Scaling dermatosis in three dogs associated with abnormal sebaceous gland differentiation.

BACKGROUND: Abnormal sebaceous gland differentiation, so-called 'sebaceous gland dysplasia', is a rare condition described in the dog and the cat. Although little is known about this condition, it is thought that a genetic defect causes abnormal sebaceous gland development. Clinically, this condition occurs in young cats and dogs and is characterized by variable degrees of adherent scale, hair casts, poor coat quality and hypotrichosis. HYPOTHESIS/OBJECTIVE: Here, we describe the clinical presentation and treatment of three adult dogs with abnormal sebaceous gland differentiation. ANIMALS: Three adult dogs presented with a keratinization defect characterized by progressive scaling, hair casts, dull, dry, brittle hair coat and hypotrichosis beginning in puppyhood to early adulthood. METHODS: Multiple 6 mm punch skin biopsy samples were obtained from each dog. Treatments included various topical keratomodulatory agents, oral essential fatty acids and oral vitamin A. RESULTS: Histologically, all sebaceous glands were small and composed of a mixture of irregularly clustered basal reserve cells and mature sebocytes. With therapy, two of the dogs showed moderate to marked clinical improvement in scaling, hair casts and hair coat quality. CONCLUSIONS AND CLINICAL IMPORTANCE: Although rare, 'sebaceous gland dysplasia' should be considered in cases where a primary keratinization defect is suspected. Given that abnormal sebaceous differentiation is a structural defect of the skin, treatment must be maintained and is aimed at ameliorating the clinical signs rather than curing the disease.

Genetic characterization of healthy and sebaceous adenitis affected Standard Poodles from the United States and the United Kingdom.

The degree of heterogeneity associated with geographic origin and sebaceous adenitis (SA) status in Standard Poodles from the United States (US) and the United Kingdom (UK) was assessed. Healthy and SA-affected Standard Poodles from the US and the UK shared a major mitochondrial DNA (mtDNA) haplotype and a single Y chromosome haplotype. However, minor mtDNA haplotypes and frequencies were somewhat different between US and UK dogs and were significantly less associated with SA than major haplotypes across both populations. The US and UK populations exhibited recent divergence from a common gene pool, based on allele frequencies of 24 highly polymorphic short tandem repeats and principle coordinates and cluster analyses of genotype frequencies. However, there was no differentiation between SA affected and unaffected dogs. Over 90% of US and UK Poodles shared a common dog leukocyte antigen (DLA) class II haplotype, but showed some differentiation in minor haplotype frequency. No difference was observed in haplotype heterozygosity between SA affected and unaffected dogs from the same country and no disease association for SA was found within the DLA region by a high density single nucleotide polymorphism (SNP) scan. Zygosity mapping in the DLA region of Poodles indicated much lower site-specific diversity than in an outbred population of street dogs from Bali, Indonesia, reflecting the degree that breed associated historical bottlenecks have reduced diversity in a polymorphic region of the genome. This study shows possible pitfalls in more extensive genome-wide association studies, such as case and control numbers, population stratification, the involvement of multiple genes, and/or the possibility that SA susceptibility is fixed or nearly fixed within the breed, which can reduce power to detect genetic associations.

Abnormal sebaceous gland differentiation in 10 kittens ('sebaceous gland dysplasia') associated with generalized hypotrichosis and scaling.

A rare congenital dermatosis, characterized by progressive hypotrichosis with variable scaling and crusting, occurred in 10 short-haired kittens in North America and Europe. Lesions appeared at between 4 and 12 weeks of age, commencing on the head and becoming generalized. The tail was spared in two kittens. Generalized scaling was mild to moderate, often with prominent follicular casts. Periocular, perioral, pinnal and ear canal crusting was occasionally severe. The skin was thick and wrinkled in two kittens. Histologically, the main lesion was abnormal sebaceous gland morphology. Instead of regular differentiation from basal cells to mature sebocytes, the glands were composed of a haphazard collection of undifferentiated basaloid cells, some partly vacuolated and a few containing eosinophilic globules. Mitotic figures and apoptotic cells were present in an irregularly thickened follicular isthmus. Lymphocytic mural folliculitis and mild sebaceous adenitis were rare. Orthokeratotic hyperkeratosis and follicular casts were present. Hair follicles were of normal density and were mostly in anagen, but some contained malacic hair shafts. Perforating folliculitis, leading to dermal trichogranuloma formation, occurred occasionally. Further biopsy samples taken at 2 years and at 3 and 4 years, respectively, from two kittens revealed similar but often more severe sebaceous gland lesions. Hair follicles were smaller, with many in telogen. The young age of onset suggests a genetic defect interfering with sebaceous and, possibly, follicular development. These lesions are discussed with reference to studies of mouse mutants in which genetic defects in sebaceous differentiation cause a similar phenotype of hyperkeratosis and progressive alopecia.

Sebaceous gland metaplasia in the oesophagus of a cynomolgus monkey (Macaca fascicularis).

Microscopical evaluation of tissues from a mature female cynomolgus monkey assigned to a 13-week oral toxicity study revealed nests of sebaceous cells within the mucosa of the distal oesophagus. The sebaceous cell nests showed normal differentiation from basally-oriented seboblasts to centrally-orientated mature sebocytes. No excretory ducts were found, but solitary or small groups of vacuolated sebocytes were present in the overlying normal, non-keratinized squamous epithelium. The finding of sebaceous cells, of presumed ectodermal origin, in the oesophageal mucosa, which is of endodermal origin, is of scientific interest. Different theories may explain the existence of this peculiarity, but sebaceous gland metaplasia is the most plausible. The mucosal change was thought to be unrelated to treatment and is the first case of sebaceous gland metaplasia reported in the oesophagus of a non-human primate.

Applied dermatology: sebaceous adenitis in dogs.

Sebaceous adenitis is an inflammatory skin disease of unknown etiology that leads to a poor haircoat. It occurs mostly in young adult to middle-aged dogs. Clinical signs vary in severity and distribution among breeds and types of haircoat. Lesions include alopecia, scaling, and follicular casts that are typically distributed over the face, head, pinnae, and trunk. Diagnosis is based on histopathologic findings of sebaceous gland inflammation and loss. Treatment for sebaceous adenitis involves lifelong management with various topical therapies containing keratolytic/keratoplastic agents, emollients, and humectants in addition to oral therapies such as omega-3/omega-6 fatty acids, cyclosporine, and/or retinoids.

Severe ulcerative and granulomatous pinnal lesions with granulomatous sebaceous adenitis in unrelated vizslas.

Granulomatous sebaceous adenitis (GSA) is uncommon in dogs; however, certain breed predilections exist. In this report, three cases of GSA in unrelated vizslas have been described. All cases initially presented with episodes of otitis externa followed by severe inner pinnal lesions. In one case, multifocal coalescing inner pinnal ulceration appeared 4 wk prior to the occurrence of the skin lesions. The other two cases presented with simultaneous pinnal and skin lesions following episodes of bilateral otitis. The pinnae were diffusely erythematous and had multiple coalescing erosions and ulcers. The body lesions consisted of multifocal alopecia, papules, and fine scales. Biopsies of the skin and pinnae confirmed GSA. Two dogs responded to treatment with synthetic retinoids and cyclosporin A, respectively. One dog was not treated, and the owners preferred euthanasia when the ear lesions recurred and did not respond to glucocorticoids. To the best of the authors' knowledge, GSA with multifocal coalescing ulcerative pinnal lesions has not previously been reported.

Oral vitamin A as an adjunct treatment for canine sebaceous adenitis.

Medical records of dogs with sebaceous adenitis diagnosed by histopathology over an 18-year period were reviewed. From a total of 40 cases, 24 were treated with oral vitamin A. Dogs ranged from 9 months to 12 years of age at the time of disease onset. Purebred as well as mixed-breed dogs were affected. Akitas represented approximately one-third of the affected population. No sex predilections were observed. Vitamin A was administered for a minimum of 1 month. Doses varied from 380 to 2667 IU/kg/day, with a mean of 1037 IU/kg/day. Two dogs received oral vitamin A exclusively. Concurrent treatments included systemic antibiotics, systemic antifungal medications, fatty acid supplementation and various topical treatments. Of 24 dogs treated with vitamin A, three were lost to follow-up. Twelve owners were satisfied with the overall appearance of their dogs, reporting ≥25% improvement in clinical signs, including level of pruritus, amount of scale, alopecia and overall coat quality, compared with pretreatment appearance. Three owners observed adequate initial improvement, with regression to pretreatment state within 6 months of starting treatment. Two owners reported 25-50% improvement in clinical signs while on oral vitamin A supplementation; however, changes were attributed to concurrent topical treatment. Six owners reported no improvement and discontinued oral administration of vitamin A within 7 months. No correlations could be made between vitamin A dosage and response to treatment; prognoses could not be made based on clinical and histopathological findings.

Sebaceous adenitis in Havanese dogs: a retrospective study of the clinical presentation and incidence.

Sebaceous adenitis is a suspected immune-mediated disease that targets and destroys sebaceous glands. This retrospective study evaluated the clinical presentation and incidence of sebaceous adenitis in Havanese dogs. Sebaceous adenitis was diagnosed in 35% (12 of 34) of Havanese dogs presented over a 5-year period. Onset of clinical signs occurred during young adulthood. Follicular casts were present in 92% (11 of 12) of affected dogs. Other common clinical signs included alopecia and hypotrichosis. The trunk, head and ears were commonly affected, with 67% (8 of 12) of cases having pinnal and/or external ear canal involvement. Secondary pyoderma was seen in 42% (5 of 12) of dogs. Histopathology revealed absent sebaceous glands in 83% (10 of 12) and a lymphoplasmacytic periadnexal infiltrate in 92% (11 of 12) of samples. Treatment included multiple modalities. Cyclosporin was prescribed in 83% (10 of 12) of cases. Other systemic therapies included vitamin A and fatty acid supplementation. Topical therapies included antiseborrhoeic shampoos and sprays, and oil soaks. Follow-up ranging from 2 months to 3 years was obtained in 67% (8 of 12) of dogs. Improvement ranged from minimal to marked, with better clinical response associated with longer duration of treatment. Owners with follow-up of more than 1 year commonly reported occasional flares of the clinical signs. This study found that sebaceous adenitis was a common diagnosis in Havanese dogs, that the ears were commonly affected and that a lymphoplasmacytic periadnexal infiltrate associated with absent sebaceous glands was frequently seen on dermatohistopathological examination.

A multicentre placebo-controlled clinical trial on the efficacy of oral ciclosporin A in the treatment of canine idiopathic sebaceous adenitis in comparison with conventional topical treatment.

Canine idiopathic sebaceous adenitis (ISA) is an inflammatory reaction of sebaceous glands, potentially resulting in their complete loss. It is considered a T-cell-mediated disease, but its precise pathogenesis is still unknown. Topical treatment with oil soaks, humectants and shampoos is effective but laborious. Ciclosporin A (CsA), an immunomodulatory drug, has recently been shown to ameliorate the clinical picture of ISA and to reduce inflammation greatly. It is, however, an expensive treatment option. The objective of this multicentre, partly double-blinded, randomized controlled study was to evaluate the efficacy of ciclosporin A, either alone or with topical therapy, in comparison to conventional topical treatment alone, as measured by the primary end-points alopecia and scaling, and multiple histopathological secondary objectives. Thirty-four dogs with an established diagnosis were treated for 4-6 months and were evaluated before, during and after therapy. Both CsA and topical therapy demonstrated efficacy in this study. Differences between the treatment protocols were marginal. Topical treatment, both alone and in combination with CsA, appeared to reduce scaling more effectively than CsA alone. Both therapies reduced alopecia. There is evidence of a synergistic benefit on both scaling and alopecia, if both treatment options are combined. Inflammation of the sebaceous glands is also best reduced by a combination of both CsA and topical therapy. There is evidence that regeneration of sebaceous glands is best achieved by CsA, either given alone or in combination with topical treatment.

Idiopathic generalized sebaceous gland hyperplasia of the Border terrier: a morphometric study.

Skin biopsies from five Border terriers with histologically confirmed idiopathic, generalized sebaceous gland hyperplasia (Group A) were compared morphometrically to those from four unaffected Border terriers (Group B) and the unaffected dogs to biopsies from four other terrier breeds (Group C). Dogs in Group A had significantly higher numbers of sebaceous gland lobules per hair follicle than those in Group B (P=0.020) but there was no significant difference between Groups B and C. The total sebaceous gland lobular area per hair follicle was significantly higher in dogs in Group A than Group B (P=0.020) but there were no differences between Groups B and C. There were no significant differences in the size of the individual sebaceous gland lobules. There were no significant differences in the total number of basal or mature sebocytes between Groups A and B but significantly lower numbers of both cell types were seen in Group C compared to Group B. There were significantly more basal sebaceous cells undergoing mitosis in dogs in Group A than Group B (P=0.017) but no significant difference between Groups B and C. These results indicate that the physical signs of sebaceous gland hyperplasia are caused by an increase in the number of sebaceous gland lobules and total lobular area. Border terriers may be genetically predisposed to the development of idiopathic generalized sebaceous gland hyperplasia compared with other dog breeds but also to sebaceous gland hyperplasia secondary to other dermatopathies.

Histopathological differences between canine idiopathic sebaceous adenitis and canine leishmaniosis with sebaceous adenitis.

Sebaceous adenitis (SA) may be idiopathic (ISA) or associated with other disorders. The purpose of the present study was to compare the cutaneous histopathology of SA in cases in which Leishmania organisms were detected by immunohistochemistry (IHC) with that of cases diagnosed as ISA. Skin sections of 29 patients were evaluated histologically and divided into two groups, one characterized by several epidermal and subepidermal lesions, a granulomatous to pyogranulomatous nodular to diffuse dermatitis involving the sebaceous glands and a positive IHC for Leishmania spp. The other group was characterized by orthokeratotic hyperkeratosis, follicular keratosis with different degrees of pyogranulomatous to granulomatous SA, lack of nodular dermatitis and a negative IHC for Leishmania spp. Hidradenitis was present in both groups. From these results it can be concluded that SA in canine Leishmaniosis (CL) is usually present together with a nodular to diffuse dermal infiltrate and epidermal and subepidermal lesions, and that SA in the absence of dermal inflammation is probably not associated with or suggestive of CL, even in regions where the disease is endemic.

Sebaceous adenitis in Swedish dogs, a retrospective study of 104 cases.

BACKGROUND: Sebaceous adenitis (SA) is an uncommon, immune mediated skin disease in dogs. The aim was to retrospectively investigate SA in dogs in Sweden with respect to breed, sex and age distribution. A second aim was to retrospectively compare clinical signs in dogs with generalized SA and to estimate the survival after diagnosis in the English springer spaniel, standard poodle and the akita. METHODS: In total 34 Swedish veterinarians contributed with 104 clinically and histologically verified SA cases. Breed, gender and age at diagnosis were registered for each case. The degree of clinical signs at time for diagnosis and at follow-up and information about treatments, concurrent diseases and euthanasia were recorded for the springer spaniels, standard poodles and akitas using a standardized questionnaire. RESULTS: A total of 104 cases of SA were included; most cases were recorded for the springer spaniel (n = 25), standard poodle (n = 21) and the akita (n = 10). These three breeds, together with the lhasa apso and the chow-chow, were the most common when national registry data from the Swedish Board of Agriculture and Swedish Kennel Club were considered. The mean age at diagnosis was 4.8 years. The proportion of males was 61%. When the springer spaniels, standard poodles and the akitas with generalized signs were compared (n = 51), the spaniels showed significantly more severe clinical signs than the poodles at diagnosis regarding alopecia, seborrhoea, pyoderma and the overall severity of clinical signs. At follow-up, the degree of clinical signs for otitis externa and pyoderma differed significantly between the breeds. The estimated median survival time was 42 months. In dogs where data regarding survival was available at the end of the study (n = 44), SA was reported to be the reason for euthanasia in 14 dogs, whereof 7 within 24 months after diagnosis. CONCLUSION: The result of this study implicates that the English springer spaniel is a breed predisposed to SA and that it has more severe clinical signs than the standard poodle. A large proportion of the dogs (spaniel, poodle and akita) investigated regarding survival were reported to have been euthanized to great extent due to the disease.

Sebaceous adenitis in a 7-year-old Arabian gelding.

A 7-year-old Arabian gelding was presented with a 9-month history of progressive patches of nonpruritic scaling, crusting, alopecia, and leukoderma of the periocular areas and muzzle, becoming generalized over time. Sebaceous adenitis was diagnosed on histopathologic examination. Lesions resolved without treatment, coinciding with regression of a sarcoid on the neck.

Sebaceous adenitis in the Akita: clinical observations, histopathology and heredity.

Ninety-seven pure-bred Akitas were examined clinically and histologically for sebaceous adenitis. The diagnosis was established histologically in 23 Akitas by demonstrating an inflammatory reaction targeted against the sebaceous glands or a reduction in the number of glands. The clinical course of sebaceous adenitis in the Akita was similar to that seen in other breeds. The first skin lesions occurred mainly on the dorsal midline and ears. Compared with the Poodle, the age at first onset of the disease was more variable and the hair loss affected mainly the undercoat. The progression of sebaceous gland destruction varied between dogs and was not seen in all cases. Because bud-like sebaceous gland proliferation could be identified, it seems that regeneration of the sebaceous glands may occur. An autosomal recessive inheritance appears to be possible. Apart from a genetic background, immune-mediated factors possibly influence the onset and course of sebaceous adenitis.