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.
Stahl J, Braun M, Siebert J, Kietzmann M.A water based combination of 0.1% octenidine dihydrochloride and 2% 2 - phenoxyethanol is registered in many European countries as an antiseptic solution (octenisept®) for topical treatment with high antimicrobial activity for human use, but octenidine based products have not been registered for veterinary use yet. The aim of the present study was to investigate whether octenidine dihydrochloride or 2 -phenoxyethanol, the two main components of this disinfectant, permeate through animal skin in vitro. Therefore, permeation studies were conducted using Franz-type diffusion cells. 2 ml of the t...
Poore LA, Else RW, Licka TL.Verrucous pastern dermatitis is a progressive inflammatory skin disease commonly involving the palmar or plantar aspects of the pasterns of horses. There are no reports of successful surgical treatment for multifocal circumscribed verrucous masses in the chronic stages of verrucous pastern dermatitis. A combination of sharp dissection and electrocautery was used to resect numerous multifocal circumscribed verrucous masses from the distal hindlimb of an 11-year-old gelding draught horse. There was no evidence of significant regrowth or complications at a 24 month postoperative examination.
Stepnik CT, Outerbridge CA, White SD, Kass PH.This retrospective study reports on the clinical presentation of equine atopic skin disease and evaluates response to treatment with allergen-specific immunotherapy (ASIT) based on intradermal testing and/or serum testing. Computerized medical records from January 1991 to December 2008 yielded 54 horses included in the study. Presenting clinical signs (CS) included urticaria (n=28), pruritus (n=8) or both (n=18). Forty-one of 54 horses received ASIT, and response to ASIT (n=32) was evaluated via telephone survey. Eighty-four per cent (n=27) of owners reported that ASIT reduced their horse's CS...
Deschene K, Céleste C, Boerboom D, Theoret CL.As a transient hypoxic state exists within skin wounds in horses and may be important for the healing process, this study sought to identify a molecular hypoxia response occurring in horse limb and body wounds healing by second intention. Hypoxia-inducible factor 1α (HIF1α) protein expression was studied throughout repair by Western blotting and immunofluorescence. Paradoxically, HIF1α was strongly expressed in intact skin and its expression decreased dramatically following wounding (p<0.01), despite the expected hypoxic state within the wounded tissue. HIF1α levels reincreased in parallel...
Marshall VL, Secombe C, Nicholls PK.A 6-week-old Warmblood colt foal was presented for investigation of multiple haematoma formation in various locations, poor wound healing and abnormal scar formation. Based on the history and clinical presentation of hyperextensible skin with prolonged skin tenting, the foal was diagnosed with cutaneous asthenia and euthanased because of the poor prognosis. Histopathological and electron microscopic findings were inconclusive. This is the first case report of cutaneous asthenia in a Warmblood horse in Australia. Cutaneous asthenia is reviewed with particular reference to hereditary equine regi...
Stadler S, Kainzbauer C, Haralambus R, Brehm W, Hainisch E, Brandt S.Based on the anecdotally reported eradication of a sarcoid using aciclovir cream, the curative potential of this ointment was investigated in 22 sarcoid-affected horses referred to the Equine Clinic Tillysburg, Austria, between 2006 and 2009. Sarcoid disease was diagnosed by clinical examination and bovine papillomavirus types 1 and 2 from intact skin and tumour tissue. As nine horses had more than one lesion, a total of 47 sarcoids were treated by daily topical application of aciclovir 5 per cent cream for a period of two to six months; in four horses, surgical tumour ablation was performed b...
van den Boom R, Kempenaars M, van Oldruitenborgh-Oosterbaan MM.Insect bite hypersensitivity (IBH) is the most common cause of pruritus in horses and is a serious welfare issue for affected animals. In this study, the effect of a topical phytogenic ointment on the healing of cutaneous lesions was investigated in a double-blind trial involving 26 horses with I B H. The number of lesions and their total surface area were recorded on days 0, 7, and 21 in horses treated for 3 weeks with either verum or placebo ointment. After unblinding of treatment assignment, the horses that had been treated with the placebo ointment received the verum preparation for an add...
Kim DY, Johnson PJ, Senter D.A 9-year-old Tennessee Walking Horse gelding was presented for diagnosis of the cause of extensive alopecia. Complete hair loss was noted over the head, neck, shoulder, thigh, and proximal limbs, but the trunk, distal limbs, pelvic area, mane, and tail were unaffected. The alopecic areas were visually noninflammatory with no exudate or crust except on the shoulder and along the back, where multifocal patchy areas of alopecia with scales and crust were evident. The horse was slightly pruritic. Microscopically, the hair bulbs, inner and outer root sheaths of inferior segments, and perifollicular...
Burns RE, Pesavento PA, McElliott VR, Ortega J, Affolter VK.Three horses presented with variably painful, nonulcerated masses of the head or neck that were diagnosed as glomus tumours. Grossly, they were fleshy, pink to tan masses ranging from 0.4 to 9 cm in diameter, involving either the deep dermis and subcutis or the subcutis and underlying skeletal muscle. Microscopically, neoplastic epithelioid cells were arranged in sheets, cords and packets within lobules. The neoplastic cells frequently abutted and formed nodular bulges into large endothelium-lined vascular spaces, especially around the tumour periphery. Large nerve branches were associated wit...
Brandt S, Tober R, Corteggio A, Burger S, Sabitzer S, Walter I, Kainzbauer C, Steinborn R, Nasir L, Borzacchiello G.In equids, bovine papillomaviruses of type 1 (BPV-1) and less frequently type 2 induce common, locally aggressive skin tumours termed sarcoids. Whereas BPV infection in cattle usually involves the epidermis and is productive in this skin layer, infection in equids is currently thought to be abortive, with virus solely residing as multiple episomes in dermal fibroblasts. Based on recent observations that do not agree with this assumption, we hypothesised that BPV also infects equid epidermis and is active in this skin layer. To test this hypothesis, we conducted a proof-of-principle study on ei...
Dicken M, Munday JS, Archer RM, Mayhew IG, Pandey SK.Equine cutaneous fungal granulomas have been previously referred to in New Zealand (Fairley 1998), and are described in the veterinary literature from around the world, including North America and Australia (Pascoe and Summers 1981; Genovese et al. 2001; Valentine et al. 2006), but no peer-reviewed reports appear published in the literature in New Zealand. Described here is a case of multiple cutaneous fungal granulomas caused by Alternaria spp. in a horse in New Zealand.
Heimann M, Janda J, Sigurdardottir OG, Svansson V, Klukowska J, von Tscharner C, Doherr M, Broström H, Andersson LS, Einarsson S, Marti E....Equine insect bite hypersensitivity (IBH) is a seasonally recurrent, pruritic skin disorder caused by an IgE-mediated reaction to salivary proteins of biting flies, predominantly of the genus Culicoides. The aim of this study was to define T cell subsets and cytokine profile in the skin of IBH-affected Icelandic horses with particular focus on the balance between T helper (Th) 1, Th2 and T regulatory (Treg) cells. Distribution and number of CD4+, CD8+ and Forkhead box P3 (FoxP3)+ T cells were characterized by immunohistochemical staining in lesional and non-lesional skin of moderately and seve...
McGowan TW, Pinchbeck G, Phillips CJ, Perkins N, Hodgson DR, McGowan CM.To describe the prevalence and risk factors for clinical signs of disease and owner-reported health or welfare issues of aged horses in Queensland, Australia. Methods: Owners of horses were contacted via an equestrian organisation in Queensland and asked to complete a questionnaire about their horses aged 15 years and older, to gain information about clinical signs observed in the horse and disease history. Owners were asked to identify health or welfare issues they felt were important in aged horses. Results: Owners were able to identify many clinical signs of disease, with 83% of horses havi...
Dart AJ, Dart CM, Dudhia J, Perkins N, Canfield P, Smith RK.To evaluate whether wound type or site influence the production of cartilage oligomeric matrix protein (COMP) and transforming growth factor β1 (TGF-β1), and determine if there is a correlation between TGF-β1and COMP during healing. Methods: Experimental. Methods: Standardbred horses (n=6), 4-8 years old. Methods: Six, standardized, full-thickness skin wounds (open, straight, and elliptical) were surgically created on the neck (n=3) and metacarpus (3) on each horse. Wounds were randomly allocated to site and side. Tissue samples were collected before creating wounds and on days 7, 14, and 4...
Reeves WK, Miller MM.Organic insect repellents are of interest to many agricultural producers and animal owners. Geraniol, a plant-derived alcohol, is naturally produced by a wide range of plants and is a US Environmental Protection Agency minimum risk pesticide. Previous studies have shown various concentrations of geraniol repel or kill mosquitoes; however, geraniol might cause allergic contact dermatitis in humans or animals. We tested a commercially available 2% aqueous solution of geraniol on ponies as a mosquito repellent. Five trials were conducted on ponies treated with a 60-ml aerosol mist (30 ml per side...
Chen H, Wang L, Zeller M, Hornshaw M, Wu Y, Zhou M, Li J, Hang X, Cai J, Chen T, Shaw C.From defensive skin secretions acquired from two species of African hyperoliid frogs, Kassina maculata and Kassina senegalensis, we have isolated two structurally related, C-terminally amidated tridecapeptides of novel primary structure that exhibit a broad spectrum of biological activity. In reflection of their structural novelty and species of origin, we named the peptides kassorin M (FLEGLLNTVTGLLamide; 1387.8 Da) and kassorin S (FLGGILNTITGLLamide; 1329.8 Da), respectively. The primary structure and organisation of the biosynthetic precursors of kassorins M and S were deduced from cloned s...
Figueredo LA, Cafarchia C, Otranto D.Fungi of the genus Geotrichum are commonly found in the environment and, in some circumstances, they may cause diseases in humans and animals. Although these fungi have been isolated from skin lesions of some animal species, their pathogenic role in horses remains uncertain. With the aim to investigate the role of Geotrichum candidum as etiological agent of dermatomycoses, a retrospective study of 64 horses presenting skin lesions and suspected to have fungal infections was carried out. For each animal, anamnestic data were recorded and fungal culture were performed using hair. Out of 64 cases...
Schöniger S, Valentine BA, Fernandez CJ, Summers BA.Schwannomas are uncommonly recognized in horses. This study describes cutaneous schwannomas in 22 horses aged 8 to 25 years: 12 male, 7 female, and 3 of unknown sex. The horses had solitary cutaneous masses: 9 on the head, 3 on the neck, and the others on the shoulder, hip, thorax, abdomen, rump, extremities, or tail. The location of 1 tumor was unknown. The dermal tumors were well demarcated and expansile. Twelve had a multinodular pattern, whereas 10 formed a single nodule. Antoni A areas were observed in all tumors, and 10 tumors contained Antoni B areas. In Antoni A areas, the densely pack...
Tranchina MM, Scott DW, McDonough SP.Summary A small population of resident T lymphocytes is present in the healthy human and murine epidermis. However, resident epidermal lymphocytes have not been reported in normal skin of the horse. Skin biopsy specimens from the normal skin of 27 horses were examined histologically and immunohistochemically for the presence of lymphocytes, CD3+ cells and BLA.36+ cells in epidermis and adnexal epithelia. All examinations were negative. It appears that lymphocytes occur rarely, if at all, in the epidermis and adnexal epithelia of normal horse skin. Hence, the presence of lymphocytes in these st...
Bogaert L, Heerden MV, Cock HE, Martens A, Chiers K.Ten equine skin tumors that had been classified as schwannomas on routine histological examination were analyzed by polymerase chain reaction for bovine papillomavirus DNA. All 10 were positive for bovine papillomavirus 1 or 2, and all 10 were immunohistochemically negative for S-100 protein and strongly positive for vimentin. Nine tumors were moderately positive for laminin and 8, for smooth muscle actin. Five tumors were variably and weakly positive for type IV collagen. The lack of S-100 protein expression made Schwann cells an unlikely cell of origin, as opposed to peripheral nerve sheath ...
Rüfenacht S, Roosje PJ, Sager H, Doherr MG, Straub R, Goldinger-Müller P, Gerber V.Chorioptes bovis infestation is a common cause of pastern dermatitis in the horse, with a predilection in draft horses and other horses with thick hair 'feathers' on the distal limbs. The treatment of this superficial mite is challenging; treatment failure and relapse are common. Furthermore, C. bovis infestation may affect the progression of chronic pastern dermatitis (also known as chronic proliferative pastern dermatitis, chronic progressive lymphoedema and dermatitis verrucosa) in draft horses, manifesting with oedema, lichenification and excessive skin folds that can progress to verruci...
Tóth F, Schumacher J, Castro F, Perkins J.To describe and evaluate full-thickness skin grafting of equine wounds. Methods: Case series. Methods: Adult horses (n=6). Methods: A full-thickness graft was harvested from the pectoral region with the horse anesthetized or standing and sedated after local anesthetic infiltration. Grafts were attached to the cutaneous margin of the wound with staples and/or sutures if the horse was anesthetized or if the recipient site was desensitized. Cyanoacrylate glue was used to attach the grafts to the cutaneous margin of the wound of 3 horses. Medical records were reviewed for history, physical examina...
van Zyl A, Daniel J, Wayne J, McCowan C, Malik R, Jelfs P, Lavender CJ, Fyfe JA.Two horses were diagnosed as having Mycobacterium ulcerans infections. The first was a 21-year-old Quarterhorse-cross mare living in Mallacoota (a coastal town near the border of New South Wales and Victoria, Australia) that presented with lichenification, hair-loss and oedema on a fetlock, which subsequently ulcerated, as well as a non-healing ulcer on the wither. The second horse was a 32 year-old Standardbred gelding from Nicholson, near Bairnsdale, Victoria, that had an ulcerated lesion on its caudal thigh. Histologically, there were characteristic changes seen with M. ulcerans infections ...
Rüfenacht S, Straub R, Steinmann B, Winand N, Bidaut A, Stoffel MH, Gerber V, Wyder M, Müller E, Roosje PJ.Hereditary equine dermal asthenia (HERDA) is an autosomal recessive skin disease that affects predominantly Quarter Horses and related breeds. Typical symptoms are easy bruising and hyperextensible skin on the back. The prognosis is guarded, as affected horses cannot be ridden normally and are often euthanised. In the Quarter Horse, HERDA is associated with a mutation in cyclophilin B (PPIB), an enzyme involved in triple helix formation of collagen. Here we describe the case of a Swiss Warmblood filly with symptoms of HERDA without PPIB-mutation and in which we also could exclude Ehlers-Danlos...
Grady JG, Elder SH, Ryan PL, Swiderski CE, Rashmir-Raven AM.Hereditary equine regional dermal asthenia (HERDA) is an autosomal recessive skin disorder that has yet to be fully characterized. HERDA is predominately expressed in Quarter Horses, with the majority of these disseminating from elite cutting horse bloodlines, leading to the increased incidence of HERDA in recent years. Affected horses have loose, hyper-extensible, fragile skin and are frequently euthanized due to poor wound healing and disfiguring scars. This study sought to better characterize HERDA by analysis of the biomechanical parameters of tensile strength, modulus of elasticity, energ...
Sloet van Oldruitenborgh-Oosterbaan MM, van Poppel M, de Raat IJ, van den Boom R, Savelkoul HF.Intradermal tests using a Culicoides nubeculosus extract have proven unreliable for diagnosis of equine insect bite hypersensitivity (IBH) in the Netherlands. The aim of this study was to evaluate the diagnostic value of an extract derived from the Dutch species C. obsoletus and C. pulicaris. Thirteen pairs of horses were tested, each pair consisting of one horse with IBH and the other a healthy control. Each horse was injected intradermally with 0.1 mL of three concentrations of Culicoides whole body extract (1 : 1000 w/v, 1 : 10,000 w/v and 1 : 25,000 w/v), histamine solution (0.01 mg/mL, po...
Paterson S, Coumbe K.Chorioptic mange caused by Chorioptes bovis is a common pruritic skin condition of the horse. This surface-browsing parasite usually affects the lower legs (leg mange) but can present as a generalized skin disease. Numerous anecdotal reports exist in the literature about the benefit of lime sulphur as a treatment for surface ectoparasites in the horse. This report studies the use of lime sulphur when applied as a 5% solution, some with and some without prior shampooing and clipping, to treat confirmed cases of chorioptic mange in 22 horses. Horses included in the trial had clinical signs indic...
Chung TH, Park GB, Lim CY, Park HM, Choi GC, Youn HY, Chae JS, Hwang CY.Identification of the species and strain of dermatophyte can play an effective role in control of disease outbreaks by establishing the source of infection. Current methods of identification are based on cultural and microscopic methods, often involving weeks before a positive identification are made. A rapid molecular diagnostic method would therefore be an important laboratory technique, but requires confirmation in equine clinical practice. Objective: To test the sensitivity and specificity of molecular diagnostic methods applied to a racehorse herd from the Korean Racehorse Authority (KRA)...
Mills PC.The effects of three vehicles, phosphate-buffered saline (PBS), ethanol (50% in PBS w/w) and propylene glycol (50% in PBS w/w) on in vitro transdermal penetration of testosterone was investigated in the horse. Skin was harvested from the thorax of five Thoroughbred horses after euthanasia and stored at -20 degrees C until required. The skin was then defrosted and placed into Franz-type diffusion cells, which were maintained at approximately 32 degrees C by a water bath. Saturated solutions of testosterone, containing trace amounts of radiolabelled [14C]testosterone, in each vehicle were applie...
Hinden S, Klukowska-Rötzler J, Janda J, Marti EI, Gerber V, Roosje PJ.Recurrent urticaria (RU) is a common skin disease of horses, but little is known about its pathogenesis. Objective: The aim of this study was to characterize the inflammatory cell infiltrate and cytokine expression pattern in the skin of horses with RU. Methods: Biopsies of lesional and nonlesional skin of horses with RU (n = 8) and of skin from healthy control horses (n = 8) were evaluated. Methods: The inflammatory cell infiltrate was analysed by routine histology. Immunohistochemistry was used to identify T cells (CD3), B ells (CD79), macrophages (MAC387) and mast cells (tryptase). E...
Söderroos D, Ignell R, Haubro Andersen P, Bergvall K, Riihimäki M.Insect bite hypersensitivity (IBH) associated with biting midges is a common allergic skin disease in horses, reducing the welfare of affected horses. This study investigated the effect of IBH on animal welfare and behaviour and assessed a new prophylactic insect repellent. In total, 30 horses were recruited for a prospective cross-over and case-control study. Clinical signs of IBH, inflammatory markers in skin biopsies and behavioural data (direct observations, motion index) were scored longitudinally during two consecutive summers. No differences were observed in the total number of itching...
Müller A, Glüge S, Vidondo B, Wróbel A, Ott T, Sieme H, Burger D.Prediction of impending foaling is highly desirable as early intervention may improve mare and foal outcomes. However, monitoring the peripartum mare is a time-consuming challenge for breeders and many foaling prediction systems have limitations. "Heating up" of the mare is empirically used by breeders as a sign of upcoming parturition in mares. The purpose of this study was to investigate if an increase in skin temperature shortly before parturition is detectable and to determine whether such physiological changes could be an additional valuable parameter to predict foaling. For that, 56 foal...
Geraghty TE, Love S, Taylor DJ, Heller J, Mellor DJ, Hughes KJ.The sites of insertion of catheters into the jugular veins of six horses were investigated to determine common isolates and to assess the effectiveness of two disinfection protocols with the hair coat left long, clipped or shaved. Skin commensals (Staphylococcus, Streptococcus and Micrococcus species) and environmental contaminants (Bacillus, Enterobacteriaceae, Aspergillus and Mucor species) were the microorganisms most frequently isolated. Chlorhexidine gluconate and povidone-iodine-based skin disinfection protocols resulted in significant reductions in the number of bacterial isolates from ...
French DD, Klei TM, Foil CS, Miller RI, Foil LD, Chapman MR, McClure JJ.The efficacy of a single dose of ivermectin (0.2 mg/kg), in injectable or paste formulations, against microfilariae of Onchocerca cervicalis and associated skin lesions was evaluated in 20 naturally infected horses during midsummer months in Louisiana. All horses had clinical signs of dermatitis of the ventral midline and/or limbs, shoulders, thorax, and withers. Efficacy was monitored at 21, 42, and 63 days after treatment. Procedures done at these intervals included microfilarial counts of 6-mm skin biopsy specimens of affected ventral midline, grading of gross lesions, and photography and h...
Weese JS, Yu AA.Bacterial, dermatophilosis, and superficial ringworm infections are common skin diseases noted in equine dermatology. The ability to recognize and accurately diagnose the skin condition is key to selecting an appropriate and successful treatment regimen. Addressing underlying etiology, environmental management, and infection control play a crucial role in preventing relapse of clinical signs.
Cochrane CA, Freeman KL, Knottenbelt DC.Wound healing in equidae is delayed and more complicated than in other species. These complications arise from a condition known as exuberant granulation tissue formation. The lower limb of the horse is frequently slower to heal than other parts of the body and has a particular tendency to produce excess (exuberant) granulation tissue. Sarcoids are tumor-like lesions of the skin which often appear at the site of wounds. This study compared the growth characteristics of the sarcoid and granulation tissue-derived cells with normal dermal fibroblasts grown from primary cell cultures. All three ce...
Requena L, de la Cruz A, Moreno C, Sangüeza O, Requena C.Animal type melanoma is a rare histopathologic variant of melanoma characterized by sheets and nodules of heavily pigmented epithelioid melanocytes that involve the entire thickness of the dermis. This human neoplasm mimics melanocytic neoplasms seen in gray horses and laboratory animals; thus, is termed animal type melanoma. It is quite rare and, with only a few reported cases, its biological behavior is not well understood. We report an example of animal type melanoma on the back of a 27-year-old man. The lesion showed areas of melanoma in situ, which ruled out the possibility of metastatic ...
Ressel L, Ward S, Kipar A.Equine cutaneous mast cell tumours (CMCTs) are generally considered to be benign skin lesions, although recurrent and multicentric tumours have been described. For canine CMCTs, grading and prognostic approaches are well established and aberrant KIT expression as well as high proliferation indices are associated with poor outcome. However, in the case of equine CMCTs, morphological features, proliferative activity and KIT expression pattern have not been assessed or related to biological behaviour, and there is discussion as to whether CMCTs are true neoplastic processes. The present study des...
Davids BI, Davidson MJ, TenBroeck SH, Colahan PT, Oli MW.To compare the efficacy of sterile preoperative skin antisepsis using either a 5-minute mechanical preparation or 5-minute non-mechanical preparation with chlorhexidine gluconate 4% solution. Methods: Matched design, ANOVA. Methods: Healthy adult Thoroughbred horses (n = 30). Methods: Each horse had both surgical preparation methods randomly assigned to identical sites on the left or right upper thigh. Prepared sites were sampled and cultured for bacteria after each preparation step. Results: Mechanical and non-mechanical preparation techniques significantly reduced bacteria isolated from ...
Essig CM, Merritt JS, Stubbs NC, Clayton HM.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...
Ferrari G, Pang LY, De Moliner F, Vendrell M, Reardon RJM, Higgins AJ, Chopra S, Argyle DJ.Bleomycin is a chemotherapy agent that, when administered systemically, can cause severe pulmonary toxicity. Bleosome is a novel formulation of bleomycin encapsulated in ultra-deformable (UD) liposomes that may be applicable as a topical chemotherapy for diseases such as non-melanoma skin cancer. To date, the ability of Bleosome to effectively penetrate through the skin has not been evaluated. In this study, we investigated the ability of Bleosome to penetrate through ex vivo skin explants from dogs and horses. We visualized the penetration of UD liposomes through the skin by transmission elec...
Steckel RR, Page EH, Geddes LA, Van Vleet JF.The effect of low-level direct-current stimulation on skin wound healing in the horse was assessed. Self-sustaining electrical circuits with electrodes were implanted subcutaneously in or near the wound. Stimulation by direct current (10 or 20 microA) was used to determine the effect on equine skin healing. The efficacy of electrotherapy was evaluated by sequentially comparing the clinical appearance of the wound and measuring the size of the granulating wound bed. The histologic appearance of the healing stimulated wounds was compared with that in nonstimulated control wounds created on 9 hor...
Dahm AM, de Bruin A, Linat A, von Tscharner C, Wyder M, Suter MM.We describe the establishment and characterisation of equine keratinocyte cultures with maintenance of a high proliferative capacity up to the second passage. Improved attachment and growth were obtained by seeding primary cells on equine feeder layers. Subcultured keratinocytes showed optimal growth when seeded on collagen type I. The proliferation rate of cells on this substrate exceeded that seen for cells seeded on equine feeder layers. By immunohistochemistry, epithelial origin and state of differentiation of the equine keratinocytes were determined. They expressed keratin and desmoplakin...
Poore LA, Else RW, Licka TL.Verrucous pastern dermatitis is a progressive inflammatory skin disease commonly involving the palmar or plantar aspects of the pasterns of horses. There are no reports of successful surgical treatment for multifocal circumscribed verrucous masses in the chronic stages of verrucous pastern dermatitis. A combination of sharp dissection and electrocautery was used to resect numerous multifocal circumscribed verrucous masses from the distal hindlimb of an 11-year-old gelding draught horse. There was no evidence of significant regrowth or complications at a 24 month postoperative examination.
Gunson DE, Halliwell RE, Minor RR.A 2-year-old female horse had large areas of hyperextensible, fragile skin that were interspersed with areas of normal skin. Affected skin tore easily and contained reduced amounts of dermal collagen. Collagen fibers were fragmented and disorganized, and in trichrome-stained sections, many fibers had abnormal red-stained centers. Electron microscopy showed that many collagen fibers had discrete foci of degradation in which the fibrils were fragmented, loosely packed, and widely separated by granular material. Collagen fibril fragments were present in secondary lysosomes in dermal fibroblasts, ...
Semik E, Ząbek T, Gurgul A, Fornal A, Szmatoła T, Pawlina K, Wnuk M, Klukowska-Rötzler J, Koch C, Mählmann K, Bugno-Poniewierska M.In this study, for the first time we report the genome-wide DNA methylation profile of skin tumour in horses and describe differentially methylated genomic regions (DMRs) with respect to healthy skin. Methods: The comparative analysis of DNA methylation patterns detected using Reduced Representation Bisulfite Sequencing (RRBS) technique, allowed identification of 136 regions showing differential methylation between sarcoid and normal skin tissue. Results: Most of the identified DMRs were short fragments, less than 1 kb in size, located in the intergenic regions. Among identified DMRs there wer...
Schumacher J, Hanselka DV.Free autogenous skin grafting of the horse is indicated for wounds too large to heal by contraction and epithelization. Techniques of pinch, punch, tunnel, and sheet grafting are described. Allografting and storage of skin for delayed grafting are discussed.
Huhmann R, Mueller RS.Topical application of polyunsaturated fatty acids (PUFAs) has shown satisfactory results in dogs and humans with allergic skin diseases. Urea and glycolic acid act as keratolytics and moisturizers. Culicoides hypersensitivity is the most common equine hypersensitivity disorder and only limited treatment options exist. Objective: To evaluate the effect of a cream containing topical PUFAs, humectants and emollients on clinical signs of equine Culicoides hypersensitivity. Methods: Privately owned horses (n = 28) with clinical signs of Culicoides hypersensitivity. Methods: For a period of four ...
Kurotaki T, Narayama K, Arai Y, Arai S, Oyamada T, Yoshikawa H, Yoshikawa T.Histopathologic and electron microscopic observations were given on Langerhans cells (LCs) within the follicular epithelium (FE) and intradermal sweat duct (ISD) of equine "Kasen". By light microscopy, LCs were present in the greatest numbers within the FE and ISD than within the epidermal layer and the normal skin, with an occasional formation of several aggregated foci. By electron microscopy, LCs within the FE and ISD widely extended their dendritic processes between the keratinocytes and contained Birbeck granules (Bgs), mitochondria, rough endoplasmic reticula and ribosomes in the cytopla...
Equine mesenchymal stem cells (MSC) of various origins have been identified in horses, including MSCs from the bone marrow and adipose tissue. However, these stem cell sources are highly invasive in sampling, which thereby limits their clinical application in equine veterinary medicine. This study presents a novel method using an air-liquid interface to isolate stem cells from the hair follicle outer root sheath of the equine forehead skin. These stem cells cultured herewith showed high proliferation and asumed MSC phenotype by expressing MSC positive biomarkers (CD29, CD44 CD90) while not e...
Nankervis KJ, Tranquille CA, Chojnacka K, Tacey JB, Deckers I, Newton JR, Murray RC.Water treadmill (WT) exercise may induce limb and back kinematics that meet specific training and rehabilitation goals. The study aimed to investigate the effects of walk speed, at different water depths (WDs), on limb and back kinematics of six Thoroughbreds exercising on a WT. Horses walked at 2.8/4.3/5.5/6.0 km/h (i.e. 0.8/1.2/1.5/1.7 m/s) at dry, metacarpophalangeal and carpal WD. Videography captured limb movement in the sagittal plane. Motion-capture measured thoracolumbosacral flexion-extension (FE), and lateral bend (LB) ranges of movement (ROM) using skin surface markers on the sixt...
Andersson L.The Grey allele in horses is causing premature hair greying and susceptibility to melanoma. The causal mutation is a 4.6 kb tandem duplication in intron 6 of the Syntaxin 17 gene. A recent study demonstrated that the most common allele at the Grey locus (G3) involves three tandem copies of this sequence, whilst a more rare allele (G2) has two tandem copies and the wild-type allele (G1) only one copy. The G3 allele is causing fast greying and high incidence of skin melanoma, whereas the G2 allele is causing slow greying and no obvious increase in melanoma incidence. Further somatic copy number ...
Rubin CJ, Hodge M, Naboulsi R, Beckman M, Bellone RR, Kallenberg A, J'Usrey S, Ohmura H, Seki K, Furukawa R, Ohnuma A, Davis BW, Tozaki T, Lindgren G....The Greying with age phenotype in horses involves loss of hair pigmentation whereas skin pigmentation is not reduced, and a predisposition to melanoma. The causal mutation was initially reported as a duplication of a 4.6 kb intronic sequence in Syntaxin 17. The speed of greying varies considerably among Grey horses. Here we demonstrate the presence of two different Grey alleles, G2 carrying two tandem copies of the duplicated sequence and G3 carrying three. The latter is by far the most common allele, probably due to strong selection for the striking white phenotype. Our results reveal a rem...
Tranquille CA, Chojnacka K, Murray RC.There has been little investigation into the health patterns of the eventing horse population outside veterinary clinics. To target health problems in the eventing horse population, it is important to determine the relative impact of different health problems. The objectives were to describe the prevalence and patterns of lameness/illness in registered British eventing horses. An online survey was released for all horses registered with British eventing in 2018. Data were collated and descriptive analyses undertaken. A total of 1677 surveys were completed, among which 49.4% reported a previous...
Sievers J, Distl O.The Rhenish German draught horse is an endangered German horse breed, originally used as working horse in agriculture. Therefore, the objective of this study was to evaluate the breed's genetic diversity using pedigree and genomic data in order to analyze classical and ancestral pedigree-based inbreeding, runs of homozygosity, ROH islands, and consensus ROH. Methods: We studied the genome-wide genotype data of 675 Rhenish German draught horses and collated pedigree-based inbreeding coefficients for these horses. The final dataset contained 64,737 autosomal SNPs. Results: The average number of ...
Roberts JH, Zhang J, David F, McLean A, Blumenshine K, Müller-Alander E, Halper J.Degenerative Suspensory Ligament Desmitis (DSLD) negatively impacts connective tissues in horses, which often leads to progressive chronic pain and lameness. DSLD has been shown to be a systemic disorder that affects multiple body systems, including tendons, sclerae, and the aorta. Currently, the diagnosis is confirmed by post mortem histological examination of a tendon or suspensory ligament. Histology reveals inappropriate accumulations of proteoglycans in the tendons and other tissues in DSLD-affected horses. Unfortunately, there is no reliable method to diagnose DSLD in living horses. Rece...
Little CB, Kabay MJ.The deep fungal dermatoses that have been reported in Australia have involved Hyphomyces destruens (Hutching and Johnston 1972; Connole 1973; Johnston and Henderson 1974; Miller and Campbell 1982). Entomephthora coronata (Hutching and Johnston 1972; Connole 1973; Miller and Campbell 1982), and Basidobolus haptosporus (Miller and Campbell 1982). These subcutaneous mycoses have occurred on the legs, ventral chest and abdomen (H. destruens), lateral trunk and face (B. haptosporus) and external nares (E. coronata). Metastases to regional lymph nodes are rare (Murray et a1 1979). In a review...
