How To Prevent Sweet Itch In Horses

Let’s be honest nobody likes being bitten by midges and while most of the time it’s just irritating it can, in some horses, lead to sweet itch. Sometimes refer to as summer itch its proper name is Culicoides Hypersensitivity (due to the Culicoides midge that causes it) and can effect thousands of horses around the world every year. Rather like hay fever, once your horse has starts to suffer from it it’s very difficult to completely stop it, for this reason it’s better to prevent the flies from biting instead of treating the bites after.

What causes sweet itch?

Sweet itch is the result of a horse suffering a severe allergic reaction after being bitten by a midge from the Culicoides family (sometimes called biting midges) which is made up of over 5,000 species worldwide. More specifically it’s the proteins in the saliva that produce the allergic reaction in horses.

How do I know when my horse is suffering from sweet itch?

Most horses suffer around their head, mane, tail and along their dorsal midline but your horse can show signs of a reaction anywhere on their body. At the site of the bite your horse will start to develop lesions that are extremely itchy. In an attempt to alleviate the itching a horse will rub the area so much that not only will they create bald patches but they can even rub the skin raw until it starts to weep and bleed. If this happens you’ll need to make sure your horse doesn’t succumb to a secondary infection and teat that accordingly if he does.

Is sweet itch contagious to other horses and people?

Sweet itch isn’t at all contagious to other horses, nor to people. This is because it’s a reaction rather than a virus or infection. That said though it’s easy to understand why some people might think it is contagious because in areas with a high number of Culicoides midges a large number of horses are likely to be bitten which will naturally increase the number that suffer from the condition.

How can I prevent my horse from getting sweet itch?

As they say prevention is better than cure and in the case of sweet itch this is very true. If you live in an area with a large population of Culicoides midges it can be very difficult to prevent every single one from biting your horse. Unless of cause you cover your horse from head to toe in repellent and wrap him in protective netting, and let’s be honest no horse is going to thank you for doing that – even if you do have his best interests at heart!

That said with the vast majority of horses it’s the number of bites rather than just a single bite so you want to do everything you can to reduce your horse’s exposure to the midges. It’s important that you start your prevention plan before the start of the season.

  • Midges like to use standing and stagnant water and rotting vegetation to breed so keep this to a minimum around the stables. Make sure all water bowls and troughs have fresh water in them – your horse isn’t going to want to drink stale water so it’s important for that reason too. 
  • If your fields are particularly marshy you should either keep your horse away from them or, if possible, consider draining the fields.
  • Introduce a garlic supplement to your horses feed. This will cause your horse’s sweat to smell and taste of garlic which midges don’t like. It’s a strong smell that will stop a large number of midges from ever landing your horse. You can use fresh garlic but it’s important to speak to the vet before hand because fresh garlic contains N-propyl disulphide which can cause anaemia in horses
  • Stable your horse overnight during the summer. Midges prefer to feed at dusk and dawn but can also feed right through the night. Stabling your horse during these hours will greatly reduce his risk of being bitten. If you’re not able to stable your horse then make sure there’s no stagnant water around the paddock and keep your horse rugged up. A hood and fly mask will also help.
  • Placing mosquito nets across the stable door and windows will also help to stop any stray midges from biting your horse during the night.
  • Keeping your horse rugged up with a hood and fly mask will drastically reduce the area that a midge can bite. The right rug will only leave the legs exposed which are less lightly to be bitten, if a midge does land on your horses leg though it’s easier for him to remove it from there than it is for him to remove them from his neck.
  • Using a regular fly repellent (like Citronella oil) or mild insecticide (such as Benzyl benzoate) won’t get rid of the midges but will reduce the chances of them biting your horse in the first place. They mustn’t be used on broken skin and should be used daily for them to have a real benefit.
  • Applying an oily lotion (such as Vasoline) daily to your horse’s entire body will create a literal barrier to the insects bite.

How do I treat sweet itch?

It can be very difficult to completely treat sweet itch once your horse has started to develop legions but the key to successfully doing so is to start any treatments as soon as you notice the first signs. There’s a wide range of things you can do to treat it and most people find that a mixture of things work best. As a rule the treatments fall into one of two categories:

  1. Natural treatments – Some people find that using alternative solutions such as herbal remedies can be effective at reducing your horse’s suffering. As with humans things like aloe vera, lavender oil and wild geranium will help to reduce the itching, washing your horse with a mild hypoallergenic shampoo every few weeks can also help. While sulfur based products can also be used, they emit an odour that the midges find extremely unpleasant making it less likely for them to continue to bite.
  2. Medical treatments – If you find that using natural treatments isn’t helping enough then you may want to ask the vet to prescribe either antihistamines or corticosteroids. Antihistamines are the preferred option as they can be taken long term whereas horses who take corticosteroids, which contains steroids, long term are at a greater risk of things such as laminitis.

Dealing with sweet itch long term.

It can be stressful and difficult dealing with a horse that suffers from sweet itch, not only does it take time and money but it does also take a lot of effort on the owner’s/groom’s part. It can obviously be extremely stressful for the horse who is suffering too, they’re be in a great deal of discomfort and may become, understandably so, irritable and bad-tempered.

If you follow a careful management and prevention plan, such as stabling your horse and night and keeping him rugged up, then your horse will hopefully only suffer mild irritation. If you can move your horse to an area where there’s less midges that will help a great deal too.

Sadly sweet itch does tend to get worse year on year so finding a coping solution for both you and your horse is crucially important. During the summer months the horse’s sores can be so painful it can make him unridable. 

Is there a test to find out if a horse is susceptible to sweet itch?

Culicoides midge

Many vets will carry out an allergy test (sometimes called a patch test) to see if a horse is likely to suffer an allergy to a number of different things, including Culicoides midges. While this test isn’t 100% definitive it certainly is a good indication as to your horse’s propensity to suffer from sweet itch.

Some people don’t have the time or money, or don’t want the worry and stress of having to dealing with a horse that’s prone to sweet itch so this test can be very helpful for them.