American Cocker Spaniels (ACSs) develop aural ceruminous gland hyperplasia and ectasia more often than dogs of other breeds. Data on the cause and development of these breed characteristic histopathological changes are lacking. We performed video-otoscopic examinations and dermatological work-up on 28 ACSs, obtained aural biopsies from each dog and assessed the statistical associations between the presence of ceruminous gland hyperplasia and ectasia and disease history, clinical or microbiological findings and underlying cause of otitis externa (OE). Histological lesions of ceruminous gland hyperplasia and ectasia were observed in aural biopsies from 6/13 clinically healthy ears and 13/15 ears with OE from 19/28 examined dogs. Nine of 28 dogs had histologically normal ceruminous glands (odds ratio [OR] 6.2, 95% confidence interval [CI] 1.1–36.6). Bacterial growth in microbiological culture of aural exudate (OR 14.1, 95% CI 2.1–95.3) was associated with ceruminous glandular changes, whereas previous history of OE, cutaneous findings or underlying allergies were not. Pedigree analysis and a genome-wide association study (GWAS) were performed on 18 affected and eight unaffected dogs based on histopathological diagnosis. While the GWAS indicated a tentative, but not statistically significant, association of ceruminous gland hyperplasia and ectasia with chromosome 31, a larger cohort is needed to confirm this preliminary result. Based on our results, ceruminous gland hyperplasia and ectasia may also precede clinical signs of OE in ACSs and a genetic aetiological component is likely Further studies with larger cohorts are warranted to verify our preliminary results.

美国可卡犬 (ACS) 比其他品种的狗更容易发生听觉蜡样腺增生和扩张。缺乏关于这些品种特征性组织病理学变化的原因和发展的数据。我们对 28 只 ACS 进行了视频耳镜检查和皮肤病学检查，从每只狗身上获得了耳部活检，并评估了耵聍腺增生和扩张与疾病史、临床或微生物学发现以及外耳炎的根本原因之间的统计关联。 OE）。在 6/13 只临床健康耳朵和 13/15 只 OE 的 19/28 只受检犬的耳部活检中观察到了蜡样腺增生和扩张的组织学损伤。28 只狗中有 9 只具有组织学上正常的蜡样腺（优势比 [OR] 6.2，95% 置信区间 [CI] 1.1-36.6）。耳分泌物微生物培养中的细菌生长 (OR 14.1, 95% CI 2.1–95.3) 与蜡样腺体变化有关，而既往 OE 病史、皮肤表现或潜在过敏则不然。根据组织病理学诊断，对 18 只受影响和 8 只未受影响的狗进行了谱系分析和全基因组关联研究 (GWAS)。虽然 GWAS 表明耵聍腺增生和扩张与 31 号染色体存在初步但无统计学意义的关联，但需要更大的队列来证实这一初步结果。根据我们的结果，耵聍腺增生和扩张也可能先于 ACS 中 OE 的临床症状，并且可能存在遗传病因学成分。需要对更大的队列进行进一步研究以验证我们的初步结果。