猫慢性耳炎：原发、易感和持久因素的临床管理（2）

王帆

ChroniC otitis in Cats Clinical management of primary, predisposing and perpetuating factors

猫慢性耳炎：原发因素、易感因素和持久因素的临床管理

作者：Bailey Brame and Christine Cain

翻译：郑江涛 校对：王帆

Primary factors causing otitis

耳炎的原发病因

Parasites

寄生虫

Otodectes cynotis

耳螨

Otodectes cynotis is the most common primary cause of feline otitis externa and is implicated in 53–69% of clinical cases. Conventional wisdom holds that Otodectes mites are most common in young cats, though older cats may be more likely to have asymptomatic infestations. The reported prevalence of Otodectes mite infestation is highly variable in the published literature, ranging from 0.9% to 37%. This may be due to differences in populations evaluated (stray vs client-owned), diagnostic techniques and geographic region.

耳螨是猫外耳炎最常见的原发病因，临床病例发病率53-69%。传统观点认为耳螨在幼猫中最为常见，但年龄较大的猫可能更容易出现无症状感染。据报道，在已发表的文献中，耳螨感染的发病率差异很大，从0.9%到37%。这可能是由于研究对象（流浪猫与家养猫）、诊断技术和地域分布不同。

Patients with Otodectes mite infestation are usually affected bilaterally. They often present with otic pruritus and abundant dark brown ceruminous debris reminiscent of coffee grounds. One study found that 23% of cats with Otodectes mites were also affected in areas other than the ear canals, and feline chin acne has been associated with Otodectes mite infestation. Secondary bacterial or Malassezia infection may occur.

耳螨感染患猫通常是双耳患病。他们通常表现为耳部瘙痒和大量的深棕色耵聍碎屑，像咖啡渣。一项研究发现，23%患有耳螨的猫在耳道以外的其他部位也会患病，猫的下巴痤疮与耳螨感染有关。可能会发生继发细菌或马拉色菌感染。

Otodectes mites can be identified on otoscopy in 67–93% of cases, but the abundant dark cerumen present in most patients with otoacariasis may reduce the sensitivity of otoscopy. If mites are not seen on otoscopy, an ear mite preparation should be performed (see box below). In one study, collecting cerumen with a curette was more rewarding than with a cotton-tipped applicator, with 93% and 51% diagnostic sensitivity, respectively.

在67-93%的病例中，耳螨在耳镜检查中可见，但大多数耳螨病患猫的大量深色耵聍可能会降低耳镜检查的敏感性。如果耳镜检查未发现螨虫，应进行耳螨检查采样（见下框）。在一项研究中，用刮匙收集耵聍比用棉签更有效，诊断敏感性分别为93%和51%。

There are many products that are effective for the treatment of Otodectes mite infestation in cats. Historically, otic preparations have been used, but these products require repeated aural treatment, which may reduce compliance. Milbemycin oxime (0.1%, MilbeMite; Elanco) remains a clinically useful otic treatment because it is labeled for kittens as young as 4 weeks of age.

有许多产品可以有效治疗猫的耳螨感染。历史上，耳制剂已经被使用，但是这些产品需要重复的耳部治疗，这可能会降低依从性。米尔贝肟（0.1%）仍然是一种临床上有用的耳科治疗药，因为标签内可用于4周龄的幼猫。

Newer systemic products are dosed less frequently and are usually administered as a topical transdermal preparation, which may improve client compliance. Additionally, they will also treat mites that migrate outside of the ear canals (most frequently along the head and neck region) more effectively than otic preparations. A systematic review in 2016 of treatment efficacy for Otodectes mite infestation identified only two treatments with fair evidence supporting their efficacy: spot-on 10% imidacloprid with 1% moxidectin (Advantage Multi; Bayer) and selamectin (Revolution; Zoetis). More recently, researchers have investigated isoxazolines in cats with O cynotis. Afoxolaner (no product available labeled for use in cats), selamectin plus sarolaner (Revolution Plus; Zoetis), fluralaner (Bravecto; Merck) and fluralaner plus moxidectin (Bravecto Plus; Merck) resolved O cynotis infestations in cats after a single application.

较新的全身性产品给药频率较低，通常作为局部透皮制剂给药，这可能会提高客户的依从性。此外，它们还将比耳制剂更有效地治疗迁移到耳道外的螨虫（最常见的是沿着头部和颈部区域）。2016年，一项关于耳螨感染治疗效果的系统综述只确定了两种有充分证据支持其疗效的治疗方法：10%吡虫啉与1%莫西克汀和赛拉菌素。最近，研究了异恶唑啉对耳螨患猫的疗效，阿福拉纳（没有标签内可用于猫的产品）、赛拉菌素+沙罗拉纳、氟雷拉纳和氟雷拉纳+莫西克汀，在使用一次后都能治疗猫的耳螨感染。

Otodectes cynotis is the most common primary cause of feline otitis externa. 耳螨是猫外耳炎最常见的原发病因。

Technique for ear mite evaluation 1 Collect a sample of cerumen using a curette (preferred) or cotton-tipped applicator. 2 Apply the cerumen in a layer on the surface of a glass slide. 3 Add 1–2 drops of mineral oil, then apply a cover slip. 4 Use a microscope to scan the entire slide for mites: – use the x 10 objective; – lower the condenser; – close the iris diaphragm. < Do not forget also to evaluate for ear mites directly using an otoscope! 耳螨检查技术 1使用刮匙（首选）或棉签采集耵聍样本。 2在载玻片表面涂上一层耵聍。 3添加1–2滴矿物油，然后盖上盖玻片。 4使用显微镜扫描整个载玻片，检查是否有螨虫： –使用10倍物镜； –降低光源； –关闭聚光圈。 <不要忘记直接使用耳镜评估耳螨！

Demodex species

蠕形螨属

Demodex cati has been identified on ear mite preparations in cats and can be associated with ceruminous otitis externa, with or without pruritus. Infested cats may not show any signs of dermatological disease outside of the ear canal. Cats with generalized demodicosis owing to D cati should be evaluated for any disease that may cause immunosuppression. The prevalence of D cati infestation is ⩽1%. Demodex gatoi has been documented in an ear of a cat with otitis externa but is not commonly associated with otic disease. Isoxazolines are highly effective at treating demodicosis in the dog, and both fluralaner and sarolaner (in combination with selamectin) have been reported to be effective for treatment of feline demodicosis.

猫蠕形螨已在猫的耳螨检查中发现，并可能与伴有或不伴有瘙痒的外耳炎有关。被感染的猫在耳道外可能不会表现出任何皮肤病症状。由猫蠕形螨感染的全身性蠕形螨病患猫，应检查任何可能导致免疫抑制的疾病。猫蠕形螨感染发病率为≤1%。在一只外耳炎患猫的耳朵中发现了戈托伊蠕形螨，但通常与耳病无关。异恶唑啉在治疗犬蠕形螨病方面非常有效，据报道，氟雷拉纳和沙罗拉纳（与赛拉菌素联用）对治疗猫蠕形螨病有效。

Primary fungal disease

原发性真菌病

Dermatophytosis

皮肤癣菌病

The most common fungal disease in cats is dermatophytosis, involving Microsporum canis in particular. Dermatophytosis causes lesions of alopecia, erythema and scale, and should be considered as a differential in any cat presenting with pruritus or these non-specific skin lesions. One of the common sites for dermatophytic lesions is the ear, including the canal, pinna and surrounding skin, but it is uncommon to see dermatophytosis restricted to the ear canal. Identification of cats with dermatophytosis is important due to the risks of zoonosis and contagious spread in multi-cat environments. For comprehensive guidelines regarding the diagnosis and treatment of dermatophytosis, readers are referred to the 2017 clinical consensus document from the World Association for Veterinary Dermatology.

猫最常见的真菌病是皮肤癣菌病，尤其是犬小孢子菌。皮肤癣菌病导致脱毛、红斑和皮屑病变，应作为任何猫出现瘙痒或非特异性皮肤病变的鉴别诊断。皮肤癣菌病的病变常见部位之一是耳部，包括耳道、耳廓和周围皮肤，但局限于耳道内的皮肤癣菌病并不常见。由于在多猫环境中存在人畜共患病和传染病传播的风险，因此识别皮肤癣菌病患猫非常重要。关于皮肤癣菌病的诊断和治疗的综合指南，读者可参考世界兽医皮肤病学协会2017年的临床共识指南文章。

Other fungal diseases

其他真菌疾病

Less commonly, other fungal organisms may cause otomycosis. In a retrospective case series, Goodale et al described nine cats diagnosed with otitis externa with Aspergillus species isolated on culture; Aspergillus fumigatus was the most commonly isolated species. A single case of acute unilateral otitis externa caused by Sporothrix schenckii has been described in a 10-month-old cat in Brazil, which resolved after treatment with itraconazole. Chronic bilateral otitis interna caused by Cryptococcus neoformans var. grubii was identified at necropsy in a 7-year-old cat with a 9-day history of vestibular ataxia and head tilt. A prospective case series of 35 cats with cryptococcosis identified one cat for which the site of infection was the ears.

其他真菌微生物可能会导致的耳真菌病不常见。在一回顾性病例分析中，Goodale等描述了9只诊断为外耳炎的猫，其培养中分离出曲霉菌；烟曲霉菌是最常见的分离菌种。巴西一只10个月大的猫患有申克孢子丝菌引起的急性单侧外耳炎，经伊曲康唑治疗后痊愈。在一只7岁猫的尸检中发现新型隐球菌格鲁比亚种引起的慢性双侧内耳炎，这只猫有9天的前庭共济失调和头倾斜病史。35只患有隐球菌病的猫的前瞻性病例分析确定了一只猫的感染部位是耳朵。

Allergic skin disease

过敏性皮肤病

Among cats diagnosed with allergies at a veterinary teaching hospital, 17% had bacterial otitis externa, and 6% had Malassezia otitis externa. Otitis externa is most common in cats with feline atopic skin syndrome (formerly ‘non-flea non-food hypersensitivity dermatitis’) relative to cats with food allergy or flea allergy dermatitis, though it can occur with any type of allergic skin disease. Among cats with feline atopic syndrome, 16–20% had concurrent otitis externa.

在兽医教学医院诊断为过敏症的患猫中，17%患有细菌性外耳炎，6%患有马拉色菌外耳炎。相对于患有食物过敏或跳蚤叮咬过敏性皮炎的患猫，外耳炎在患有猫特应性皮肤综合征（以前称为“非跳蚤非食物过敏性皮炎”）的患猫中最为常见，但它可以发生在任何类型的过敏性皮肤病。在猫特应性综合征的患猫中，16-20%的猫同时患有外耳炎。

Allergic skin disease should be considered in cats where infection recurs after cytologic cure and where other causes have been excluded. Cats with otitis externa owing to allergies are likely to experience pruritus in other body regions, rather than having only otic disease. Control of otitis externa in a patient with allergic skin disease requires the underlying allergy to be addressed.

如果细胞学检查治愈后，感染再次复发，并且排除了其他病因，则应考虑猫过敏性皮肤病。由于过敏症导致的外耳炎患猫很可能在机体的其他部位出现瘙痒，而不是只有耳部疾病。控制过敏性皮肤病患猫的外耳炎需要解决潜在的过敏症。

When evaluating for food allergy in patients with otitis externa, it is important to resolve both infection and inflammation before assessing for response to diet change (and considering dietary rechallenge). This is because secondary infection is not expected to resolve without directed therapy. Additionally, owners may not appreciate worsening inflammation in the absence of infection, so it is recommended that patients be re-evaluated (physical examination and otoscopy) during the dietary rechallenge period.

在评估外耳炎患猫的食物过敏时，重点是在评估食物排除试验（并考虑食物激发试验）前先要解决感染和炎症反应。这是因为如果没有针对性的治疗，继发性感染不会得到缓解。此外，在没有感染的情况下，主人可能不会意识到炎症的恶化。因此，建议在食物激发试验期间对患猫进行再次评估（体检和耳镜检查）。

To control otitis in a patient with allergic skin disease, it is important to control the underlying allergy. 控制过敏性皮肤病患猫的耳炎，重点在管理潜在的过敏症。

Disorders of cornification

角化异常

Idiopathic ceruminous otitis

特发性耵聍性耳炎

Idiopathic ceruminous otitis is an over -production or accumulation of ceruminous debris that may predispose to secondary infections. It is poorly characterized in the literature, and there is disagreement among dermatologists as to whether it is an independent clinical entity. Idiopathic excessive cerumen production was described in nine cats with lifelong histories of increased cerumen bilaterally without clinical signs of otitis.

特发性耵聍性耳炎是耵聍碎片的过度产生或积聚，可能导致继发感染。它在文献中很少被描述，关于它是否是一个独立的临床疾病，皮肤科医生之间存在分歧。在9只猫中描述了特发性耵聍过度产生，这些猫终生有双侧耵聍增加的病史，但没有耳炎的临床症状。

Idiopathic facial dermatitis of Persian and Himalayan cats

波斯猫和喜马拉雅猫的特发性面部皮炎

Bond et al described a disorder affecting 13 Persian cats that developed black debris in the hair on their faces, which progressed to erythema and pruritus. Seven (54%) of the affected cats also had otitis externa, characterized by erythema and black waxy debris. The disease was progressive, and no cat responded completely to therapy with glucocorticoids and antimicrobials. In later case reports, affected cats showed a good response to oral ciclosporin, topical tacrolimus, and combination therapy with oral ciclosporin, dexamethasone and aggressive topical therapy. Though pathophysiology is not well characterized for this disease, the response to immunomodulatory therapy suggests that there may be an immune-mediated component (see ‘Immunemediated diseases’ section below).

Bond等人描述了一种影响13只波斯猫的疾病，其面部毛发中出现黑色碎屑，发展为红斑和瘙痒。7只（54%）患猫还有外耳炎，以红斑和黑色蜡状碎屑为特征。这种疾病是进行性的，没有一只猫对糖皮质激素和抗生素的治疗有完全的效果。在后来的病例报告中，患猫对口服环孢素表现出良好效果，外用他克莫司，以及口服环孢素和地塞米松和积极外部治疗的联合治疗。虽然这种疾病的病理生理学特征尚不明确，但对免疫调节治疗的效果表明可能存在免疫介导成分（见下文“免疫介导疾病”一节）。

Hypothyroidism

甲状腺功能减退

Spontaneous primary hypothyroidism is rare in adult cats, with only three cases reported in the literature. In two of these cases, the cats were diagnosed with concurrent chronic otitis externa. Cats with spontaneous hypo thyroidism tend to present with lethargy, weight gain, hypotrichosis, scale and an unkempt haircoat.

自发性原发性甲状腺功能减退症在成年猫中很罕见，文献中仅有3例报道。在其中两个病例中，猫被诊断为同时患有慢性外耳炎。患有自发性甲状腺功能减退的猫往往表现为嗜睡、体重增加、少毛症、皮屑和被毛蓬乱。

Congenital hypothyroidism may occur in kittens, and secondary hypothyroidism may occur as a result of trauma or from treatment of hyperthyroidism. Otitis externa has not been reported in association with congenital or secondary hypothyroidism in cats.

先天性甲状腺功能减退症可能发生在幼猫上，继发性甲状腺功能减退症可能由于创伤或治疗甲状腺功能亢进而发生。在猫中，报道外耳炎与先天性或继发性甲状腺功能减退无关。

Sebaceous gland disease

皮脂腺疾病

Overall, sebaceous gland disorders are rare in the cat. A case series involving 10 kittens with sebaceous gland dysplasia described crusting within the ear canals and on the pinnal margins, with one kitten developing severe otitis externa secondarily to the condition.

总的来说，皮脂腺疾病在猫上很罕见。一个10只患有皮脂腺发育不良的幼猫的病例分析描述了耳道内和耳廓边上的结痂，其中一只幼猫继发了严重的外耳炎。

Immune-mediated diseases

免疫介导性疾病

Proliferative and necrotizing otitis externa

增生性坏死性外耳炎

Proliferative and necrotizing otitis externa (PNOE) is a rare disease that affects the concave pinna and ear canal, causing proliferative plaques that develop thick, adherent, tan to dark brown layers of keratinaceous exudate (Figure 3a). Erosions or ulcers develop over time due to the friable proliferative tissue, which can cause pain and pruritus. Depending on severity, the ear canal may be occluded, predisposing cats to secondary infection.

增生性坏死性外耳炎（PNOE）是一种罕见的耳廓凹面及外耳道疾病。引起增殖性斑块，形成厚的、粘连的、棕褐色至深褐色的角质渗出物（图3A）。由于增生组织脆弱，随着时间的推移会出现糜烂或溃疡，这会引起疼痛和瘙痒。根据严重程度，耳道可能被堵塞，使猫容易继发感染。

Figure 3 Proliferative and necrotizing otitis externa in a 1-year-old castrated male Siamese cat; (a) at initial presentation and (b) after 1 month of therapy with oral ciclosporin, topical tacrolimus 0.1% ointment, and systemic and topical antimicrobials to treat secondary infection

图3。一只1岁已去势雄性暹罗猫的增生性坏死性外耳炎。（a）首诊时表现和（B）口服环孢素、外用0.1%他克莫司软膏以及全身和外用抗菌药物治疗继发感染1个月后表现。

In one cat, the ear canal was severely affected while the pinna was spared. In a kitten with otitis externa, lesions histologically consistent with PNOE developed on the face, though the canals did not have proliferative or necrotic tissue.

在一只猫中，耳道严重患病，而耳廓无病变。在一只患有外耳炎的幼猫中，尽管耳道没有增生或坏死组织，但其面部的病变在组织学上与PNOE一致。

Though initially described in kittens under a year old, PNOE has been documented in young adult cats. This disease may spontaneously resolve in kittens or may persist into adulthood. Biopsy is required for definitive diagnosis.

虽然PNOE最初在一岁以下的幼猫中被描述，但在年轻的成年猫中也有记录。这种疾病可能会在幼猫身上自行消退，也可能会持续到成年。确诊需要活组织检查。

The most common therapies reported in the literature are topical tacrolimus and topical and systemic glucocorticoids. One of the authors (CC) has successfully treated a few severely affected young adult cats with systemic ciclosporin (Figure 3b). The clinician should evaluate for secondary infection and address it if present.

文献中报道的最常见的治疗方法是外用他克莫司以及外用和全身用糖皮质激素。其中一位作者（CC）已经成功地用全身性环孢素治疗了几只严重患病的年轻成年猫（图3B）。临床医生应评估继发感染，并在出现继发感染时予以处理。

Pemphigus foliaceus

落叶型天疱疮

Pemphigus foliaceus (PF) is the most common autoimmune skin disease of cats. Though 80–92% of cats with PF have pinnal lesions, the ear canal is less frequently affected. Otitis externa has been reported in 7–30% of cats with PF. Most cats with PF have lesions affecting multiple sites. The primary lesion of PF is a subcorneal pustule, but these are prone to rupture, so crusts, erosions, alopecia and erythema are more often seen clinically. Otitis externa secondary to PF typically resolves with infection control and treatment of the underlying disease.

落叶型天疱疮（PF）是猫最常见的自体免疫性皮肤病。虽然80-92%PF患猫有耳廓病变，但耳道较少患病。据报道，7-30%PF患猫有外耳炎。大多数PF患猫都多个部位有病变。PF的原发病变是角质层下脓疱，但这些脓疱容易破裂，因此临床上更常见到结痂、糜烂、脱毛和红斑。继发于PF的外耳炎通常通过控制感染和治疗潜在疾病得以缓解。

PF is most commonly treated with corticosteroids, and monotherapy is effective at inducing remission in 62–70% of affected cats. If corticosteroid monotherapy is insufficient or steroid side effects occur, an alternative or secondary immunomodulatory medication may be used. The immunomodulatory agents with the strongest evidence in feline PF are ciclosporin and chlorambucil. Relapse is common in cats with PF, occurring in 27-95% of cases, particularly when medications are tapered or discontinued.

PF最常用皮质类固醇治疗，单一疗法可有效缓解62-70%患猫的病情。如果皮质类固醇单一疗法不足或出现类固醇副作用，可以使用替代或辅助免疫调节药物。环孢素和苯丁酸氮芥是猫PF中最有效的免疫调节剂。PF患猫常见复发，27-95%的病例复发，特别是当药物逐渐减少或停止时。

Vet武