Wound healing... Enhanced by... Warm clean moist environment. Good blood supply

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1 Wound healing... Enhanced by... Warm clean moist environment. Good blood supply Inhibited by... Infection, necrotic tissue. Movement Poor blood supply Steroids Systemic disease malnutrition

2 Wound Healing After the initial wound there will be an inflammatory phase of about 5 days with the influx of neutrophils etc This is followed by the granulation phase when the deficit will fill with granulation tissue. There will also be a degree of wound contraction. The wound will then undergo epithelialisation as epithelial cells migrate over the surface, this occurs at a rate of about 1mm/10 days.

3 Exuberant granulation tissue proud flesh, a common complication of equine wound healing, particularly lower limb wounds Proud flesh inhibits epithelialisation

4 The formation of proud flesh can be inhibited by keeping the wound environment free of infection warm and moist by the use of dressings, bandages and antibiotics. If proud flesh does form it can be trimmed back with a scalpel to allow epithelialisation of the wound bed, which will be inhibited by the presence of proud flesh.

5 wound contraction This is an important part of wound healing in certain wounds, particularly on the body it is less efficient in limb wounds. The contraction is effected by myofibroblasts which help draw the edges of the wound together, promoting fast healing.

6 Wound Management Control haemorrhage Debridement of heavily contaminated or necrotic tissue Lavage... Large volumes, under pressure best Isotonic saline best Iodine 0.1% (1ml/l) Chlorhexidine 0.05% Higher concentrations inhibit healing

7 Skin Grafting Requires healthy, uninfected granulation bed. Pinch grafts are simple to perform but require sterility and good aftercare (bandaging) and control of infection

8 Suturing Simple interrupted often best Suture material selection Debride and flush Close dead space Tension relieving sutures if wound edges are likely to be under tension Drainage Primary/secondary wound healing

9 Harness sores are a cause of avoidable suffering. They are obviously extremely painful as well as attracting flies and consequent transmissible diseases eg EZL. Sarcoids etc It is important that the harness of an affected animal is inspected and adjustments made. Training of local people to make and and maintain safe comfortable harness will reduce suffering, limit disease transmission and enhance the working capacity of the animals.

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11 Dermatological Investigation Examine whole horse, dermatitis may be a manifestation of systemic disease eg photosensitisation in liver failure. Culture Bacteria, fungi etc Biopsy for histology Microsopy (onchocerca, demodex,sarcoptes,chorioptes)

12 Insects An important cause of poor welfare and loss of work capacity Irritation eg flies, lice, mange mites Allergy eg cullicoides (sweet itch) Disease transmission eg epizootic lymphangitis, trypanosomiasis, Parasites eg bots,onchocerca

13 Lice Damalinia equi chewing lice often on body Haematopinus asini Larger, sucking lice in mane and tail

14 Trombicula autumnalis harvest mite Irritation of lower limbs papules and wheals usually when grazing long grass in warm conditions Dermanyssus gallei red poultry mite Not a true horse parasite but very irritant if in horse s environment

15 Sweet itch Cullicoides midge Hypersensitivity Pruritis and self trauma (rubbing out hair, skin excoriation) particularly of the mane and tail Treatment: prevention by barriers: mesh blankets, thick ointments etc Corticosteroids will control the allergic response but have side effects (immunosupression, risk of causing laminitis etc )

16 Insect irritation and hypersensitivity can be avoided/limited by the use of environmental management (eg stabling), physical barriers( eg rugs, fly fringes etc, insect repellents and insecticides. Corticosteroids should only be used as a last resort.

17 Mange mites Demodex D equi body,d Caballi eyelids and muzzle In hair follicles Patchy alopoecia face, neck and shoulders Non pruritic Non infectious, present in small numbers in normal horses Clinical disease due to immune compromise

18 Mange mites Sarcoptes Head neck and shoulders Pruritic Treatment organophosphates? Ivermectin/moxidectin

19 Mange Mites Psoroptes Rare Thickly haired areas and ears Pruritic may cause head shaking Chorioptes Common in heavily feathered horses, legs. Very pruritic Treatment: Ivermectin, Moxidectin, Fipronil,OPs

20 Onchocerca Adults in ligaments, microfilaria in skin transmitted by flies. Some horses are hypersensitive and develop skin lesions

21 Habronemiasis Habronema draschia Stomach nematode,eggs transmitted by flies Conjunctival, lacrimal, and urethral process granuloma Wound granuloma Treatment ivermectin, doramectin etc

22 Strongyloides westeri Pruritic dermatitis of distal limbs of young foals (rare manifestation) Oxyuriasis Female worms in rectum lay eggs on perineal skin Anal pruritis, tail rubbing etc Resistant to ivermectin and related drugs treat with pyrantel repeat after 1 week

23 Dermatophilus An actinomycete whch causes an exudative dermatitis particularly in skin exposed to wet or unhygienic conditions Treatment... Keep animal in a clean dry environment Antibiotics KI per os 5% KMnO 4 topical

24 Abscesses Corynebacterium psuedotuberculosis Ulverative lymphangitis pectoral abscesses typical Spread by flies Treatment drain, antibiotics, KI Streptococcus Equi strangles Abscessation of lymph nodes usually submandibular and parotid, will burst to discharge pus, highly contageous

25 Staphylococcus dermatitis and folliculitis Painful exudative dermatitis Can be associated with dirty, ill fitting harness Treatment Antibiotics: penicillin

26 Scirrhous cord Bacterial pyogranuloma, complication of castration, requires surgical debridement and antibiotics.

27 Equine herpes virus (EHV 3) Coital exanthema, sexually transmitted. Vesicles and ulceration of skin of penis and vulva Self limiting, heals in a few weeks.

28 Surra Trypanosoma Evansii Tansmitted by flies Weight loss Anaemia Oedema Petechiae Paralysis

29 Dourine Trypanosoma Equiperdum Transmitted by mating Oedema of genital organs Neurological signs Oedema patches on skin Weight loss Abortion eventual death

30 Burkholderia Mallei Glanders zoonotic Ulcerating nodules respiratory tract, internal organs, skin. Suspected to be in Ethiopia

31 Untreated mortality 95% Donkeys more susceptible than horses Three forms Nasal Pyrexia, cough, thick green/yellow nasal discharge, crusting around nares, occular discharge nodules in nasal mucosa can be rapidly fatal Pulmonary Fever, dyspnoea, persistent cough, weightloss +/-diarrhoea +/-polyuria Cutaneous Insidious and chronic cough and lymphadenopathy, ulcerating cutaneous nodules with purulent discharge Diagnosis Mallein test, Smears, serology, PCR Treatment Antibiotics in endemic areas may lead to subclinical carriers Epidemiological control Suspected, not confirmed in Ethiopia, surveillance important

32 Histoplasmosis Epizootic lymphangitis 19% cart horses in Ethiopia Histoplasma capsulatum, fungus with yeast stage Discharging lymphangitis, ulceration, corded lymphatics Conjunctival and pulmonary form Transmitted by flies into wounds Drain wounds, flush with 4% iodine, Potassium iodide 10g/100kg/day daily for 5 days then every other day for 3-4 weeks Avoid harness sores, good wound care, fly protection

33 Epizootic lymphangitis Disease is more severe in horses than donkeys Lacrimal form commoner in donkeys

34 Cellulitis Staphylococcus/ anaerobes usually enter via a wound Very painful Ultrasound for synovial structure involvement, if none, treat with NSAIDS, antibiotics, exercise to promote lymphatic drainage.

35 Dermatophytosis ringworm Trichophyton ( equinum, verucossum, mentagrophytes) Microsporum ( equinum, canis) Mild self limiting, easily transmitted between horses by harness etc Spores very resistant in the environment Treament topical iodine/antifungals

36 Equine papilloma virus Common, usually on the muzzle/ears of young horses clinically insignificant, treatment unnecessary Equine pox viruses Mild self limiting

37 Melanoma in grey horses Very common in older grey horses usually on the dock, perineum, perioccular region or parotid area. Treatment usually not necessary

38 sarcoids nodular occult mixed verrucose

39 Sarcoids are common skin tumours of horses, they do not metastasise internally but can be very extensive and severe. Commonly found in the perioccular region on sheath, scrotum, thighs and axillae. Can present as occult lesions (thinning of hair), verrucose (warty) lesions, nodular and severe fibroblastic form, often occuring at the site of wounds. Treatments include topical cytotoxic cream application, surgery (can result in worsening of lesion... often inadvisable), immunotherapy (bcg injections in perioccular sarcoids), radiotherapy. Flies probably have a role in transmission. Avoid by protecting wounds from flies and avoiding harness sores.

40 Neoplastic skin conditions Squamous cell carcinoma 3 rd eyelid, palpebrae often in unpigmented skin Lymphosarcoma Mast cell tumour Fibroma

41 Cysts can occur anywhere on the skin a common site is the artheroma of the false nostril Calcinosis circumscripta (calcium deposition often near stifle)

42 Burns Treat smoke induced pulmonary oedema Limit fluid loss, wet dressings Treat hypovolaemic shock Antibiotics against secondary infection Dietary support alfalfa and oil

43 Photosensitisation Photodynamic agents directly ingested as plants Liver failure Fails to detoxify phylloerythrin resulting in photosensitisation, reddening blistering and sloughing of white skin. Senecio (ragwort) poisoning a common cause of chronic liver failure

44 Autoimmune skin disease Rare group of conditions manifesting as vesicles and crusting skin lesions and lesions at the mucocutaneous junctions, steroid therapy may help but prognosis is poor. Pemphigus MEED Lupus Alopoecia areata

45 Immune mediated vasculitis Purpura haemorrhagica can be a complication of strangles Oedema haemorrhages Pastern and cannon leucoclastic vasculitis

46 Urticaria Allergen induced wheals and plaques of oedema, usually resolve may need steroid treatment, adrenaline if associated with generalised anaphylaxis Contact Inhaled Ingested Administered drugs

47 Cushing s disease Older horses classically manifests as a long curly coat along with systemic signs (PU/PD, susceptibility to laminitis, fat redistribution etc

48 Therapy Antibiotics, long course often indicated Antifungals Enilconazole,Iodine (KI per os) Antiparasitics Ivermectin, doramectin, moxidectin Antinflammatories/immunosupressive Corticosteroids; dexamethasone, prednisolone PO Antihistamines limited efficacy in horses Insect barriers Wound dressings

49 Topical treatment Povidone iodine 0.1%-2% (4% EZL) Chlorhexidine 0.5%-0.5% Metronidazole for anaerobes Miconazole, enilconazole for fungi Corticosteroids Honey Fly control and barriers

50 Well fitting harness, grooming and fly control will prevent many skin lesions and consequent disease and loss of working capacity.