Colour Dilution Alopecia in Doberman Pinschers with Blue or Fawn Coat Colours: A Study on the Incidence and Histopathology of this Disorder

Abstract— A population of 57 blue or fawn Doberman Pinschers was studied to determine the incidence of colour dilution alopecia in this breed. Forty two dogs had hair loss, typical of colour dilution alopecia. The diagnosis was confirmed in 11 dogs by skin biopsy and in 6 dogs by light microscopic examination of plucked hairs. Key diagnostic features included large macromelanosomes in the hair shafts, free clumps of melanin in the lumens of hair follicles, and numerous perifollicular melanophages. An hypothesis on the pathogenesis of colour dilution alopecia is proposed. Résumé— Une population de 57 Pinschers à robe bleue ou feu a étéétudiée pour déterminer la fréquence de l'alopécie par dilution de couleur dans cette race. 42 chiens ont présenté une perte de poils caractéristique de l'alopécie par dilution de couleur. Le diagnostic a été confirmé chez 11 chiens par biopsie cutanée et chez 6 chiens par l'examen au microscope optique des poils épilés. Les caractéristiques diagnostiques comprennent la présence de grands macromélanosomes dans les racines des poils, de manchons libres de mélanine dans la lumière des follicules pileux et de nombreux mélanophages périfolliculaires. Une hyhpothèse sur la pathogénie de l'alopécie par dilution de couleur est proposée. Zusammenfassung— Untersucht wurden 57 blaue und rehfarbene Dobermänner, um das Vorkommen der Farbmutanten-Alopezie bei dieser Rasse feststellen zu können. 42 dieser Hunde zeigten den für diese Erkrankung typischen Haarausfall. Bei 11 Patienten wurde die Diagnose durch Hautbiopsie und bei 6 durch lichtmikroskopische Untersuchung von ausgezupften Haaren gesichert. Die charakteristichen Bilder waren Makromelanosome in den Haarschäften, freies zusammengeballtes Melanin im Lumen der Haarfollikel und zahlreiche perifollikuläre Melanophagen. Eine Hypothese für die Pathogenese dieser Erkrankung wird aufgestellt. Resumen Se estudió una población de 57 perros de raza Doberman y color gris o azul para determinar la incidencia de la alopecia por dilución de color en esta raza. 42 perros presentaban pérdidas de pelo típicas de la alopecia por dilución de color. En 11 perros el diagnóstico se confirmó mediante biopsia y en 6 mediante examen microscópico del pelo. Las características diagnósticas de este proceso consistían en la presencia de macromelanosomas en las vainas de los pelos, y en la presencia de acúmulos de melanina libre en el interior de los folículos pilosos y de melanófagos perifoliculares. Se propone una hipótesis sobre la patogenia de esta enfermedad.     

Studies on the Pathogenesis of Shimao Zheng (Fleece-eating) in Sheep and Goats

Research on the disease called shimao zheng, which had resulted in widespread fleece-eating and shedding by sheep and goats in the Haizi area of Akesa County of Gansu Province of China, was carried out by both laboratory studies and pathological observations. There was a marked deficiency of sulfur in the wool and tissues of the affected animals. The pathological changes were mainly loss of fleece, exposure of the skin, keratinization of the epidermal cells, narrowing and reduced numbers of the fleece follicles, and fewer sebaceous glands and sweat glands. Histologically, there was atrophy of the striated and cardiac muscles and of the epithelium of the convoluted tubules of the kidney, together with a glomerulonephritis. The disease was considered to be a local nutritional and metabolic disorder, probably mainly caused by sulfur deficiency.     

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     

Quantitative study of 'flame follicles' in skin sections of Shar-pei dogs

This study determined the frequency of occurrence and the mean number of 'flame follicles' per skin section and assessed their diagnostic significance in cutaneous biopsies of Shar-pei dogs. The number of 'flame follicles' per section was recorded in skin sections from 42 Shar-pei dogs, of which 40 had non-neoplastic skin disease and non-atrophic dermatoses and 2 had healthy skin. Forty-two skin sections from dogs of different breeds served as control specimens, 28 of which were examples of non-neoplastic and non-atrophic dermatoses and 14 were from dogs with healthy skin. Differences among groups were analysed by means of the unpaired Student's t-test. It was concluded that 'flame follicles' were more frequent and found in significantly higher numbers in the Shar-pei group when compared with the control group suggesting that 'flame follicles' in skin sections from Shar-pei dogs do not have the same diagnostic significance as in other breeds.     

Bald thigh syndrome of Greyhound dogs: gross and microscopic findings

Bald thigh syndrome (BTS) is a disease limited to Greyhound dogs. It is characterized clinically and grossly by bilateral hair loss on the lateral and caudal thighs. The cause of BTS is unknown but may be associated with hypothyroidism or hyperadrenocorticism. Samples of skin, thyroid glands, and adrenal glands from 43 Greyhound dogs with BTS were examined microscopically. Microscopic changes were characterized by dilatation of follicular infundibula, presence of catagen follicles and epidermal hyperplasia. Changes in the skin from these Greyhound dogs suggest an endocrinopathy as the cause; however, we were unable to confirm which one.     

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.     

Studies on ‘zinc deficiency syndrome’ in Black Bengal goats (Capra hircus) fed with fodder (Andropogon gayanus) grown on soil treated with an excess of calcium and phosphorus fertilizer

Overliming and excessive application of superphosphate caused a zinc deficiency in the soil and so reduced the uptake of zinc by fodder plants. Bucks reared on such fodder had significantly (p<0.01) less zinc in their hair compared with controls and suffered from conditioned zinc deficiency syndrome with a significant (p<0.01) loss of body weight, stunted growth, alopecia, lethargy, abnormal (kyphotic) gait, anorexia, digestive and respiratory problems. Oral supplementation with zinc sulphate very rapidly improved these conditions to near normality. Histological examination of samples of skin and testis from the zinc-deficient bucks revealed formation of excessive keratin, retention of nuclei in the stratum corneum and reduction in the width of the stratum granulosum in the skin, while samples of testis indicated degenerative changes, including atrophy of the seminiferous tubules, hyperplasia of the germinal epithelium and thickening of the walls of blood ve ssels.     

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%。     

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.     

鄂尔多斯地区山羊脱毛症病因分析

为了找出内蒙古鄂尔多斯地区山羊脱毛症发生的主要原因,对发病地区羊脱毛症进行了详细的流行病学调查,对发病地区病区土壤、饲草料和山羊体内部分矿物质元素和生化指标进行了检测与分析,结果表明:病羊脱毛处皮肤的实验室病原体检测未分离出寄生虫和皮肤真菌。发病地区处于低S、低Cu、低Zn、低Se的生态环境,而Mg、Mn处于正常水平。该病的发生与矿物质元素的代谢紊乱有很大关系。其中土壤、饲草料和山羊体内矿物质元素铜、锌、硒缺乏是该地区羊脱毛症发生的主要原因。