here - Australian College of Veterinary Scientists

signs antihistamines (hydroxyzine hydrochloride at an initial dose of 300 mg twice
daily) were given by mouth or oral prednisolone at a dose rate of 1 mg/kg initially
daily, reducing to alternate day therapy.
Follow-up information was obtained for all except one case. Two horses died shortly
after referral before any response to management alterations could be assessed.
Progress reports were obtained initially one and three months after referral and
subsequently at various intervals for up to four years. All cases improved
considerably after management alterations that were recommended on the basis of
the history and positive skin test reactions had been implemented. Drug therapy was
necessary in only six cases. In four cases oral antihistamines were employed
intermittently when the pruritus or urticaria were severe, often coincident with
pollination times. A fifth was treated with antihistamines initially, but therapy was no
longer required after a major change of management. Low dose steroid therapy was
given to the sixth case initially, due to the severity of the urticaria and angioedema.
Major management changes were not possible and this horse required ongoing
intermittent administration of antihistamines because of recurrent urticaria, although
he remained asymptomatic most of the time. The respiratory problem in this case
has also persisted and worsened.
The author has used immunotherapy in only a handful of cases, where it has been
felt to be of benefit, but the results of management modification are usually
sufficient to control the problem sufficiently that clients rarely request
immunotherapy.
References:
Craig JM et al (1997) A double-blind placebo-controlled trial of an evening primrose
and fish oil combination versus hydrogenated coconut oil in the management of
recurrent seasonal pruritus in horses. Veterinary Dermatology 8, 177
Fiberg CA & Logas D. (1999) Treatment of Culicoides hypersensitive horses with
high-dose N-3 fatty acids: a double-blinded crossover study. Veterinary Dermatology 10,
117.
Littlewood JD, Paterson S, & Shaw SC. (1998) Atopy-like skin disease in the horse.
Advances in Veterinary Dermatology 3, p563
O'Neill W, McKee S & Clarke AF (2002) Flaxseed (Linum usitatissimum)
supplementation associated with reduced skin test lesional area in horses with
Culicoides hypersensitivity. Canadian Journal of Veterinary Research 66, 272-7
54
ACVSC Proceedings Dermatology Chapter Science Week 2005