with significant improvement of question mark ear and the overall symmetrical appearance. The surgical scar was not obvious. No complications were observed. The follow-up period revealed that the corrective procedure kept producing the symmetrical and cosmetic results. CONCLUSION: Our new method enables optimal utilization of deformed tissue and surrounding skin, rendering this method effective and reliable for correcting moderate-to-severe question mark ears. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Antibacterial effects of chitosan-based hydrogels containing Trachyspermum ammi essential oil on pathogens isolated from dogs with otitis externa.

BACKGROUND: Growing antibiotic resistance has made treating otitis externa (OE) increasingly challenging. On the other hand, local antimicrobial treatments, especially those that combine essential oils (EOs) with nanoparticles, tend to be preferred over systemic ones. It was investigated whether Ajwain (Trachyspermum ammi) EO, combined with chitosan nanoparticles modified by cholesterol, could inhibit the growth of bacterial pathogens isolated from OE cases in dogs. In total, 57 dogs with clinical signs of OE were examined and bacteriologically tested. Hydrogels of Chitosan were synthesized by self-assembly and investigated. EO was extracted (Clevenger machine), and its ingredients were checked (GC-MS analysis) and encapsulated in chitosan-cholesterol nanoparticles. Disc-diffusion and broth Micro-dilution (MIC and MBC) examined its antimicrobial and therapeutic properties. RESULTS: Staphylococcus pseudintermedius (49.3%) was the most common bacteria isolated from OE cases, followed by Pseudomonas aeruginosa (14.7%), Escherichia coli (13.3%), Streptococcus canis (9.3%), Corynebacterium auriscanis (6.7%), Klebsiella pneumoniae (2.7%), Proteus mirabilis (2.7%), and Bacillus cereus (1.3%). The investigation into the antimicrobial properties of Ajwain EO encapsulated in chitosan nanoparticles revealed that it exhibited a more pronounced antimicrobial effect against the pathogens responsible for OE. CONCLUSIONS: Using chitosan nanoparticles encapsulated with EO presents an effective treatment approach for dogs with OE that conventional antimicrobial treatments have not cured. This approach not only enhances antibacterial effects but also reduces the required dosage of antimicrobials, potentially preventing the emergence of antimicrobial resistance.