Equine Skin Disease Research Articles

Onchocerca cervicalis: an underestimated cause of equine skin disease?

Onchocerca cervicalis: an underestimated cause of equine skin disease?

Sarcoid Associated with Infection by Habronema spp. in Equines in Brazil

Background: Equine sarcoid, supposed to be caused by infection with bovine papillomavirus type 1 or 2, is usually observedin previously traumatized skin areas, including lesions of habronemosis due to inoculation of third stage larvae in ulcerated wounds by Musca domestica or Stomoxys calcitrans. Little is known about the occurrence of diseases associated with equine sarcoid, mainly because limitations on clinical diagnosis, due to the different skin diseases that have to beconsidered as differential diagnoses. This report aimed to describe three cases of equine sarcoid associated with habronemosis in horses in the semiarid region of Northeastern Brazil.Cases: Three cases of sarcoid associated with habronemosis in equines were diagnosed at the Animal Pathology Laboratory of the Veterinary Hospital of the Federal University of Campina Grande, Patos, Paraíba. Case 1. A 5-year-old female showed in the ventral branch of the mandible a nodule of 3 cm in diameter, partially covered with skin and hair intercepted by areas of irregular surface with yellow-red ulcerations. The cut surface was formed by whitish and firm tissue. Case 2. It was a biopsy from a 4-year-old mare, who was not informed of the macroscopic characteristics of the lesion. Case 3. A 5-year-old horse presenting a nodular mass in the region of the tarsal-metatarsal joint, measuring 8.0x5.0x3.0 cm with an irregular, ulcerated, red-blackish surface. The cut surface was firm and whitish with brownish punctate areas. Microscopicallyall the lesions were classified as equine sarcoid of mixed type with abundant collagen fibers and randomly extensive proliferation of fibroblasts in the dermis. These fibroblasts had an elongated and weakly eosinophilic cytoplasm, rounded nucleus and prominent nucleoli. There were low mitotic activity. Hyperplasia, hyperkeratosis and sometimes ulcerated areas covered by serous cellular scabs were observed in the skin. Multifocal coalescing, granulomatous and eosinophilic lesions were observed within the neoplastic tissue. Cylindrical structures with an elongated thick eosinophilic outer cuticle and obvious side spicules, morphologically compatible with larvae Habronema spp, surrounded by inflammatory cells and cellular debris were observed in Cases 1 and 2. In case 3, intralesional larvae were not observed, but histologic lesions had a similar pattern than cases 1 and 2.Discussion: In these cases the affected animals presented simultaneously a mixed lesion of sarcoid and habronemosis, which leads to complications in clinical diagnosis and difficulties to institute appropriate therapy. Histopathological examination of such lesions is necessary because should characterize their morphology and the causative agent, discarding the other differential diagnoses. The combination of these two conditions can probably be related to the fact that sarcoid may develop up in places previously traumatized, such us lesions of habronemosis. It is important to differentiate these lesions from other skin diseases such as granulation tissue, pythiosis, squamous cell carcinoma and fibroid. Though the occurrence of sarcoid and simultaneous habronemosis in horses is rare in equine medicine, clinicians and pathologists who work with diagnosis may sporadically encounter similar cases, hence the importance of histopathologic analysis of skin samples, as this may help definition of the a etiology and also the institution of therapeutic measures and prognosis of affected animals.Keywords: equine skin disease, skin neoplasms, parasitic infection.

Establishment of primary keratinocyte culture from horse tissue biopsates

Primary cell lines established from skin tissue can be used in immunological, proteomic and genomic studies as in vitro skin models. The goal of our study was to establish a primary keratinocyte cell culture from tissue biopsates of two horses. The primary keratinocyte cell culture was obtained by mechanical and enzymatic dissociation and with explant culture method. The result was a heterogeneous primary culture comprised of keratinocytes and fibroblasts. To distinguish epithelial and mesenchymal cells immunofluorescent characterisation was performed, using antibodies against cytokeratin 14 and vimentin. We successfully at attained a primary cell line of keratinocytes, which could potentially be used to study equine skin diseases, as an animal model for human diseases, and for cosmetic and therapeutic product testing.

Equine dermatopathies in southern Brazil: a study of 710 cases

A retrospective study of equine skin diseases diagnosed in the Laboratório Regional de Diagnóstico, Faculdade de Veterinária, Universidade Federal de Pelotas was conducted between 1978 and 2013. The necropsy and biopsy protocols for horses received for diagnosis were reviewed to determine the prevalence of dermatopathies in southern Brazil. The most prevalent skin diseases in decreasing order were: sarcoid [234/710 (32.9%)], exuberant granulation tissue [81/710 (11.4%)], pythiosis [67/710 (9.4%)], squamous cell carcinoma [55/710 (7.7%)], papillomatosis [33/710 (4.6%)] and habronemiasis [30/710 (4.2%)]. Other skin lesions accounted for 25.3% of all cases studied. The Crioulo breed was the most prevalent [310/710 (43.6%)]. Horses aged between 2-5 years old [230/710 (32.3%)] were the most frequently affected. The data obtained in this study demonstrate the importance of skin diseases that affect horses in southern Brazil. The most of the dermatopathies observed in horses, although not resulting in death could cause aesthetic damage resulting in animal rejection, the inability to participate in collective sports activities and economic losses due to treatment and surgery costs

MycobacteriumDNA detection in liver and skin of a horse with generalized sarcoidosis

Sarcoidosis is a rare equine skin disease characterized primarily by an exfoliative and granulomatous dermatitis but also presenting granulomatous inflammation of multiple systems. The current report presents the clinical and histopathological findings of sarcoidosis in a 16-year-old American Quarter Horse gelding with nested polymerase chain reaction Mycobacterium spp. DNA detection within hepatic and skin samples. Mycobacterium spp. may play a role in the pathogenesis of equine sarcoidosis as has been proposed for human sarcoidosis.

Equine Bacterial and Fungal Diseases: A Diagnostic and Therapeutic Update

Bacterial and fungal skin diseases are important in the horse. Bacterial skin diseases (pyoderma) are most often caused by Staphylococcus species, Corynebacterium pseudotuberculosis or Dermatophilus congolensis . The most common clinical signs associated with bacterial skin infections are crusts, papules, abscesses, and draining tracts; the latter two lesions are more commonly associated with C. pseudotuberculosis . Ideally, antibiotic treatment should be based on bacterial culture and sensitivity. Fungal infections are most commonly caused by dermatophytes (“ringworm”) or Sporothrix schenkii , although the role of Malassezia in equine skin disease is beginning to be investigated. The clinical signs of fungal infections are variable and may include alopecia, crusts, papules, pruritus, nodules, ulcers, and draining tracts. The latter three lesions are more commonly associated with S. schenkii infection. Treatment is dependent on the organism cultured and may include both topical and/or systemic treatment.

Treatment of skin disease in the horse

TOPICAL therapy in small animals is an area that has received much attention over the past decade. There is a large range of topical dermatological products available to treat both...

Diagnostic procedures in equine skin disease

Diagnostic procedures in equine skin disease

Scratching at the surface of equine skin disease

Scratching at the surface of equine skin disease

Update on Four Unusual Equine Dermatoses

This article discusses some new thoughts on the pathogenesis of four unusual equine dermatoses: reticulated leukotrichia, hyper-esthetic leukotrichia, mane and tail dystrophy, and linear alopecia of the Quarter Horse. Although many of the thoughts contained herein are speculative, it is hoped that they stimulate discussion among those of us interested in the wonderful world of equine dermatology. More importantly, it is hoped that they stimulate further investigation and research. These diseases represent only the tip of the iceberg pf what we don't know about equine skin diseases!

An Overview of Equine Dermatoses Characterized by Scaling and Crusting

Scaling and/or crusting are common clinical findings associated with equine skin diseases. Scaling and crusting may be associated with pruritic or nonpruritic dermatoses. This article focuses on those conditions that are usually nonpruritic in horses. They include the infectious dermatoses, the keratinization/seborrheic disorders, photosensitization, and the immunologic/inflammatory disorders, including pemphigus foliaceus, equine exfoliative eosinophilic dermatitis and stomatitis, and equine histiocytic dermatitis (sarcoidosis). Clinical signs that help differentiate the various disorders are given, and diagnostic and therapeutic options are discussed.

A reassessment of sympathetic blocks as long term therapeutic modality for “RSD”

This article discusses some new thoughts on the pathogenesis of four unusual equine dermatoses: reticulated leukotrichia, hyperesthetic leukotrichia, mane and tail dystrophy, and linear alopecia of the Quarter Horse. Although many of the thoughts contained herein are speculative, it is hoped that they stimulate discussion among those of us interested in the wonderful world of equine dermatology. More importantly, it is hoped that they stimulate further investigation and research. These diseases represent only the tip of the iceberg of what we don’t know about equine skin diseases!