Press room

2010 press releases

Posted: 04/03/10

Sweet Itch

Sweet itch affects between three and five percent of horses in the UK with the first signs visually appearing in the spring. Here we take a look at some of the alternative treatments available and Petplan Equine Vet of the Year, Gil Riley, gives us his thoughts as to their effectiveness.

Sweet itch (Summer Seasonal Recurrent Dermatitis), is caused by an allergic reaction to the saliva of a species of midge called Culicoides and starts to appear in the spring as the weather warms up. Some horses are more susceptible than others and the problem can be hereditary, hence its prevalence in some breeds more than in others. Icelandic and Welsh ponies, for example, have a higher incidence of the condition. Horses and ponies affected by sweet itch constantly rub their mane and rump causing it to become inflamed and the hair to fall out.

In the UK sweet itch is classified as a recordable condition and must be disclosed by an owner to a prospective buyer. Anyone buying a horse in winter needs to be particularly vigilant about checking for signs of sweet itch by looking carefully at the mane and tail for signs of hair loss of scurf. When a horse is vetted the condition can be considered as seriously as unsoundness would be, and many vets will warn a buyer off a horse with sweet itch. This in turn has insurance implications as the majority of insurance companies will not insure a horse for conditions the horse already suffers from. Therefore it is important to be aware if you choose to buy a horse with sweet itch you will have to pay the bills to treat it. Of course if it develops the condition post purchase then it will likely be among the conditions covered under your policy.

To prevent sweet itch, horses must be kept away from areas where midges will thrive such as muck heaps, rotting vegetation, near cattle and in wet boggy areas. Stabling during the peak feeding times of the insects at dusk and dawn can also help. However, once the problem manifests itself treatment can become more complicated and it is always a good idea to seek advice from your vet.

Below are a number of the more alternative ways of treating the problem with advice from Gil as to how effective they may be.

  1. Using Frontline on a horse’s mane and tail once a month during the spring and summer is thought to deter the midges and prevent them from biting horses in the first place. Frontline is designed to keep fleas away from dogs but can it help with horses?

    Gil says:
    “Frontline can be very helpful in horses but it is more usually applied as a treatment for the feather mite (Choriotes) which causes horses to rub their hind limbs and stamp their hind feet repeatedly. The difficulty with sweet itch is that for a chosen treatment to be successful, it has to prevent the fly biting as it is the reaction to the saliva in the bite that causes the problem. A product killing a fly after it has bitten, as Frontline tends to do, may not help as by this time the saliva will have been injected into your horse’s skin and there unfortunately will be plenty of flies to take the dead one’s place!”

  2. Calamine lotion is traditionally used on humans who suffer from irritated skin but some believe it can help sooth the discomfort felt by horses suffering from sweet itch. Is there anything in calamine that could cause a problem for horses?

    Gil says:
    “In my experience calamine lotion is well tolerated by horses and can be helpful in decreasing the distress felt by horses suffering from the condition. However, it is a treatment and not prevention i.e. it will not stop the flies biting.”

  3. Benzyl Benzoate is an insecticide originally used to treat scabies in humans. Its most recent use has been to treat sweet itch being thoroughly worked into affected areas on a daily basis, not however if the skin is broken.

    Gil says:
    “Probably the most widely used treatment for sweet itch. There is no doubt that it can be very helpful, especially in those horses and ponies that are either less sensitive or have been exposed to fewer bites. It is especially useful in those cases that are caught early i.e. before the skin is broken and bleeding. Using it in addition to management changes that minimize exposure to the biting midge can often be very successful”

  4. Human midge repellent is another popular way used to keep the midges away from horses and owners apply the lotion/ spray on a daily basis. Are there any immediate dangers using a product designed for humans and are there any substances that should be particularly avoided?

    Gil says:
    ”By all means give them a try - if they are safe for humans as a rule of thumb they will be safe for horses. Oddly, the most effective human preparation seems to be not a fly repellent but a hand cream, Avon Skin so Soft - it is allegedly bought by the British Army to prevent our soldiers being tormented by flies and if it’s good enough for our boys, it is certainly good enough for our horses and ponies! Always use a test area to check for any reaction before using on affected areas”

  5. The Boett Blanket was invented in Sweden and is made of a mesh that midges are not supposed to be able to bite through. It is put on horses when they go out in the field but does it really help keep the midges at bay?

    Gil says:
    “YES!!!! The best way to stop a reaction to a fly bite is to stop the fly biting! This is what the Boett rug does and this is an absolute MUST HAVE for anyone that has a horse or pony that suffers from sweet itch. There are many fly protection rugs on the market but unfortunately, like most things in life, you get what you pay for and you will have to invest upwards of £200 to get a rug that does what it actually says on the tin. Barrier rugs must be first put on your horse before the sweet itch season starts- putting them on after your horse has started itching is likely to lead to the rug being ripped to shreds and you therefore throwing away your hard earned money! Also remember that the rug must be worn every minute of your horse being outdoors- if the rug isn’t on, it can’t protect your horse!”

  6. Some owners believe that by adding cider vinegar to their horse’s feed once a day the midges will not bite in the first place.

    Gil says:
    “Many of my owners use it but unfortunately I’ve never seen evidence that it works. It won’t do any harm so by all means give it a go and you may be pleasantly surprised but I think it is fair to say results are at best unconvincing. I think it takes a lot more than a little acid to put these horrible flies off your horse!”

  7. A scoop of garlic powder is also believed to ward off unwanted midges and thus help prevent the sweet itch occurring.

    Gil says:
    “Garlic has many health benefitting properties and is certainly a good supplement to give a horse or pony for many reasons but I’m afraid in my experience sweet itch isn’t one of them. Give it to your horse for its potent anti-oxidant qualities though!”


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