皮肤是猫咪健康状况的标志-全身性疾病的皮肤表现（6）

王帆

皮肤是猫咪健康状况的标志

SKIN AS A MARKER OF GENERAL FELINE HEALTH

全身性疾病的皮肤表现

Cutaneous manifestations of systemic disease

作者：Linda J Vogelnest

翻译：何梦婷  校对：王帆

有结节和/或结节性肿胀的患猫

The cat with nodules and/or nodular swelling

产生结节和结节性肿胀的深层皮肤病通常分为三种主要病因：感染性、炎性或肿瘤性。一些病变类型和分布更能够提示某些诊断，但许多结节性皮肤病外观相似。最佳治疗方案、全身患病可能性和预后差异很大，因此及时确诊非常重要。

Deeper skin diseases that produce nodules and nodular swelling generally fall into three main aetiological groups: infectious, inflammatory or neoplastic. Some lesional types and distributions may be more suggestive of certain diagnoses, but many nodular skin diseases appear similar. Optimal treatments, likelihood of systemic involvement and prognosis vary widely, and thus prompt confirmation of diagnosis is important.

感染性疾病

Infectious disease

许多感染源都可能会产生结节性病变。包括葡萄球菌（例如：下巴深层脓皮病）在内的一些感染性病因。许多原发性条件致病病原也会导致在猫结节性皮肤病，特别是当创伤后植入时。有些与重要的全身性疾病有关。

A broad range of infectious agents may produce nodular lesions. Some infectious causes, including staphylococcal bacteria (eg, deep pyoderma of the chin), remain localised. A number of primarily opportunistic pathogens also cause nodular skin disease in the cat, typically when traumatically implanted. Some have important systemic disease associations.

分枝杆菌

Mycobacteria

最常见的猫分枝杆菌感染表现为缓慢进行的、界限不清的、不规则结节性病变，伴有点状瘘道，最常见位于尾腹部和腹股沟区域。感染源为腐生分枝杆菌（如：偶发分枝杆菌、龟头分枝杆菌、包皮垢分枝杆菌），广泛分布于环境中，在实验室中容易生长。这些分枝杆菌最常在免疫能力强的宿主中引起局部皮肤病，但偶见免疫力降低的患病动物。更罕见的是，局限于某些地理区域的分枝杆菌会引起更分散的皮肤结节，通常会散布到其他机体器官。

The most common feline mycobacterial infections present with slowly progressive, poorly demarcated, irregularly nodular lesions with punctate draining tracts, most typically in the caudal abdominal and inguinal areas. The infectious agents are saprophytic mycobacteria (eg, Mycobacterium fortuitum, Mycobacterium chelonae, Mycobacterium smegmatis) that are widely distributed in the environment, and grow readily in the laboratory. These mycobacteria most often cause localised cutaneous disease in immunocompetent hosts, but occasional dissemination occurs in immunocompromised patients.More rarely, mycobacteria restricted to certain geographic regions cause more discrete skin nodules, often with dissemination to other body organs.

在免疫低下的猫广泛传播的是典型的结核分枝杆菌（如牛分枝杆菌、结核分枝杆菌、小分枝杆菌）。这些都是专性动物病原，与严重的人畜共患病有关，在某些环境物种病例中，具有更高的选择致病性（例如，家族性年轻阿比西尼亚猫和索马里猫中的鸟分枝杆菌复合物、长期感染FIV的成年猫的日内瓦分枝杆菌和可见分枝杆菌）。大多数患有这些分枝杆菌感染的猫除了典型的分散性皮肤结节外，还有全身疾病（呼吸系统、胃肠道）和淋巴结肿大，这些结节可能有溃疡或没有溃疡。

Widespread dissemination in immunocompromised cats is typical with the classical‘ tuberculous’ mycobacteria (eg, Mycobacterium bovis, Mycobacterium tuberculosis, Mycobacterium microti). These are obligate animal pathogens associated with severe zoonotic potential and, in the case of some environmental species, with more selective pathogenicity (eg, Mycobacterium avium complex in familial young Abyssinian and Somali cats, Mycobacterium genavense in old cats with longstanding FIV, and Mycobacterium visibile). Most cats with these mycobacterial infections have signs of systemic illness (respiratory, gastrointestinal) and lymphadenopathy in addition to typically discrete skin nodules, which may or may not ulcerate.

猫麻风病是由难培养的分枝杆菌引起的，这种分枝杆菌通常不会在实验室培养基上生长（例如，麻风分枝杆菌、可见分枝杆菌）。感染很罕见，最常见于有户外生活的健康猫中（通常是捕猎猫）。这些分枝杆菌的宿主目前未知，但是，感染似乎与啮齿动物咬伤有关（麻风分枝杆菌），或外伤性植入物（暂命名：tarwinense分枝杆菌、可见分枝杆菌、暂命名：猫麻风分枝杆菌）。感染患猫可出现局灶性结节（暂命名：tarwinense分枝杆菌、麻风分枝杆菌）或大面积结节（暂命名：猫麻风分枝杆菌、可见分枝杆菌），偶见发展为全身性疾病。（有关进一步的讨论，请参阅随附的关于感染性疾病皮肤表现的文章。）

Feline leprosy is caused by fastidious mycobacteria that will not routinely grow on laboratory media (eg, Mycobacterium lepraemurium, M visibile). Infections are rare and most typical in healthy cats with outdoor exposure (often hunters). The reservoir of these mycobacteria is currently unknown; however, infection appears to be associated with rodent bites (M lepraemurium), or traumatic implantation (Candidatus ‘Mycobacterium tarwinense’, M visibile, Candidatus‘ Mycobacterium lepraefelis’). Infected cats may present with localised nodules (Candidatus‘M tarwinense’, M lepraemurium), or widespread nodules (Candidatus‘M lepraefelis’, M visibile) that occasionally progress to systemic disease.(See accompanying article on cutaneous manifestations of infectious disease for further discussion.)

诺卡氏菌

Nocardiaspecies

诺卡氏菌是普遍存在的环境细菌腐生菌，通过皮肤伤口植入或吸入后，偶见导致免疫力低下猫感染。 典型的表现是进行性不规则结节和典型点状瘘道，通常伴有肺部感染或大面积扩散。感染可能始于分散的脓肿，逐渐扩大。通常四肢，腹部腹侧和腹股沟区域患病，并且通常伴有淋巴结肿大。

Nocardian species are ubiquitous environmental bacterial saprophytes that very occasionally cause infection in immunocompromised cats, following implantation via skin wounds or inhalation. Progressive irregular nodules and punctate draining sinuses are typical, often with lung infection or widespread dissemination. Infections may start with discrete abscesses that gradually extend. The extremities, ventral abdomen and inguinal areas are typically affected, and lymphadenopathy is common.

环境真菌

Environmental fungi

皮肤破溃时，偶见多种环境真菌导致皮肤感染。虽然许多感染是局限性的，但某些具有全球分布变化的真菌物种会在猫中偶发，严重的弥散性感染可能表现为明显的结节性皮肤病。这些更具致病性的真菌物种包括在世界上适宜它们生存的环境中发现的隐球菌属和孢子菌属，以及在极端地理环境中出现的芽孢杆菌属、组织胞浆菌属和球孢子菌属。这些感染常见全身性表现，呼吸道、眼部和中枢神经系统最常患病。皮肤结节通常发生在四肢（面部、耳廓和足部）。

There are multiple environmental fungi that will occasionally cause infections when skin penetration occurs. Although many infections remain localised, some fungal species with varying global distributions cause sporadic but serious disseminated infections in cats that may present as prominent nodular skin lesions. These more pathogenic fungal species include Cryptococcus species and Sporothrix species, found in their preferred environmental niches worldwide, and Blastomyces species, Histoplasma species and Coccidioides species that occur in very restricted geographical locations. Systemic involvement with these infections is common, with the respiratory tract, eyes and central nervous system most frequently affected. Skin nodules tend to occur on extremities (face, pinnae and feet).

原虫

Protozoa

猫的利什曼病可表现为结节病变，可能溃疡，伴或不伴其他皮肤病变，包括脱毛、皮屑、丘疹、糜烂和溃疡。许多感染是弥散性的。猫弓形虫病非常罕见，通常与免疫功能低下有关，最常见的症状是全身症状（萎靡和发热，有或没有呼吸道、胃肠道、神经或眼部症状）。罕见引起皮肤结节，通常是多发性的，可能会溃疡。

Leishmaniosis in cats can present with nodules that may ulcerate, with or without other skin lesions that include alopecia, scaling, papules, erosions and ulceration. Many infections are disseminated. Toxoplasmosis in cats is very rare, usually associated with immunocompromise, and most frequently presents with systemic signs (malaise and fever, with or without respiratory, gastrointestinal, neurological or ocular signs). Skin nodules occur rarely, are typically multiple and may ulcerate.

所有表现结节性皮肤病，特别是多灶性病变的患猫，都可能有潜在的全身性疾病。

Any cat presenting with nodular skin disease, particularly with multiple lesions, has potential for systemic involvement.

炎性疾病

Inflammatory disease

猫的一些结节性病变起源于炎症，包括嗜酸性肉芽肿和斑块，经常与潜在的过敏反应有关。罕见的无菌炎性病变可能与全身性疾病有关。

Some nodular lesions in cats are inflammatory in origin, including eosinophilic granulomas and plaques, which are very frequently associated with underlying hypersensitivity. Rare sterile inflammatory lesions may be associated with systemic disease.

无菌性脂膜炎

Sterile panniculitis

脂膜炎在猫上非常罕见，与日粮不均（例如维生素E缺乏症，以鱼为食）和无菌性特发性形式有关，但也可能与胰腺炎或胰腺肿瘤有关。各种形式的病变均常见于腹部腹侧或胸部腹外侧区域。它们表现为单个或多个不规则结节区域，有或无瘘道，临床上需与感染性病因（包括分枝杆菌和诺卡氏菌）导致的脂膜炎进行鉴别诊断。

Panniculitis is reported very occasionally in cats, associated with dietary imbalance (vitamin E deficiency with, for example, exclusively fish diets) and as a sterile idiopathic form, but may also be associated with pancreatitis or pancreatic neoplasia. Lesions in all forms are reported more frequently in the ventral abdominal or ventrolateral thorax regions; they appear as single or multiple irregularly nodular regions, with or without draining tracts, that are clinically in distinguishable from infectious causes of panniculitis including mycobacteria and Nocardia species.

黄瘤

Xanthoma

在脂质代谢异常的猫（包括遗传性高脂血症和糖尿病）中，很少会出现多灶性浅黄色到粉红色的斑块至完整或溃疡的结节。病变常见于头部和四肢远端，可能瘙痒。已描述了一种非典型的特发性表现，在正常血脂猫中具有较多的弥散性的不规则结节性淡黄色区域。这些病变具有组织病理学特征表现，并且通过皮肤活检诊断黄瘤还需要进行系统评估（图11）。

Multiple pale yellow to pink plaques through to intact or ulcerated nodules occur rarely in cats with abnormalities in lipid metabolism, including hereditary hyperlipidaemia and diabetes mellitus. Lesions are most frequent on the head and distal extremities, and may be pruritic. One atypical idiopathic presentation has been described with more diffuse irregularly nodular yellowish regions in a normolipaemic cat.These lesions produce characteristic histopathology , and diagnosis of xanthoma from skin biopsies warrants systemic evaluation (Figure 11).

图11一只1岁家养短毛猫，因家族性高甘油三酯血症而出现皮肤黄瘤，其眼周背侧、耳廓和前额多灶性红斑块。

Figure 11 Multifocal erythemic plaques on the dorsal periocular areas, pinnae and forehead of a 1-year-old domestic shorthair cat with cutaneous xanthomas due to familial hypertriglyceridaemia

肿瘤

Neoplasia

肿瘤性结节性皮肤病变类似于感染性和炎性结节。虽然猫的皮肤肿瘤比犬的更常见为恶性，但许多形式是局部侵袭性的，转移的风险很低。具有较高转移风险的侵袭性形式包括一些肥大细胞瘤（图12）、恶性黑色素瘤和组织细胞肉瘤。

Neoplastic nodular skin lesions mimic infectious and inflammatory nodules. Although skin neoplasia in cats is more frequently malignant than in dogs, many forms are locally aggressive with a low risk of metastasis. Aggressive forms with a higher risk of metastasis include some mast cell tumours (Figure 12), malignant melanoma and histiocytic sarcomas.

图12一只12岁的家养短毛猫组织型肥大细胞瘤，病变呈多灶性分散性结节，有些伴有局灶性结痂。

Figure 12 Multifocal discrete nodules, some with focal crusting, in a 12-year-old domestic shorthair cat with histiocytic mast cell neoplasia.

诊断方法：结节和/或结节性肿胀 Diagnostics: nodules and/or nodular swelling 所有出现结节性皮肤病的患猫，特别是表现为多灶性病变，都可能有全身性疾病。全面的体格检查，包括眼部和口咽部检查，对于其他器官疾病评估很重要。猫的孢子丝菌病是一种具有严重人畜共患病可能的疾病； 在可疑病例（例如，所有具有溃疡性结节性病变的猫，尤其是在流行地区），护理恰当很重要，以避免接触病变皮肤和渗出液。 Any cat presenting with nodular skin disease, particularly with multiple lesions, has potential for systemic involvement. Full physical examination, including ocular and oropharyngeal examinations, is important to screen for evidence of other organ disease. Sporotrichosis in cats is a disease with serious zoonotic potential; appropriate care is important to avoid contact with skin lesions and exudate in suspect cases (eg, any cat with ulcerative nodular lesions, but particularly in endemic areas).    通常在进行更具侵入性的检查之前，建议对所有结节性病变进行细针穿刺细胞学检查，有时能够确诊，并经常提供有价值的诊断和预后指导。应该从多个病变中进行多次采样，在大病变边缘采样以避开中央坏死区域，从所有完整区域取样包含渗出物。如果抽次没有采集到细胞，则针头换位置重复穿刺（针尖在一个肿块内多次换位采样）可能会提供更高的样本。由于非特异性炎症和污染微生物的存在，通过从溃疡区域或瘘道进行拭子和压片取样提供的有用信息较少。通过经验丰富的细胞学家判读并提供临床背景信息将最大限度地提高诊断准确性。 Cytology via fine-needle aspiration is usually indicated for all nodular lesions prior to more invasive tests, and will sometimes confirm a diagnosis, and often provide valuable diagnostic and prognostic guidance. Multiple samples should be obtained from a range of lesions, sampling more peripherally in large lesions to avoid central areas of necrosis, and from any intact areas containing exudate. If cells are not obtained via aspiration, repeated needle fenestration (repositioning the needle tip multiple times within a mass) might provide higher yield. Sampling via swabs or impression smears from ulcerated regions or draining tracts provides less useful information due to non-specific inflammation and contaminant microbes. Utilising an experienced cytologist and providing clinical background will maximise diagnostic accuracy. 肉芽肿性或脓性肉芽肿性炎症很常见，大多伴有不同的感染源，但也可能会伴随无菌性炎症，并可能使某些肿瘤性病变复杂化。一些感染性微生物可能非常稀疏和/或需要特殊染色才能显现（例如：分枝杆菌属、诺卡氏菌属、隐球菌属）。当微生物丰富或从完整区域获得渗出液时，吸出的样品也可用于微生物培养（例如：快速生长的分枝杆菌）。 Granulomatous or pyogranulomatous inflammation is common with most of the infectious differentials, but will also occur with sterile inflammatory causes, and can complicate some neoplastic lesions. Some infectious organisms may be very sparse and/or require special stains to visualise (eg, mycobacteria, Nocardia species, Cryptococcus species). Aspirated samples may also be useful for microbial culture when organisms are plentiful or when exudate is obtainable from intact regions (eg, rapidly growing mycobacteria). 许多结节性表现需要活检和组织病理学检查才能确诊（图13），某些感染病因需要进行培养或分子学检测才能准确和/或鉴定出感染原及种属。但是，不建议对某些物种进行培养包括能引起悬浮微粒人畜共患病风险的孢子丝菌、芽生菌、球孢子菌和组织胞浆菌。收集两份无菌活检样本（或部分样本）进行冷冻（用于PCR检测，特殊培养）和一个无菌样本进行冷藏（用于微生物培养）可能很有价值，另外采集2-3处样本放入常规的福尔马林中用作组织病理检查。虽然当怀疑有感染性疾病时，这种方法尤其重要，但是这种方式已经被推荐用于皮肤/皮下结节和淋巴结肿大的患猫。 Many nodular presentations will require biopsy and histopathology for definitive diagnosis (Figure 13), and some infectious causes will require culture or molecular testing to confirm and/or identify infectious agents accurately and to species level. However, culture is not recommended for some species including Sporothrix, Blastomyces, Coccidiomyces and Histoplasma due to aerosol zoonotic risks. It may be valuable to collect two sterile biopsy samples (or portions of samples) for freezing (for PCR testing, specialist culture), and one sterile sample for refrigeration (for microbial culture), in addition to two to three samples in formalin for routine histopathology. This is particularly relevant when infectious diseases are suspected, although has been recommended for all cutaneous/ subcutaneous nodules, and for enlarged lymph nodes in cats. 图13 图12的患猫的胫骨外侧区域有部分脱毛和轻度局灶性结痂的结节。弥散性感染性病因(分枝杆菌、真菌、原虫)是除肿瘤病因外的首要考虑因素。肥大细胞瘤分化不良、无颗粒、常规染色不易检出。 Figure 13 Nodule with partial alopecia and mild focal crusting on the lateral tibial region of the cat pictured also in Figure 12. Disseminated infectious causes (mycobacteria, fungae, protozoa) were initial considerations in addition to neoplastic causes. The neoplastic mast cells were poorly differentiated and agranular, and not readily detected on routine staining.

重点 <皮肤可能是全身健康的重要标志，皮肤和被毛的变化有时可能是重要的全身性疾病的早期表现。 <所有皮肤病患猫都应该对病史和体格检查进行筛查，以寻找不符合常见的仅限皮肤发病的皮肤病的线索，并怀疑是否是全身性疾病。这些结果结合皮肤表现，可指导最适当的附加诊断。 <仔细调查日粮不均，传染性感染性疾病风险和全身性疾病症状，对于出现毛发无光泽、粗乱的患猫来说是很重要。 <细胞学和皮肤活检通常对结节性和糜烂性到溃疡性皮肤表现最为重要，以区分感染性、无菌性和肿瘤性病因，以及与不同的全身性疾病的相关性。 <对于瘙痒患猫，虽然皮肤过敏反应非常常见，但一些继发性和原发性感染可能与过敏症状相似，并与潜在的全身性疾病有关。因此，对非典型表现保持警觉，并意识到潜在感染与潜在全身性疾病的联系很重要。 <与全身性疾病相关的最具挑战性的皮肤病学表现是猫的脱毛、红斑、皮屑和局灶性结节的不同组合表现；过敏反应、感染、自体免疫性疾病和全身性疾病都应考虑在内。在这种情况下，对常见皮肤病的广全面了解将有助于识别不太一致的病史或病变信息，从而提高全身性疾病的识别，而准确的细胞学检查技术将有助于排除常见的感染性病因。两者都是更准确评估潜在全身性疾病的关键。

KEY POINTS < Skin can be an important marker of general health, and skin and haircoat changes can at times be the first indication of significant systemic disease. < Any cat presenting with skin disease should have screening of both the history and physical examination for clues that are less consistent with common skin-restricted dermatoses and that may raise suspicion for systemic disease. These findings, together with the skin presentation, then guide the most appropriate additional diagnostics. < Careful screening for dietary imbalance, risks of contagious infection and signs of systemic disease are important for the cat presenting with a dull, unkempt coat. < Cytology and skin biopsies are often most important for both nodular and erosive to ulcerative presentations to distinguish between infectious, sterile and neoplastic causes, with their variable systemic disease associations. < For the pruritic cat, although cutaneous hypersensitivities are very common, some secondary and primary infections may mimic allergic causes and be associated with underlying systemic illness. Thus, remaining alert for atypical presentations and cognisant of potential links of infection with underlying systemic disease is important. < Possibly the most challenging dermatological presentation to correctly associate with systemic disease is the cat with variable combinations of alopecia, erythema, scaling and focal crusting; where hypersensititives, infections, autoimmune diseases and systemic diseases are all considerations. In this scenario, a broad knowledge of common dermatoses will help with recognition of less consistent historical or lesional clues to raise the profile of systemic diseases, and accurate cytology skills will help exclude common infectious causes. Both are key to more accurate assessment of the potential for underlying systemic disease.