Sweet itch

Chafed tails and mane, horses fully wrapped up, dozens of remedies in the tack room… Summer eczema or sweet itch is an annoying condition for many horses, but also for their owners. Despite it occurring in many horses, there is no ideal cure available yet. There are various measures you can take, or resources that you can use, but it depends on each individual horse what works and what doesn’t. In this article we explain what sweet itch exactly is and what you can do to combat ‘the big itch’. 


Sweet itch is also called summer eczema. It is a condition that can cause a lot of itching in the horse, resulting in the horse rubbing. This can lead to broken hairs on the tail and mane or, in severe cases, severe abrasions or lesions on the tail and mane. 


The main cause of sweet itch is the bite of the female Culicoides midge (Culicoides Robertii). The midges generally only fly when the temperature is above 5 degrees Celsius. So they appear around April/May and disappear around October/November. Every horse is stung by this midge from time to time, but horses with sweet itch are allergic to it. These midges are mainly found near wetlands, without too much wind. The females use the horse’s blood to produce eggs. They choose the spots around the tail and mane, sometimes also the belly seam, to draw the blood, because the skin is softer here. Before they suck the blood, some saliva is released and it is the saliva that horses can have an allergic reaction to. In principle, any horse can suffer from sweet itch, but some breeds are more sensitive to this than others (such as Haflingers, Fjords, Friesians). Heredity also seems to influence whether or not sweet itch will development. In addition, a compromised immune system can cause the horse’s allergic reaction to be more severe. 


A lot of research is being done into the cause and treatment of sweet itch. For example, Wageningen University in the Netherlands has been conducting research for five years in collaboration with Utrecht University. This has brought them one step closer to methods for diagnosing, reducing and treating sweet itch. For example, they found that healthy horses had a different immune response than horses that are sensitive to sweet itch. The reaction of healthy horses helps against the development of the symptoms. In the tests, they looked for the allergens (specific proteins) in the saliva of the midge, so that they could use them to develop a blood test. With this blood test it can be shown in 9 out of 10 cases whether a horse has sweet itch. In addition, the allergens offer opportunities for developing a therapy so that the horse’s allergic reactions will be less severe. 


If a horse suffers from sweet itch, there are a number of things you can do. The midges are most active around sunrise and sunset. It can help to keep your horse inside during those hours. Sometimes horses are also stung in the stable. You can then choose to hang very fine mesh in front of the stable windows, so that the midges cannot (easily) come in. It may also help to hang a fan in the stable, as the midges do not like the wind. If the horse is turned out, a fly sheet can offer a solution. It is important that the neck and base of the tail are also well covered. These sheets are most effective if they are worn continuously before the midges are active, until they disappear again (from March to the end of October). If you start using a fly sheet while the horse is already itching, the effect will be less and the horse will continue to rub. In addition, putting your horse in an open, windy field can help. The midges will be less inclined to fly there. You can also make adjustments in your horse’s diet to potentially reduce the problem. Do not feed the horse too much concentrates and preferably feed a concentrate without molasses. Vitamins E and C provide a stimulate a good immune system and help remove toxins from the body. Minerals such as copper, manganese and zinc are important for a healthy skin. Research also shows that linseed oil can help to reduce itch.


There are all kinds of different remedies and products available that aim to reduce or prevent the symptoms of sweet itch. Whether the treatment works, and to what extent it works, depends very much on the individual horse. Often this is just a matter of trying it out. 


As it is in many cases, with sweet itch prevention is better than cure. So if you know that your horse suffers from sweet itch, it is wise to start preventative measures ahead of time, such as putting on a fly sheet. Does your horse already suffer from itching and/or rubbing abrasions? Then contact your vet to find the best solution. 



Leave a Reply