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cutaneous vasculitis can be difficult to obtain, and similarly to other dynamic disease processes, multiple and repeat biopsies may be needed to confirm a diagnosis. Treatment Aggressive treatment for cutaneous vasculitis is indicated in severe disease to prevent extensive ulceration and limit tissue damage and scarring. Glucocorticoids are the cornerstone of therapy for severe cutaneous vasculitis in humans, with prednisolone considered the most reliable medication for reducing lesions and halting progression of disease. Similarly, prednisolone is widely used for treatment of equine cutaneous vasculitis, with oral doses of 2-4mg/kg once daily reported successful. In more recalcitrant cases, dexamethasone 0.2-0.4mg/kg once daily may be more effective at inducing response. Daily induction doses should be continued until the disease is in clinical remission and then gradually reduced, with alternate day dosing commenced as soon as possible. With severe or slowly responsive cases, reduction in dose by 25% of the 48-hour dose per 10-14 days has been recommended to help limit relapse. Such high-dose glucocorticoid therapy should ideally be instituted concurrently with a management plan to minimise the risk of laminitis, as glucocorticoids, in particular triamcinolone or dexamethasone have been linked to an increased risk of this debilitating disease. Low energy diets, weight control, and regular gentle exercise are strongly recommended. In the acute stages of cutaneous vasculitis supportive care including hydrotherapy, walking and good skin hygiene can also be helpful. The clinical course of cutaneous vasculitis in any patient is difficult to predict, with some cases resolving completely within a few weeks, and others becoming chronic or recurrent. It is important to search thoroughly for underlying aetiological factors, especially in severe, chronic or recurrent cases, and treat promptly wherever possible. Minimising factors likely to exacerbate vasculitis, such as excessive stress, heat or cold exposure is also proposed of help with human disease. The use of alternative immunomodulating drugs to glucocorticoids for equine cutaneous vasculitis appears unreported, however a range of other drugs have been used in human disease. For treatment of severe, chronic, or poorly responsive cutaneous vasculitis in humans, azathioprine, cyclophosphamide, methotrexate, or mycophenolate mofetil have been recommended. Little or no information is available on the use of these drugs in the horse, however expense likely limits their use regardless. For subacute and chronic disease in humans, drugs including colchicine, dapsone, sulphasalazine, and antimalarial agents can be effective alternatives or additions to prednisolone. Colchicine and dapsone primarily inhibit neutrophil chemotaxis and activation, so are theoretically most likely to be effective in neutrophilic vasculitis. Dapsone or sulphasalazine are reported to be effective steroid-sparing options in some forms of canine cutaneous vasculitis. The author has used Dapsone in one horse with initial urticaria progressing to purpura haemorrhagica syndrome, at a dose of 1mg/kg twice daily for over 4 weeks concurrently with prednisolone. There was apparent poor response, with continued rapid relapse on attempts to lower prednisolone dosage. In cutaneous vasculitis in humans caused primarily by thrombosis some further 114 ACVSC Proceedings Dermatology Chapter Science Week 2005
treatment options have been used. Pentoxifylline, that modifies plasticity of red blood cells allowing easier passage through narrowed vessel lumina, along with a myriad of inhibitory effects on cytokines, leukocytes and endothelial cells, is an apparently safe and well-tolerated option with efficacy in both human and canine disease, although a lag phase of weeks to months to see beneficial effects is apparent in humans. Low-dose aspirin, anabolic steroids, anticoagulants, and niacinamide/tetracycline combinations have also been used. In summary, for acute cutaneous vasculitis in the horse, rapid treatment with prednisolone at immunosuppressive doses is currently the recommended treatment option. A search for underlying aetiological factors is vital, and a concurrent management plan to minimise risks of laminitis prudent, along with general supportive and wound care to help limit the debilitation of severe disease. For recalcitrant or recurrent cases with poor response or glucocorticoid side-effects, alternative options remain speculative, with little information available on efficacy or safety. More potent glucocorticoids such as dexamethasone or triamcinolone may be used to help induce remission in severe cases. Dapsone has been used in a steroidsparing role in at least one horse without evidence of benefit at the doses and duration chosen, but also without apparent adverse effects, and it may be used as a treatment option for poorly responsive or subacute disease. Screening for adverse haematopoietic or liver effects, which have been reported in humans with the use of this drug, may be indicated. Pentoxifylline has been used safely in the horse, and could similarly be considered for poorly responsive or subacute disease, especially if there is histological evidence of vessel thrombosis in the face of minimal inflammation. Gold salts are another option to consider for recalcitrant disease and have been used effectively and safely in horses with pemphigus foliaceus and some other immune-mediated diseases, although their use in equine vasculitis appears unreported, and they are not a recognised treatment option for cutaneous vasculitis in humans. References Equine Dermatology. Scott DW. WB Saunders, St. Louis, Mo. 2003: 522-546. Cutaneous Vasculitis Update. Gibson LE. Dermatologic Clinics 2001:19;4:603-615. Purpura haemorrhagica in 53 horses. Pusterla N, Watson JL, Affolter VK et al. Veterinary Record 2003. 153: 4, 118-121. ACVSC Proceedings Dermatology Chapter Science Week 2005 115
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Australian College of Veterinary Sc
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Australian College of Veterinary Sc
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3.00 Afternoon tea 3.30 How I treat
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Dr Jennifer A. Charles BVSc MVS Dip
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Scientists in Feline Medicine in 19
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IgE-bearing cells have been demonst
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years, median age 6.5 years, with a
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dusts, grain smuts, moulds, danders
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References: Evans AG, Paradis MR, &
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Comparatively simple, cheap and eff
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TABLE 1: CURRENT ALLERGENS SELECTED
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AmericanCockroach Cockroach mix
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Patient Preparation Drug Withdrawal
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Each injection site is visually exa
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References 1. Scott DW, Miller WH:
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Intradermal Testing (IDT) in Horses
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TABLE 2 Additional allergens used i
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Allergen Positive reactions Mosquit
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much higher and corresponded to the
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and this and other uncontrolled tri
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Introduction Diagnostic Approach to
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Wheals vary in size and shape and q
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References Evans AG, Paradis MR & O
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Introduction: Equine Chronic Urtica
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Acute treatment - Epinephrine 1:100
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anecdotal success with use of human
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an 80:20 mixture of evening primros
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Clinical approach to the horse with
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identify plants in a pasture that m
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Equine sarcoidosis Sonya Bettenay T
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described as a possible feature of
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Page 67 and 68: Introduction The equine sarcoid: an
Page 69 and 70: Clinical Presentation Small fibrous
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Page 79 and 80: any anatomic location but commonly
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Page 101 and 102: Diagnosis History of access of hors
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