Antifollicular cell-mediated and humoral immunity in canine alopecia areata

Abstract A combination of cellular and humoral immunological assaults directed against follicular matrical cells is suspected to cause alopecia areata (AA) in humans. The specific aims of this study were to determine whether cytotoxic T lymphocytes (CTL) were increased in the blood and skin lesions of canine AA. Additionally, we wished to determine if circulating antifollicular antibodies were present in the dog. Finally, we aimed to investigate whether bulbar inflammation was associated with decreased matrical cell proliferation and keratinocyte apoptosis. Canine AA lesions were infiltrated by intrabulbar CTL, perifollicular helper T cells and dendritic cells. A higher percentage of CTL was present in canine AA peripheral blood compared with that of normal dogs. Tissue-fixed and circulating antifollicular IgG antibodies were detected. Reduced matrical proliferation and increased keratinocyte apoptosis was observed in inflamed hair bulbs. This study demonstrates the existence of antifollicular cell-mediated and humoral immunological responses in canine AA. Résumé— L'association d'agressions immunologiques cellulaires et humorales dirigées contre les cellules matricielles folliculaires est suspectée d'être à l'origine de l'Alopécie Areata chez l'homme. Le but de cette étude était de montrer si le nombre de lymphocytes T cytotoxiques est augmenté dans le sang et dans les lésions cutanées lors d'Alopécie Areata chez le chien. En plus, nous souhaitions montrer la présence d'anticorps circulants antifolliculaire chez le chien. Enfin, nous voulions voir si l'inflammation du bulbe pileux était associée à une diminution de la prolifération des cellules matricielles et une apoptose des kératinocytes. Lors d'Alopécie Areata chez le chien, existe une infiltration lésionnelle par des lymphocytes T cytotoxiques intrabulbaires, des lymphocytes T auxiliaires périfolliculaires et des cellules dentritiques. Le pourcentage de lymphocytes T cytotoxiques était plus important dans le sang périphérique provenant de sujets à Alopécie Areata que dans le sang d'animaux sains. Par ailleurs, des anticorps antifolliculaire (IgG) circulants et fixés dans les tissus sont détectés. Une réduction de la prolifération des cellules matricielles et une augmentation de l'apoptose des kératinocytes sont observées dans les bulbes pileux atteints. Cette étude démontre l'existence de réponses immunologiques cellulaires et humorales contre le follicule pileux dans l'Alopécie Areata du chien. [Olivry, T., Moore, P.F., Naydan, D.K., Puget, B.J., Affolter, V.K., Kline, A.E. Antifollicular cell-mediated and humoral immunity in canine alopecia areata (Immunité contre le follicule pileux dans l'Alopécie Areata du chien). Veterinary Dermatology 1996; 7 : 67–79.] Resumen Se cree que la alopecia areata (AA) en la especie humana resulta de la combinación de la acción inmunológica celular y humoral contra células de la matriz folicular. Los objetivos especificos de este estudio fueron determinar si los linfocitos T citotóxicos (CTL) se encontraban aumentados en sangre y en las lesiones cutáneas de animales con AA. Además, descamos investigar la posible presencia de anticuerpos antifoliculares circulantes en el perro. Finalmente, nos propusimos investigar si la inflamación bulbar se encontraba asociada a una disminución en la proliferación de células de la matriz y a la apoptosis de queratinocitos. Las lesiones de la AA canina mostraban infiltración por CTL intrabulbares, células T colaboradoras y células dendríticas. Se encontró un porcentaje mayor de CTL en la sangre periférica de perros con AA respecto a perros normales. Se detectaron anticuerpos IgG antifoliculares circulantes y en tejido fijado. Se observó una disminución en la proliferación matrical y un aumento en queratinocitos apoptóticos en los bulbos foliculares inflamados. Este estudio demuestra la existencia de respuestas inmunitarias antifoliculares de tipo celular y humoral en la AA canina. [Olivry, T., Moore, P.F., Naydan, D.K., Puget, B.J., Affolter, V.K., Kline, A.E. Antifollicular cell-mediated and humoral immunity in canine alopecia areata (Immunidad antifolicular en la alopecia areata canina). Veterinary Dermatology 1996; 7 : 67–79.] Zusammenfassung— Eine Kombinaton von zellulären und humoralen immunologischen Angriffen, die gegen die follikulären Matrixzellen gerichtet sind, wird als Ursache bei der Alopecia areata (AA) des Menschen vermutet. Die besondere Absicht dieser Studie war, festzustellen, ob die zytotoxischen T-Lymphozyten (CTL) im Blut und in den Hautveränderungen bei kaniner AA erhöht sind. Zusätzlich wollten wir feststellen, ob beim Hund zirkulierende antifollikuläre Antikörper vorkommen. Schließlich beabsichtigten wir, zu untersuchen, ob die bulbäre Entzündung mit verminderter Matrixzellproliferation und Keratinozytenapoptose einhergeht. Die Veränderungen bei kaniner AA wurden von intrabulbären CTL, perifollikulären T-Helferzellen und dendritischen Zellen infiltriert. Verglichen mit dem peripheren Blut gesunder Hunde kam bei kaniner AA eine höherer Prozentsatz an CTL vor. Es wurden gewebsfixierte und zirkulierende antifollikuläre IgG-Antikörper festgestellt. In entzündeten Haarbulbi wurde eine reduzierte Matrixproliferation und eine erhöhte Keratinozytenapoptose beobachtet. Diese Studie zeigt die Existenz von antifollikulären zellvermittelten und humoralen immunologischen Reaktionen bei kaniner AA. [Olivry, T., Moore, P. F., Naydan, D. K., Puget, B. J., Affolter, V. K., Kline, A. E. Antifollicular immunity in canine alopecia areata (Antifollikuläre Immunität bei der Alopecia areata des Hundes). Veterinary Dermatology 1996; 7 : 67–79.]     

Haptoglobin concentrations in dogs undergoing trilostane treatment for hyperadrenocorticism

BACKGROUND: Increased concentrations of haptoglobin (Hp), a moderate acute phase protein, have been demonstrated in dogs with hyperadrenocorticism (HAC). Monitoring serum concentrations of Hp in hyperadrenocorticoid dogs before and after trilostane administration may provide valuable information on the response to therapy. OBJECTIVE: The aim of this study was to measure Hp concentrations in dogs with spontaneously occurring HAC at the time of diagnosis and after treatment with trilostane. METHODS: Serum Hp concentration was measured using an automatic biochemical assay based on Hp-hemoglobin binding and utilizing SB-7 reagent in 12 dogs with spontaneous HAC before and after treatment with trilostane (30 or 60 mg PO q 12-24 h). Post-treatment Hp concentrations were measured at the time the owner reported an improvement in clinical signs. Pretreatment and post-treatment Hp values were compared with reference values and with values from 4 healthy control dogs. RESULTS: Two dogs with HAC had pretreatment Hp values within the reference interval; 10 dogs had moderate (n = 8) or marked (n = 2) increases in Hp concentration. After treatment with trilostane, Hp concentration remained within the reference interval (n = 2), decreased to within the reference interval (n = 3), or remained moderately increased (n = 7; 3-10 g/L). Overall, a significant decrease was observed in Hp concentration after trilostane treatment compared with pretreatment values (P <.005). Both untreated and treated dogs with HAC had significantly higher Hp concentrations (P <.001) when compared with control dogs. CONCLUSIONS: Clinical control of HAC did not closely relate to serum Hp concentration. Further studies are required to assess whether this is because of inadequate control of disease or because a build-up of cortisol precursors or secondary effects of HAC affect Hp concentration.     

An analysis of factors underlying hypotrichosis and alopecia in Irish Water Spaniels in the United Kingdom

A survey on the occurrence of dermatoses in the Irish Water spaniel (IWS) was carried out in the United Kingdom. A group of 20 dogs was selected and examined clinically. All dogs had a nonpruritic, noninflammatory, regionalized hair loss affecting the same areas of the body in males and females, although an initial cyclical pattern associated with the oestrus cycle was identified. Hormonal investigations showed features suggestive of an abnormality of steroidogenesis. Histopathology revealed features similar to canine recurrent flank alopecia (CRFA) and follicular dysplasia associated with abnormal melanization, as in colour dilution alopecia, although the clinical features did not correlate with those conditions. Dietary changes improved coat and skin quality in most of the cases in this series but the role of the diet was not investigated further. This study suggests that hair loss in IWS is influenced by dietary factors and sexual hormones. Abnormalities of the steroidogenic pathways may contribute to the severity of the condition.     

绵羊秃毛症的中药治疗及其鉴别

利用中草药对绵羊 (牧羊 )秃毛症进行综合治疗 ,收到满意的疗效     

犬脱毛综合征症状鉴别诊断

临床中常有犬脱毛的现象，引起脱毛症的疾病很多，常发的有遗传病、寄生虫病、真菌性皮肤病、内分泌疾病和营养代谢病，作者综述了各类疾病的临床症状特征，提供了犬脱毛症鉴别诊断的思路和方法，为该病的治疗提供了理论和实践依据。     

Mapping the canine skin: a study of coat relative humidity in Newfoundland dogs

Abstract An instrument is described which uses air aspirated via a narrow probe from an animal's hair coat to assess the relative humidity (RH) of air within the coat. This was used to investigate regional differences in coat humidity in a group of 21 Newfoundland dogs maintained in a constant environment of 40%RH. At sites over the rump, mid-lateral thigh and chest wall, the coat RH was about 50%, whilst beneath the tail and on the ventral neck the RH was about 70%. It was observed that at tail and neck sites the RH rose with increasing age of the subject. No differences were observed related to the coat colour or sex of the subjects, but coat type was relevant. The relative humidity of finer coats on exposed sites was about 7% lower than those of normal coats. The physical features affecting these findings, i.e. convection, conduction and the effect of matting, are discussed, together with the implications for microbial colonization. Résumé— Un instrument qui utilise à l'aide d'une sonde étroite l'air aspiréà partir du pleage pour mesurer l'humidité relative (HR) du pelage est décrit. Celui-ci a été employé pour déterminer les différences régionales de l'humidité relative dans un groupe de 21 Terre Neuves maintenus dans un environnement constant à 40% d'humidité relative. L'humidité relative est de 50% sur les membres, les faces internes des cuisses et le thorax, tandis que sous la queue et le cou, elle est de 70%. Il a été observéégalement qu'au niveau de la queue et du cou, l'humidité relative augmente avec l'âge. Aucune différence n'est notée en function de la couleur du pelage et le sexe des animaux. L'humidité relative des pelages plus fins des sites exposés est de 7% plus bas que celle des pelages normaux. Les facteurs physiques influant sur l'humidité relative tels que la convection, la conduction, l'effet du pansage sont discutés notamment avec leurs implications possibles dans la colonisation microbienne. [Chesney, C. J. Mapping the canine skin: a study of coat relative humidity in Newfoundland dogs (Cartographie de la peau du chien: étude de l'humidité relative du pelage des Terre Neuve). Veterinary Dermatology 1996; 7 : 35–41.] Resumen Se describe un instrumento que utiliza aire aspirado del pelo de un animal a través de una sonda para evaluar la humedad relativa (HR) del aire en el pelo. Ello se utilizó para investigar las diferencias regionales en humedad del pelo en un grupo de 21 perros Terranova mantenidos en un medio ambiente constante al 40% HR. En las zonas de grupa, muslo medial-lateral y pared torácica, la HR del pelo fue del 50%, mientras que bajo la cola y en cuello ventral fue del 70%. Se observó que la HR en la cola y cuello aumentaba con la edad del individuo. No se observaron diferencias por color del pelo o sexo, pero el tipo de pelo sí tenía importancia. La HR en pelo más fino en las zonas expuestas era un 7% menor que el de pelo normal. Se discuten los factores fisicos que afectan estas zonas, p.ej. convección, conducción y el efecto del enmarañamiento, junto con las implicaciones que ello tiene en la colonización bacteriana. [Chesney, C. J. Mapping the canine skin: a study of coat relative humidity in Newfoundland dogs (Mapeo de la piel canina: estudio de la humedad relativa del pelo en perros Terranova). Veterinary Dermatology 1996; 7 : 35–41.] Zusammenfassung— Es wird ein Gerät beschrieben, welches Luft verwendet, die mit einer schmalen Sonde aus dem Haarkleid des Tieres gewonnen wurde, um die relative Feuchtigkeit (RH) der Luft innerhalb des Fells auszuwerten. Dies wurde benützt, um regipnale Unterschiede in der Fellfeuchtigkeit bei einer Gruppe von 21 Neufundländern, die unter konstanten Umgebungsbedingungen von 40% RH gehalten wurden. An Stellen über dem Rumpf, mittel-lateralen Schenkel und der Brustwand betrug die Fell-RH um 50%, während sie unter dem Schwanz und am ventralen Hals 70% aufwies. Es wurde beobachtet, daß an der Schwanz- und Halsregion die RH mit zunehmendem Alter des Tieres zunahm. Es konnten keine Unterschiede bezüglich Fellfarbe oder Geschlecht der Tiere festgestellt werden, der Felltyp war jedoch relevant. Die relative Feuchtigkeit über feinerem Fell an exponierten Regionen war 7% niedriger als die über normalem Fell. Die physikalischen Vorgänge, die diese Befunde beeinflussen, z.B. Konvektion, Konduktion und die Wirkung des ‘Matting’ werden diskutiert zusammen mit den Beziehungen zur mikrobiellen Besiedelung. [Chesney, C. J. Mapping the canine skin: a study of coat relative humidity in Newfoundland dogs (Landkarte der Hundehaut: Studie über die Feuchtigkeit im zusammenhang mit dem Haarkleid beim Neufundländer). Veterinary Dermatology 1996; 7 : 35–41.]     

Medical management of pituitary-dependent hyperadrenocorticism: mitotane versus trilostane

Pituitary-dependent hyperadrenocorticism is a common endocrine disorder in dogs in the United States. Once a diagnosis is established, a decision must be made whether or not to pursue treatment, and if so, which medication to use. Historically, mitotane (Lysodren, o,p'-DDD, Bristol-Myers Squibb, New York) has been the most commonly used treatment for medical management. Its use is complicated and comes with many potential side effects, making many practitioners wary of its use. Recently, trilostane has been proven to be an effective treatment of pituitary-dependent hyperadrenocorticism and is approved for use in other countries. Treatment with trilostane is somewhat simpler and the incidence of side effects seems to be less when compared with mitotane therapy. Either treatment can be a safe and effective method of treatment for pituitary-dependent hyperadrenocorticism when the practitioner and client are well educated regarding their use and an appropriate monitoring protocol is used.     

Morphologic and immunologic characterization of a canine isthmus mural folliculitis resembling pseudopelade of humans

The clinical, histopathologic and immunopathologic features of a novel form of isthmus mural folliculitis in dogs, which resembles pseudopelade in humans, were characterized. Clinically, dogs exhibited variably distributed foci of alopecia that persisted without treatment or did not respond to immunosuppressive therapy. Histopathologically, mixed mononuclear cell infiltrates, largely lymphocytes, infiltrated the follicular isthmus. Occasionally, inflammation extended above and below the follicular isthmus but did not involve the hair bulb or the epidermis. Severe follicular atrophy and variable atrophy of sebaceous glands occurred in all dogs. Folliculotropic lymphocytes exhibited most commonly CD3 and CD8 (cytotoxic T cells). Autoantibodies specific for the lower hair follicle were detected in the serum of affected patients. Western immunoblotting demonstrated binding of these antibodies to multiple follicular keratinocyte proteins, including hair keratins and trichohyalin. Lack of hair regrowth (in contrast to canine alopecia areata), as well as location of inflammation and extreme atrophy of adnexal units are similar to findings seen in human pseudopelade.     

Review cutaneous lesions of the canine scrotum

Scrotal lesions are uncommon and often present a diagnostic challenge. In the veterinary literature there are no texts devoted to this subject. This study reviews and illustrates canine scrotal lesions following an aetiological layout with the aim of facilitating clinical identification and diagnosis. Infectious, immune-mediated, endocrinological and neoplastic conditions are the most commonly reported causes of scrotal lesions in the dog. They may affect the scrotum only or other parts of the body as well. The clinical presentation of the lesions, the presence of primary or secondary lesions and the presence of clinical signs of systemic disease may help in obtaining a diagnosis. In some cases further investigations are necessary to reach a definitive diagnosis. Histopathology aids in understanding pathological reactions of the scrotal skin but unfortunately this is not commonly carried out and few reports in the literature include histopathology. The list of conditions given in this review is not exhaustive and other, more rare, diseases may be encountered.     

Histopathologic features of canine distichiasis

Objective To describe the histologic features of canine distichiasis using excised tarsoconjunctival specimens that included roots of distichiatic cilia. Procedures The study group included 21 strips of cilia‐bearing tarsoconjunctiva resected from 20 dogs with distichiasis. Eyelid tissue specimens were also collected from 11 euthanized dogs without distichiasis to serve as controls. All flat mount preparations were processed for histologic examination, and serial sections were stained with hematoxylin‐eosin (H&E). A total of 157 slides were examined for the study group to describe the follicles and path of the distichiatic hairs and determine their potential connection with the tarsal glands. A total of 82 slides were examined for the control group. Results In 19 of the 20 dogs with distichiasis, serial sections of the specimens identified anatomic segments of hair follicles located abnormally in the eyelid tarsus and associated with the aberrant cilia. They appeared as hair bulbs adjacent to tarsal glands, middle portions of hair follicles located between sebaceous lobules, and single or multiple hair shafts present within the sebaceous duct. The tarsal glands in the cilia‐bearing tarsoconjunctiva were not different from those of the controls, in which no distichiatic hair bulbs or shafts were observed. Conclusions These results demonstrate that adventitious cilia are not associated with histologic changes of the tarsal glands, and appear to arise from ectopic hair follicles present in the tarsus. Canine distichiasis may result from anomalous regulation of morphogenesis of hair follicles in the mesenchymal tissue of the tarsal plate.     

A case of canine cutaneous clear cell adnexal carcinoma with prominent expression of smooth muscle actin

Cutaneous clear cell adnexal carcinoma was found in the right lip of a 14-year-old male castrated Shih Tzu. Histologically, the tumor mostly consisted of neoplastic cells with clear or vacuolated cytoplasms and contained frequent tubular structures. Neoplastic cells showed coexpression of pan-cytokeratin (CK) and vimentin by double-labeled immunofluorescence staining. In addition, immunohistochemistry revealed that the tumor cells were positive for pan-CK (AE1/AE3, KL1, CAM 5.2), CK-7, CK-8, CK-14, CK-15, CK-18, vimentin and alpha-smooth muscle actin (SMA) with varied intensity and positivity. Among these marker proteins, SMA was positive in 75% of the tumor cells. On the other hand, CK-15, which is a specific marker of follicular stem cells, was expressed in less than 1% of the tumor cells. Based on these findings, the tumor showed diverse differentiation in apocrine sweat glands and the inner and outer root sheaths of hair follicles, indicating the follicular stem cell to be the origin of this tumor.     

微量元素缺乏导致绵羊脱毛症的诊断和治疗

绵羊脱毛症通常具有一种或多种病因。通过对某羊场羊群进行流行病学调查以及临床症状初步诊断,发现有22只羊疑似发生脱毛症,再随机选择患有脱毛症的羊只共计10只,对血清中19种元素进行测定,被检血清中Zn、I含量均低于参考值,3只羊血清中Cu含量略低于参考值。根据初步诊断、寄生虫检测、血清常量及微量元素检测结果,确定该养殖场羊只脱毛症的发病原因主要为Zn、I、Cu缺乏,补充相应元素治疗2周后,22只脱毛症病羊全部治愈,治愈率100%。     

Alopecia and dermatopathy of the lower back following pelvic fractures in three cats

Abstract   An alopecia and dermatopathy following pelvic fractures associated with vehicular trauma is reported in three cats. The animals presented 3–4 weeks post injury with acute hair loss, glistening appearance of the skin and erosions involving the lower back. Histological examination revealed atrophy of the hair follicles and adnexal structures and follicular telogenization, dermal fibroplasia and mild lymphocytic infiltrate, fibroplasia and inflammation in the panniculus. Vascular damage secondary to the external trauma to blood vessels supplying the skin over the lumbar region and subsequent ischaemia may represent the pathomechanism of this type of alopecia. Focal permanent hair loss can be expected.     

Trachyonychia associated with alopecia areata in a Rhodesian Ridgeback

Trachyonychia associated with alopecia areata was diagnosed in an 8-year-old Rhodesian Ridgeback. Clinical and histological findings are described in this respectively unreported and rare condition in the dog.     

Treatment of canine mast cell tumours with prednisolone and radiotherapy

This retrospective study describes 35 dogs with non‐resectable, grade I–III mast cell tumours on the head or limb treated with prednisolone (40 mg m^?2 daily) for 10–14 days prior to radiotherapy (4 × 800 cGy fractions at 7‐day intervals) from a 4 MV linear accelerator. Prednisolone was continued at a reduced dose rate (20 mg m^?2) during radiotherapy and for 2 months or longer afterwards. Eighteen of 24 tumours (75%) decreased in size in response to prednisolone treatment. By 6–8 weeks following radiotherapy, 12 dogs had achieved a complete remission and 19 a partial response. Two tumours remained static and two progressed during the course of treatment. The overall response rate was 88.5%. With long‐term follow‐up, 11 dogs experienced local recurrence (n = 4), metastasis (n = 5) or both (n = 2). The median progression‐free interval was 1031 days (95% CI 277.44–1784.56, Kaplan–Meier), with 1‐ and 2‐year progression‐free rates of 60 and 52%, respectively. Tumour grade did not predict the prognosis for this group of dogs, but tumour location did affect the outcome. Dogs with tumours located on the limb survived longer than those with tumours on the head. The combination of prednisolone with radiotherapy appears to have a useful role in the management of measurable mast cell tumours sited on the head and distal extremities.     

Impaired local deiodination of thyroxine to triiodothyronine in dogs with symmetrical truncal alopecia

Thyroid dysfunction causes certain dermatological alterations in dogs. Insufficient delivery of thyroid hormone to the skin may originate not only from inadequate thyroid function but also from impaired local activation of thyroxine in the target organ. Thyroid parameters and deiodination were investigated in healthy dogs (group C) and in dogs with cutaneous lesions associated with hypothyroidism (group H) or with a low-T₃ syndrome (group LT). The ability of the skin to convert T₄ to T₃ was impaired in both groups H and LT but not in the controls. It is concluded that impaired local deiodination may contribute to skin problems in dogs.Abbreviations bwt body weight - DTT dithiothreitol - PBS phosphate-buffered saline (pH 7.5, 0.05 mol/L) - PTU propylthiouracyl - RIA radioimmunoassay - TRH thyrotropin-releasing hormone - TSH thyroid-stimulating hormone     

Vaccine-induced ischemic dermatopathy in the dog

Post-rabies vaccination alopecia associated with concurrent multifocal ischemic dermatopathy was identified in three unrelated dogs. All dogs received subcutaneous rabies vaccine dorsally between the scapulae several months prior to observation of the initial area of alopecia at the vaccination site. All three dogs developed multifocal cutaneous disease within 1–5 months after the appearance of the initial skin lesion. Cutaneous lesions were characterized clinically by variable alopecia, crusting, hyperpigmentation, erosions, and ulcers on the pinnal margins, periocular areas, skin overlying boney prominences, tip of the tail, and paw pads. Lingual erosions and ulcers were observed in two dogs. Histopathologic examination of the skin revealed moderate to severe follicular atrophy, hyalinization of collagen, vasculopathy, and cell-poor interface dermatitis and mural folliculitis. Hypovascularity was demonstrated by diminished Factor VIII staining of blood vessels. Nodular accumulations of lymphocytes, plasma cells, and histiocytes in the deep dermis and panniculus also were noted at the rabies vaccination site. An atrophic, ischemic myopathy paralleling the onset of skin disease was identified in two dogs. Histological examination of muscle biopsy specimens demonstrated perifascicular atrophy, perimysial fibrosis, and complement (C) _5b-9 (membrane attack complex) deposition in the microvasculature of both dogs with myopathy. Marked improvement of the skin disease was obtained with oral pentoxifylline and vitamin E.