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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.
Prevalence, number and morphological types of multinucleated histiocytic giant cells in equine inflammatory dermatoses: a retrospective light microscopic study of skin-biopsy specimens from 362 horses. Multinucleated histiocytic giant cells (MHGC) are seen frequently in skin-biopsy specimens from horses with inflammatory dermatoses. However, the prevalence, number and morphological types of these cells have not been reported. Objective: To determine the prevalence, number and morphological types of MHGC in equine inflammatory dermatoses, and the association of these cells with specific conditions. Methods: Skin-biopsy specimens from 335 horses with inflammatory dermatoses and from 27 horses with normal skin were evaluated for the prevalence, number and morphological types of MHGC. Results: T...
Dietetic effects of oral intervention with mare’s milk on the Severity Scoring of Atopic Dermatitis, on faecal microbiota and on immunological parameters in patients with atopic dermatitis. In a double-blind, placebo-controlled crossover trial, 23 patients consumed 250 ml mare's milk or placebo for 16 weeks. The aim was to examine the effects of mare's milk on the characteristics of atopic dermatitis (AD), on faecal microbiota and on clinical and immunological parameters. The intensity of AD was examined using the Severity Scoring of Atopic Dermatitis (SCORAD) index. During the mare's milk period, the mean SCORAD value of patients (n=23; 17 females, 6 males) decreased from 30.1 to 25.3 after 12 weeks (P<0.05) and to 26.7 after 16 weeks (P<0.1). In a subgroup (n=7) the SCORA...
Randomised controlled trial of the treatment of pastern dermatitis with a formulation containing kunzea oil. The efficacy of an ointment containing kunzea oil for the treatment of horses with localised acute or chronic pastern dermatitis was assessed. Thirty-seven horses were randomly allocated to treatment with an ointment containing either 20 per cent kunzea oil (test) or 2 per cent ketoconazole (control). Only 21 of the horses completed the study. The severity of the lesions was assessed before and after seven days of treatment. The kunzea oil formulation resulted in a significant decrease in the median total area of the lesions from 40 cm(2) (range 3 to 252 cm(2)) to 0 cm(2) (range 0 to 34 cm(2))...
Equine skin tumours in 20 horses resembling three variants of human melanocytic naevi. Melanocytic tumours are important in horses, especially grey horses. Intradermal common melanocytic naevi, cellular blue naevi and combined cellular blue naevi are subgroups of human melanocytic tumours, which have not been reported in horses. In this study, we describe 20 horses with skin tumours similar to these naevi of humans. These tumours represented individual skin masses in male and female horses of different breeds. Tumours resembling human intradermal common melanocytic naevi were noted in 12 horses aged between 2 and 17 years. Seven horses aged between 4 and 15 years developed cutan...
Activated platelet-derived growth factor beta receptor expression, PI3K-AKT pathway molecular analysis, and transforming signals in equine sarcoids. The equine sarcoid is the most common dermatologic neoplasm reported in horses. Bovine papillomavirus (BPV) types 1 and 2 are associated with sarcoids, in which the expression of the major transforming oncoprotein (E5) is often recorded. The transformation activity of the virus is due to the binding of the E5 to the platelet-derived growth factor beta receptor (PDGFbeta-r). In the present study, we show by Western blot in 4 sarcoid samples and 3 normal equine skin samples that the PDGFbeta-r is more phosphorylated in sarcoid tissue than in normal skin (P < .001). Furthermore, the physical i...
Complications of equine wound management and dermatologic surgery. Complications of wounds and cosmetic surgery can be accurately managed with a combination of timely surgical and medical intervention to ensure the best possible outcome. The lack of soft tissue protection and a large quantity of susceptible synovial, tendon, ligament, and neurovascular structures make early and meticulous evaluation of limb wounds critical. Skin grafting is usually used following a period of open wound management and after healthy granulation tissue formation. Penetrating wounds of the abdomen or thorax have a guarded prognosis resulting from the ensuing potential for infecti...
Cutaneous fungal granuloma in a horse. This case report describes a 4-year-old-horse with two cutaneous masses on the right crest of the neck. Biopsy revealed chronic nodular pyogranulomatous dermatitis and panniculitis. Giemsa and periodic acid-Schiff stains showed focal spherical, yeast-like organisms. A diagnosis of cutaneous fungal granuloma was made. The size of the masses decreased after oral treatment with fluconazole for 10 days combined with potassium iodide for 30 days, and the remaining masses were excised by laser. Lesions did not recur at the site. Fungal granuloma should be considered as a differential diagnosis in ho...
Influence of time of day on body temperature, heart rate, arterial pressure, and other biological variables in horses during incremental exercise. We examined the response to exercise of selected physiological variables in horses performing the identical routine for eight days, in the morning (a.m.) or in the afternoon (p.m.). Heart rate (HR), systolic and diastolic blood pressure (BP), and body temperature (BT) were all consistently greater in the p.m. For BP and BT, the absolute increase above the a.m. values was the same at rest and during exercise. For HR, the absolute increase was greater during exercise, but the percent increase was the same as during rest. During exercise, blood glucose decreased, while blood lactate and skin temp...
Quantitative and qualitative evaluation of dermal elastin of draught horses with chronic progressive lymphoedema. Chronic progressive lymphoedema (CPL) in horses, a disease of certain draught breeds, is associated with altered elastin metabolism. The characteristic lesions are seen in the skin of the lower (distal) limbs. This study was based on horses of susceptible breeds, with and without CPL, and on horses of a non-susceptible breed. Skin samples were obtained for examination from the neck (considered a non-affected region) and from the distal limb. The skin lesions were characterized histologically and the dermal elastic fibres were evaluated morphologically and quantitatively. In all horses the mean...
Assessing techniques for disinfecting sites for inserting intravenous catheters into the jugular veins of horses. 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 ...
Nucleotide structure and expression of equine pigment epithelium-derived factor during repair of experimentally induced wounds in horses. To clone full-length equine pigment epithelium-derived factor (PEDF) complementary DNA (cDNA) and to evaluate its temporal expression during repair of wounds in horses. Methods: 4 clinically normal 2-to 3-year-old Standardbred mares. Methods: Full-length equine PEDF cDNA was cloned by screening size-selected cDNA libraries derived from biopsy specimens obtained from the wound edge 7 days after experimental creation of a 6.25-cm(2) full-thickness wound in the skin of the lateral thoracic wall. Expression was evaluated in normal skin and in biopsy specimens obtained weekly from experimentally in...
Evaluation of four topical preparations for the treatment of cannon hyperkeratosis in a horse. The response to treatment with four topical preparations was evaluated in an 11-year-old Morgan horse mare with histologically confirmed quadrilateral cannon hyperkeratosis. Each limb was treated for 30 days with 0.1% tacrolimus ointment, 0.1% adapalene gel, 0.2% phytosphingosine spray or a water-based emollient. Response to treatment was evaluated both histologically and visually. A water-based emollient and 0.1% tacrolimus ointment produced encouraging clinical responses. Pre-treatment histopathology identified marked, mostly compact, hyperkeratosis and follicular hyperkeratosis, most promin...
Expression of platelet-derived growth factor-beta receptor and bovine papillomavirus E5 and E7 oncoproteins in equine sarcoid. Equine sarcoids are benign fibroblastic skin tumours that are recognized throughout the world. Infection with bovine papillomavirus (BPV) types 1 and 2 has been implicated as a major factor in disease development; however, the cellular mechanisms underlying fibroblast transformation remain poorly defined. The present study further characterizes aspects of the association with BPV in 15 equine sarcoids. BPV DNA was demonstrated in 12/15 tumours collected from different areas of Italy. Nine of these 12 tumours expressed the BPV oncoproteins E5 and E7, but these oncoproteins were not expressed by...
Generalized sarcoidosis in two horses. Equine sarcoidosis is a rare disorder usually characterized by exfoliative dermatitis, moderate to severe wasting, and sarcoidal granulomatous inflammation of multiple organ systems. It has an unknown aetiopathogenesis. The condition is not related to equine sarcoid. This case report describes generalized cutaneous and systemic sarcoidosis in an 11-year-old Trakehner mare (case A) and in a 7-year-old Dutch Warmblood gelding (case B). Case A was presented with cutaneous sarcoidosis on the head and body and was diagnosed on the basis of histological examination of skin. Case B presented with mul...
A histamine release assay to identify sensitization to Culicoides allergens in horses with skin hypersensitivity. Skin hypersensitivity is an allergic disease induced in horses by allergens of Culicoides midges. The condition is typically diagnosed by clinical signs and in some horses in combination with allergy testing such as intradermal skin testing or serological allergen-specific IgE determination. Here, we describe an alternative method for allergy testing: a histamine release assay (HRA) that combines the functional aspects of skin testing with the convenience of submitting a blood sample. The assay is based on the principle that crosslinking of allergen-specific IgE bound via high-affinity IgE rec...
Ultrastructural changes in regressing equine sarcoid tumours–mysterious role of mitochondria. Mitochondrial changes of healing sarcoids were followed in 17 affected horses. Biopsies of this fibroblastic skin tumour were collected both before and during the treatment and tumour regression. The therapy consisted of the partial excision of tumours, repeated immunizations with autogenous polymerized tumour particles and supportive dietary treatment with stannic chloride and folic acid. Presence of transformed, electron-dense mitochondria in different phases of healing was studied by successive biopsy from regressing tumours. Additionally, the relation of these transformed mitochondria to t...
Cutaneous pythiosis in a nontravelled California horse. An 18-year-old Arabian mare was examined with a large mass on the left hind pastern and fetlock. The mare was located in the Central Valley of northern California, and had never been out of the state. Routine histopathological processing and examination of biopsy samples from the mass showed several hyphal organisms that were delineated with a silver stain. Using immunohistochemistry the organism was diagnosed as Pythium insidiosum. The owner declined debulking surgery, and despite treatment with an immunotherapeutic vaccine, the horse's condition deteriorated leading to euthanasia.
Seroprevalence of anti-Borrelia burgdorferi antibodies in dogs and horses in Turkey. The aim of the study was to determine the seroprevalence of anti-Borrelia burgdorferi antibodies in a population of Turkish dogs and horses, as well as to compare the sensitivity of novel flow-cytometry-based borreliacidal antibody test (BAT) with ELISA assay. Serum samples collected from 400 dogs and 300 horses were tested with enzyme-linked protein A/G assay (ELPAGA), using Borrelia whole cell antigens. ELPAGA test showed 93 dogs (23.2%) and 18 horses (6%) serologically positive for anti-Borrelia antibodies. In parallel testing of sera with BAT, we found 27.75% positive dogs and 6.33% positi...
Eprinomectin treatment of psoroptic mange in hunter/jumper and dressage horses: a prospective, randomized, double-blinded, placebo-controlled clinical trial. The purpose of this prospective, double-blinded, placebo-controlled clinical trial was to investigate the efficacy of topical eprinomectin for the treatment of psoroptic mange infestation in horses. 24 privately owned hunter/jumper and dressage horses were diagnosed with psoroptic mange infestation based on physical findings and skin scraping results were enrolled and randomly assigned to either topical eprinomectin pour-on solution (at a dose of 500microg/kg body weight weekly once for four applications) treatment group or a placebo group (purified water). Clinical evaluations and skin scrapi...
Seasonal influences on quantitative changes in sweat-associated anatomy in native and thoroughbred horses. Stereological techniques were used to assess seasonal influences on morphometric characteristics of hair follicles, sweat and sebaceous glands in abattoir pelts of ponies (PN), thoroughbred (TB) and non-thoroughbred (NTB) horses. Volume density of sweat glands increased significantly from winter (0.061) to summer (0.098) in TB, and showed no change in NTB and a positive tendency in PN. There might be a body surface area : volume effect for sweat gland parameters as PN had smaller values than either TB or NTB, probably attributable to control of heat loss in winter. In summer, the skin remained...
Dermatophytoses in animals. Dermatophytoses are one of the most frequent skin diseases of pets and livestock. Contagiousness among animal communities, high cost of treatment, difficulty of control measures, and the public health consequences of animal ringworm explain their great importance. A wide variety of dermatophytes have been isolated from animals, but a few zoophilic species are responsible for the majority of the cases, viz. Microsporum canis, Trichophyton mentagrophytes, Trichophyton equinum and Trichophyton verrucosum, as also the geophilic species Microsporum gypseum. According to the host and the fungal spec...
Validity of indicators of dehydration in working horses: a longitudinal study of changes in skin tent duration, mucous membrane dryness and drinking behaviour. Dehydration is a serious welfare concern in horses working in developing countries. Identification of a valid and practical indicator of dehydration would enable more rapid treatment and prevention. Objective: To examine changes in bodyweight, clinical and blood parameters during rehydration of working horses, identify a 'gold standard' criterion for dehydration and use this to validate a standardised skin tent test, drinking behaviour and mucous membrane dryness as potential field indicators. Methods: Fifty horses with a positive skin tent test, working in environmental temperatures of 30-44 ...
Short term analgesic effect of extracorporeal shock wave therapy in horses with proximal palmar metacarpal/plantar metatarsal pain. Extracorporeal shock wave therapy (ESWT) is an accepted form of treatment for chronic cases of proximal suspensory desmitis (PSD). Subjective evaluation of horses shortly after being treated with ESWT has led clinicians to comment on an immediate reduction in lameness. This study aimed to evaluate the analgesic effect of ESWT on 16 horses with PSD or PSD-like pain in a fore- or hindlimb. To objectively assess lameness, gait analysis was performed on an instrumented treadmill before and 6, 24, 48 and 72h after ESWT of the origin of the suspensory ligament and the results compared to the effects...
Prevalence and body distribution of sarcoids in South African Cape mountain zebra (Equus zebra zebra). There are no reports in the literature describing any tumours, and specifically sarcoids, in zebras. The equine sarcoid, a locally aggressive, fibroblastic skin tumour, is the most common dermatological neoplasm reported in horses. The Cape mountain zebra (CMZ) has been described as one of the most vulnerable mammals in South Africa with current populations existing in isolated units. All South African CMZ are descendants from no more than 30 individual animals originating from 3 populations, namely the Mountain Zebra National Park, and Kammanassie and Gamka Mountain Nature Reserves near Crado...
Dermatitis in a horse associated with the poultry mite (Dermanyssus gallinae). This is the first documented case report of dermatitis associated with the poultry mite (Dermanyssus gallinae) in a horse. It occurred in a 16-year-old horse that was in contact with domestic hens. Clinical signs consisted of severe pruritus, with self-induced hair loss mainly on the head. Despite the multiple skin scrapings performed during both day- and nighttime, mites were only isolated from the in-contact poultry and from the horse's environment, and not the horse. The animal was treated using a 2% permethrin solution, sprayed on the entire body once a week for 4 weeks, and by decontamina...
