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Topic:Skin
The skin of horses is a complex organ that serves multiple functions, including protection, thermoregulation, and sensory perception. It consists of several layers, primarily the epidermis and dermis, each contributing to the overall health and functionality of the skin. The epidermis provides a barrier against environmental factors, while the dermis supports the skin structure and houses blood vessels, nerves, and hair follicles. Equine skin is also involved in the production of sweat and sebum, which aid in temperature regulation and skin lubrication, respectively. This page compiles peer-reviewed research studies and scholarly articles that explore the anatomy, physiology, and health conditions of equine skin, as well as advancements in dermatological treatments and care practices.
Pollen Allergies in Humans and their Dogs, Cats and Horses: Differences and Similarities. Both humans and their most important domestic animals harbor IgE and a similar IgE receptor repertoire and expression pattern. The same cell types are also involved in the triggering or regulation of allergies, such as mast cells, eosinophils or T-regulatory cells. Translational clinical studies in domestic animals could therefore help cure animal allergies and at the same time gather knowledge relevant to human patients. Dogs, cats and horses may spontaneously and to different extents develop immediate type symptoms to pollen allergens. The skin, nasal and bronchial reactions, as well as chro...
First report of junctional epidermolysis bullosa (JEB) in the Italian draft horse. Epitheliogenesis imperfecta in horses was first recognized at the beginning of the 20th century when it was proposed that the disease could have a genetic cause and an autosomal recessive inheritance pattern. Electron microscopy studies confirmed that the lesions were characterized by a defect in the lamina propria and the disease was therefore reclassified as epidermolysis bullosa. Molecular studies targeted two mutations affecting genes involved in dermal-epidermal junction: an insertion in LAMC2 in Belgians and other draft breeds and one large deletion in LAMA3 in American Saddlebred. Metho...
Skin malformations in a neonatal foal tested homozygous positive for Warmblood Fragile Foal Syndrome. Skin malformations that resembled manifestations of Ehlers-Danlos-Syndrome were described in a variety of domestic animals during the last century as cutis hyperelastica, hyperelastosis cutis, dermatosparaxis, dermal/collagen dysplasia, dermal/cutaneous asthenia or Ehlers-Danlos-like syndrome/s. In 2007, the mutation responsible for Hereditary Equine Regional Dermal Asthenia (HERDA) in Quarter Horses was discovered. Several case reports are available for similar malformations in other breeds than Quarter Horses (Draught Horses, Arabians, and Thoroughbreds) including four case reports for Warmb...
Osteopontin expression in healing wounds of horses and in human keloids. Convincing evidence shows that persistent or excessive expression of osteopontin (OPN) is linked to fibroproliferation of various organs in laboratory animals and in man, such that its downregulation is a logical therapeutic objective. Objective: To investigate OPN expression in an equine model of wound healing and in clinical specimens of equine exuberant granulation tissue and human keloids in an effort to better understand the contribution of this protein to inflammation-associated skin fibrosis. Methods: Description of gene and protein expression in an experimental equine model of wound he...
Constitutive activation of the ERK pathway in melanoma and skin melanocytes in Grey horses. Constitutive activation of the ERK pathway, occurring in the vast majority of melanocytic neoplasms, has a pivotal role in melanoma development. Different mechanisms underlie this activation in different tumour settings. The Grey phenotype in horses, caused by a 4.6 kb duplication in intron 6 of Syntaxin 17 (STX17), is associated with a very high incidence of cutaneous melanoma, but the molecular mechanism behind the melanomagenesis remains unknown. Here, we investigated the involvement of the ERK pathway in melanoma development in Grey horses. Methods: Grey horse melanoma tumours, cell lines ...
Sphere-forming capacity as an enrichment strategy for epithelial-like stem cells from equine skin. Mammal skin plays a pivotal role in several life preserving processes and extensive damage may therefore be life threatening. Physiological skin regeneration is achieved through ongoing somatic stem cell differentiation within the epidermis and the hair follicle. However, in severe pathological cases, such as burn wounds, chronic wounds, and ulcers, the endogenous repair mechanisms might be insufficient. For this reason, exogenous purification and multiplication of epithelial-like stem/progenitor cells (EpSCs) might be useful in the treatment of these skin diseases. However, only few reports a...
Equine sarcoid: In situ demonstration of matrix metalloproteinase expression. Sarcoids are the most prevalent equine skin tumours and remain a therapeutic challenge due to their differing clinical morphology, local aggressive behaviour, and high recurrence following surgical treatment. In vitro, sarcoid derived fibroblasts are invasive and express matrix metalloproteinase (MMP) -1, -2 and -9. It was hypothesised that the MMPs produced by neoplastic cells play a role in both their local invasiveness and interaction with the overlying epidermis (picket fence formation). The objective of this morphological study was to investigate the local behaviour and in situ MMP expres...
Monitoring changes in skin temperature associated with exercise in horses on a water treadmill by use of infrared thermography. Infrared thermography (IRT) was used to assess surface temperature change as an indirect measure of muscle activity and exercise associated changes in blood flow in the working hind limb muscles of horses (n=7) undergoing water treadmill exercise. Three treatments were investigated including the treadmill ran dry (TD), water at the height of the proximal interphalangeal joint (PIP) and water at the height of the carpus (CP). Maximum skin surface temperature was recorded from the region of the semitendinosus muscle during exercise at each water height. There was a significant difference in surf...
Development and characterization of an equine skin-equivalent model. There is increasing interest in the biological and pathological study of equine skin owing to the high prevalence of cutaneous diseases in horses. However, knowledge of equine skin cell biology and cultures is limited by the low number of in vitro studies in the literature. Objective: The objective of the study was to develop and characterize an in vitro equine skin equivalent. Methods: Cultures of pure equine keratinocytes and dermal fibroblasts were obtained by enzymatic digestion of skin biopsies. Fibroblasts were embedded into type I collagen matrices to obtain dermal scaffolds, the surfac...
Assessment of serum levels of allergen-specific immunoglobulin E in different seasons and breeds in healthy horses. The present study was designed to asses specific IgE towards environment allergens in 42 healthy horses. Determination of this immunoglobulin in serum serve as diagnostic tools in allergic diseases to improve efficacy of the treatment and proper allergen selection to specific immunotherapy. Serum levels of allergen specific IgE were measured with equine monoclonal antibody, using 15 individual and 5 mix allergens in North European Panel. The study revealed season dependent increased levels of allergen specific IgE in normal horses. It is noteworthy that healthy horses show high percentage of p...
First case report of ultrastructural cutaneous abnormalities in equine atopic dermatitis. Atopic dermatitis (AD) is a common skin disease that affects humans and animals. Skin impairment has been described in human and canine AD. Equine AD is recognized in practice but little is known about its pathogenesis. As remarkable similarities exist across species in terms of cutaneous manifestations of AD, it was speculated that skin abnormalities may also exist in atopic horses. This case report describes the ultrastructure of the stratum corneum of two normal and two atopic horses. Biopsies were taken from sites predisposed to AD and examined using electron microscopy. Stratum corneum in...
Characterization of IgE-mediated cutaneous immediate and late-phase reactions in nonallergic horses. To characterize the response of skin of nonallergic horses following ID injection of polyclonal rabbit anti-canine IgE (anti-IgE) and rabbit IgG. Methods: 6 healthy horses. Methods: Skin in the cervical area was injected ID with anti-IgE and IgG. Wheal measurements and skin biopsy specimens were obtained before and 20 minutes and 6, 24, and 48 hours after injection. Tissue sections were evaluated for inflammatory cells at 4 dermal depths. Immunohistochemical analysis for CD3, CD4, and CD8 was performed, and cell counts were evaluated. Results: Anti-IgE wheals were significantly larger than IgG...
Dermatological and morphological findings in quarter horses with hereditary equine regional dermal asthenia. Hereditary equine regional dermal asthenia (HERDA) is an autosomal recessive disorder affecting quarter horses (QHs); affected horses exhibit characteristic skin abnormalities related to abnormal collagen biosynthesis. Objective: To characterize the thickness and morphological abnormalities of the skin of HERDA-affected horses and to determine the interobserver agreement and the diagnostic accuracy of histopathological examination of skin biopsies from horses with HERDA. Methods: Six affected QHs, confirmed by DNA testing, from a research herd and five unaffected QHs from a stud farm. Methods:...
The effects of chemical and physical penetration enhancers on the percutaneous permeation of lidocaine through equine skin. The effect of physical and chemical permeation enhancers on in vitro transdermal permeation of lidocaine was investigated in the horse.Therefore, the effect of six vehicles (phosphate-buffered saline (PBS), 50% ethanol, 50% propylene glycol, 50% isopropylalcohol, 50% isopropylalcohol/isopropylmyristate and 50% dimethylsulfoxide) was examined as well as the effect of microneedle pretreatment with different needle lengths on transdermal drug delivery of lidocaine.The skin was obtained from the thorax of six Warmblood horses and was stored up to two weeks at - 20°C. Franz-type diffusion cells we...
Does a magnetic blanket induce changes in muscular blood flow, skin temperature and muscular tension in horses? Static magnetic blankets are often claimed to induce increases in blood flow, reduce muscle tension and tenderness, and be beneficial in both prevention and treatment of musculoskeletal injuries in horses. However, there are no studies that confirm alleged beneficial effects of magnets on muscles of the back in healthy horses. Objective: To investigate whether static magnets sewn into a blanket affect back muscle blood flow, skin temperature, mechanical nociceptive threshold (MNT) and behaviour in healthy horses. Methods: Prospective, randomised, blinded, placebo-controlled crossover study. Me...
Effect of a bandage or tendon boot on skin temperature of the metacarpus at rest and after exercise in horses. To determine the skin temperature of the metacarpus in horses associated with the use of bandages and tendon boots, compared with the bare limb, at rest and after 20 minutes of lunging. Methods: 10 adult horses. Methods: Skin temperature on the bare metacarpus of both forelimbs was measured at rest and after lunging. Subsequently, a bandage was applied to the left metacarpus and a tendon boot to the right metacarpus and skin temperature was measured at rest and after lunging. Skin temperature was measured with fixed sensors and thermographically. Results: Mean ± SD skin temperatures of the ba...
Genetic parameters for chronic progressive lymphedema in Belgian Draught Horses. Genetic parameters for chronic progressive lymphedema (CPL)-associated traits in Belgian Draught Horses were estimated, using a multitrait animal model. Clinical scores of CPL in the four limbs/horse (CPLclin ), skinfold thickness and hair samples (hair diameter) were studied. Due to CPLclin uncertainty in younger horses (progressive CPL character), a restricted data set (D_3+) was formed, excluding records from horses under 3 years from the complete data set (D_full). Age, gender, coat colour and limb hair pigmentation were included as fixed, permanent environment and date of recording as ra...
Equine epidermis: a source of epithelial-like stem/progenitor cells with in vitro and in vivo regenerative capacities. Besides the presence of somatic stem cells in hair follicles and dermis, the epidermis also contains a subpopulation of stem cells, reflecting its high regenerative capacity. However, only limited information concerning epidermis-derived epithelial-like stem/progenitor cells (EpSCs) is available to date. Nonetheless, this stem cell type could prove itself useful in skin reconstitution after injury. After harvesting from equine epidermis, the purified cells were characterized as EpSCs by means of positive expression for CD29, CD44, CD49f, CD90, Casein Kinase 2β, p63, and Ki67, low expression f...
Prevalence of cutaneous pathological conditions and factors associated with the presence of skin wounds in working equids in tropical regions of Veracruz, Mexico. A wide spectrum of welfare issues is encountered on working equids. The objectives of this study were: (i) to determine the prevalence of cutaneous lesions in working equids in tropical regions of the North-Central of Veracruz State, Mexico, (ii) to identify the most prevalent cutaneous pathological conditions in this population of working equids, and (iii) to identify risk factors associated to the presence of work-related skin wounds. A number of 467 working equids presented for treatment at Donkey Sanctuary Mobile Clinic Program - National Autonomous University of Mexico from seven differen...
Cutaneous leishmaniosis in a horse from northern Portugal. The first case of cutaneous leishmaniosis in a horse from the north of Portugal, with a 1.5 cm in diameter ulcerated nodular lesion on the left face, is reported. The skin nodule was surgically excised and assessed by histopathology, including an immunohistochemistry method applied for the first time to equine tissues which clearly demonstrated leishmanial amastigote forms. Two serological determinations with the direct agglutination test performed 13 months apart showed seroconversion specific for Leishmania from a <25 to a 200 antibody titre. Polymerase chain reaction followed by kinetopl...
Verrucous hemangioma with pseudoepitheliomatous epidermal hyperplasia in an adult horse. Verrucous hemangiomas are a rare specific variant of equine skin tumors not well described in the literature. An 8-year-old gelding presented a unilateral lesion on the pastern. Macroscopically, the mass showed a warty and verrucous surface with focal ulcerations. The histology showed a dermal proliferation of endothelial-layered capillaries and venules separated by a delicate stroma of scant fibroblasts and collagen deposition, with pseudoepitheliomatous hyperplasia (exuberant reactive irregular epithelial hyperplasia with tongue-like projections extending into the dermis, mimicking downgrowt...
Sarcoids. Sarcoids are the most common skin tumors seen in horses worldwide. The pathogenesis of sarcoids is multifactorial, including an association with bovine papillomavirus types 1 and 2 and a genetic susceptibility to tumor development. Clinical manifestations vary and include occult, verrucous, nodular, fibroblastic, mixed, and malignant (malevolent) types. The tumor is nonmetastasizing but can become very aggressive locally. Multiple tumors are common. All clinical types can be present in the same horse. No treatment protocol is universally effective. The tumor has a high risk of recurrence. Recu...
Heritable equine regional dermal asthenia. Hereditary equine regional dermal asthenia is a form of Ehlers-Danlos syndrome, and has an autosomal recessive mode of inheritance. Affected horses are typically born normal and develop lesions within the first 2 years of life. The most common symptoms of the disease include stretchy, loose skin that feels doughy or mushy. More severely affected horses experience spontaneous skin sloughing and extensive lacerations, hematomas, and seromas from minor trauma. Affected horses have a higher than expected incidence of corneal ulcers. DNA testing can normal, establish carrier and affected status. Pa...
Immune-mediated dermatoses. Pemphigus foliaceus is the most common autoimmune skin disease in horses and is associated with the production of autoantibodies directed against surface proteins of the keratinocyte. Pemphigus vulgaris is a rare autoimmune skin disease in horses. Systemic lupus erythematosus and cutaneous lupus erythematosus are recognized in horses and both are rare. Bullous pemphigoid is a rare autoimmune disease in horses caused by immunologic attack of the basement membrane zone by autoantibodies. Erythema muliforme is an immunologic reaction in the skin in which keratinocyte cell death is the prominent c...
Equine Pastern Dermatitis. Equine Pastern Dermatitis (EPD) is not a single disease, but a cutaneous reaction pattern of the horse. EPD should be considered a syndrome, rather than a diagnosis. Uncovering the underlying etiology prior to treatment is key to minimizing treatment failures and frustration. To achieve a positive therapeutic outcome, treating the predisposing and perpetuating factors is just as important as addressing the primary cause of EPD. This article reviews clinical signs, differential diagnoses, diagnosis, and treatment of EPD.
Localization of the cutaneus trunci muscle reflex in horses. To determine the magnitude and location of skin movement attributable to the cutaneus trunci muscle reflex in response to localized stimulation of the skin of the dorsolateral aspect of the thoracic wall in horses. Methods: 8 horses. Methods: A grid of 56 reflective markers was applied to the lateral aspect of the body wall of each horse; markers were placed at 10-cm intervals in 7 rows and 8 columns. A motion analysis system with 10 infrared cameras was used to track movements of the markers in response to tactile stimulation of the dorsolateral aspect of the thoracic wall at the levels of T6...
