Sweet Itch

Taking the scratch out of Sweet Itch

By Wendy Talbot on 29 May 2018

Despite having some amazing protective properties, the horse’s skin isn’t infallible and, as with humans, it is vulnerable to damage, disease and allergies. During warmer weather Sweet Itch is a common bugbear, with unrelenting itching causing some horses to self-harm.

But why are some horses affected and not others if they are all living in the same environment? Let’s take a look at the causes, signs and prevention of this irritating condition so that you can help take the scratch out of your horse’s itch.

What causes Sweet Itch?

The main cause of sweet itch is a biting midge and quite simply some horses develop a hypersensitivity to the saliva the midge releases when it bites. There is good evidence that some horses are genetically predisposed to the condition with Icelandic ponies, Shire horses, Welsh and Shetland Ponies, Arabs, Connemaras, Friesians, Warmbloods and Quarter Horses recognised as being at increased risk.

The hypersensitivity causes persistent itching and the horse will rub, bite and scratch to try and relieve the irritation. A single exposure to biting midges may cause a horse to itch for around three weeks so prevention is key.

Sweet Itch

How can I spot the signs of Sweet Itch?

Signs of sweet itch are usually easy to spot:

  • Chronic itching which usually shows a strong seasonal tendency (worse in April to October)
  • Hair loss and bald patches, especially on the mane and base of tail, caused by rubbing
  • Crusty or broken skin or open, bleeding sores, caused by attempts to alleviate the itching
  • It is important to speak to your vet to obtain a correct diagnosis and to rule out any other conditions which may cause similar signs

Twelve ways to stop the itch

  • Midges are often worse at dawn and dusk so try and keep your horse in a cool, dark stable at these times of day
  • Invest in a well-fitting fly rug that also covers the neck, belly and base of tail
  • Midges can attack faces and forelocks too so using a properly fitting face mask can be of benefit
  • Use a good fly repellent or insecticide spray to keep the culprits at bay
  • Emollient shampoos and lotions can help bring relief to irritated areas
  • Cold hosing or the application of cold packs can bring temporary relief 
  • Keep susceptible horses away from wet areas which are breeding grounds for midges
  • Keep your yard, stables and fields clean to detract insects
  • Be prepared and start your Sweet Itch prevention programme before the flies really take hold
  • Check your horse thoroughly every day to spot any warning signs of itching
  • Speak to your vet about prescription treatments that may be appropriate for your horse 
  • If all else fails sometimes moving the horse to a different area with less midges should be considered

Did you know?

  • Just like humans, the skin is the largest organ of the body for the horse and can account for 12-14% of overall weight. 
  • An insecticide aims to kill the fly as soon as possible after contact with no biting needed. For maximum effectiveness treatment should be started before the fly season has begun, to control breeding, and continued at regular intervals throughout the season. 








Wendy graduated from Bristol University in 1999. She then went on to complete a residency at Liverpool University and holds a European Diploma in Equine Internal Medicine. After working in practice for 13 years, she joined Zoetis in 2012 as the National Equine Veterinary Manager.

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