here - Australian College of Veterinary Scientists

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
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ACVSC Proceedings Dermatology Chapter Science Week 2005