Queensland Itch Remedies
that may make a difference. I understand the distress and frustration with watching a horse mercilessly self mutilate.
The only way to beat Queensland Itch is to live in a place that doesn’t have midges (Culicoides species). Sadly, it isn’t always possible to move away from the coast to a drier environment that doesn’t support the midge’s favourite habitat. Queensland itch or sweet itch is more correctly known as Recurrent Seasonal Pruritus.
A vet explained to me many years ago that horses will rub themselves where they can, not necessarily where they are actually bitten. So if a horse is rubbing his head raw, the bites can be all over his body, the horse won’t be getting bitten just at the head. Studies show that the majority of bites are along the topline region.
Unfortunately midges live and breed in still water, mud and wet grass, even manure, making it impossible to eradicate their favoured habitat.
An allergy is an exaggerated and imbalanced immune system response to something in the environment that normally shouldn’t cause any detectable response. Queensland Itch, also known as ‘Sweet Itch’ is an allergic response to proteins in the saliva the midge inserts when it feeds, resulting in the skin becoming inflamed all over the body. So inflamed that a change of wind direction, a mosquito, anything can set the poor horse off itching. If you have ever owned a dog with flea allergy dermatitis then you’ll know that the pooch doesn’t need fleas to continue scratching. It can take 2 to 6 weeks for the inflammation to subside.
For more detail on the science behind the allergic reaction occurs check out Dr Carl Eden’s BVM S MRCVS description, link at bottom of page.
Treatments consist of either keeping midges away or soothing the inflammation, especially where the horse is actively rubbing.
Keeping midges away:
Keeping midges away:
Combination of soothing and a repellent/barrier to midges:
Some vets recommend drug treatment involving corticosteroids, this is my least favourite option. A vet explained to me that not all horses respond to drug treatment, some need multiple doses throughout the itch season and these drugs can have nasty side effects and it can be expensive. Never attempt with any horse that is insulin resistant, IR.
Internally the best approach is a more than adequate nutrient diet and minerals in the right proportions. This can make a difference by making sure our horses are provided with the correct level of nutrients which allows the immune system to produce counterbalancing responses.
Other options – feeding:
A combination of chondroitin sulfate, spirulina and ground linseed has been very effective for a number of itch horses.
I’ve seen a lot of remedies recommended for Queensland Itch that do not work, mainly because there is nothing in it that deals with either soothing or reducing the inflammation or preventing the midges from biting. If you have a remedy that you are pretty sure does work I’d be interested in hearing about it.
Some people recommend the active worming ingredient ivermectin to be applied regularly along horse’s topline but they are mistaken, ivermectin has nothing to do with Queensland Itch or midges, it deals with a worm called Onchocerca (neck threadworms) that can cause similar symptoms as Queensland Itch. These worms are so tiny, the midges are a carrier for them in their saliva. For me, that is incredible and even more reason to hate midges! The stage carried by the midge is late larval and travels to the nuchal ligament in the horse’s neck. The stage that sets up house in the ventral midline and causes belly irritation is early larval and is coming from adults in the neck. Adults in the nuchal ligament of the neck can also cause irritation and make the horse rub. The adults live for about 5 years, producing microfilaria all that time but higher levels in the warm months. When they die, calcified nodules eventually form. Fortunately ivermectin and moxidectin can kill the microflaria though it does depend on drug resistance in your area. Horses infected with Onchocerca generaly scratch along their manes and bellies but not the tails. Both the online Merck Veterinary Manual and world leading parasitologist Dr Martin Nielsen has excellent information on Onchocerca, see links below.
Links may change over time. If a link doesn’t work, search the title in your search engine.
Equine Cushings and Insulin Resistance discussion group. Dr Eleanor Kellon VMD oversees.
Dr Carl Eden’s BVM S MRCVS Queensland Itch
Herd RP and Donham JC (1983) Efficacy of ivermectin against Onchocerca cervicalis microfilarial dermatitis in horses Am. J. Vet. Res. Jun;44(6):1102-1105
Dr Eleanor Kellon VMD (2008) Horse Journal Guide to Equine Supplements and Neutraceuticals The Lyons Press, Guildford, Connecticut
Dr Eleanor Kellon VMD Nutrition and the Therapy course
Merck Veterinary Manual – search for Onchocerciasis
O’Neill W, McKee S and Clarke A.F (2002) Flaxseed (Linum usitatissimum) supplementation associated with reduced skin test lesional area in horses with Culicoides hypersensitivity Can. J. Vet. Res. Oct;66(4):272-277
Dr Martin Nielsen
The Parasite Journey of the Horse Episode 1 Threadworms