What is Sweet Itch?

What is sweet itch

Sweet Itch is an irritating and sometimes painful condition that affects horses in the hotter months of the year. Theoretically, any breed can fall prey to it, however it tends to be more common in cobs more than in Arabs, thoroughbreds and other warm-blooded, non-native breeds. Alternative names for it include IBH (Insect Bite Hypersensitivity), Queensland Itch, Equine Summer Itch, and SSRD (Summer Seasonal Recurrent Dermatitis).

What causes Sweet Itch?

Sweet Itch is an allergic reaction to the saliva in the bite of midges (Culicoides Fly). Most horses are unaffected by the bite and will not display an allergic reaction. However, those that are allergic react to the allergenic compounds that are found in the saliva of the midge. Sadly, it's not yet known precisely which compound causes the reaction, or if it varies from case to case.

What time of the year does it occur?

Sweet Itch is generally only seen when midges are out in significant numbers, such as in the spring and summer, and sometimes into the autumn. In winter, midges are usually dormant. However, in severe cases, midge attacks in the autumn can continue to cause the symptoms for many weeks.

What are the symptoms?

The first symptom that you’ll notice is severe itching and rubbing of the affected area of the skin. Then painful looking lesions or sores develop in the places that have been rubbed. Sweet Itch is not contagious.

What does Sweet Itch look like?

The photographs below show what this condition looks like.

Sweet Itch On The Neck   Sweet Itch On The Tail

What areas of the horse are affected?

The most common place that the horse rubs are the crest of the mane and the top of the tail. Alternatively, you might see patches along the spine and around the head and ears. Do remember though, it can actually affect any area of the body.

What’s the best way to prevent it?

Sweet Itch is one of the most difficult skin conditions to control and, unfortunately, there’s no cure for it. It’s almost impossible to reverse an allergic reaction once a horse has been bitten. So, before you contemplate splashing out on potions, the best approach is to prevent or minimise the chances of the midges biting in the first place. Once a horse develops the allergy, it can get worse year on year. So the horse’s comfort and well-being are down to the owner’s management, which requires no financial outlay…

  • Avoid turning out or riding in areas where there is still or stagnant water, as midges thrive in this environment. Avoid hacking in woodland areas too, as these are also usually full of midges.
  • Ride and turn out on blustery days, as midges cannot remain airborne in winds above 5mph. You’ll probably find that your horse is more affected on still days.
  • Keep your horse in his stable in the evenings between 4pm and 9pm, as this is when the midges are most active. This can help to reduce the severity of an attack or prevent it altogether.

Need to treat sweet itch?

Read my other blog on how to treat sweet itch and find out more about the myriad of products that are available nowadays.

How to treat sweet itch


Kim Horton

Co-Founder of EQUUS and a keen equestrian, when Kim's not at her desk she's with her horse, Waldo.


  • Juliana Bergman-Burnside posted on April 27 2019 at 04:04 PM

    Fantastic and informative article as always.
    Thank you

  • Julia Snook posted on July 04 2019 at 04:07 PM

    I have had 2 horses with Sweet itch but thanks to the amazing rugs and supplements now available, it is no longer the huge problem it used to be! An absolute must, I have found is not to let my horse get bitten in the first place. Which means that she always has a rug with neck cover on from dusk til dawn and on what I call midgy days-muggy, still and thundery! I actually found that stabling them gave them something to itch on-creating the itch scratch cycle. My other must have is the horses’ skin in excellent condition-dry, scurfy skin is itchy. People don’t believe my mare suffers from sweet itch-so much so that on a recent trip to the vets, despite my warnings, they left her fly rug off overnight and in the morning, to their, horror, she’d practically scalped herself! Having had horses for over 50 years I would say that Sweet itch and head shaking-of which I have both, need no longer fill us horse owners with dread!

  • Jennifer Nicol posted on March 27 2020 at 10:03 PM

    From beginning of February I feed a supplement called Cavalesse. You don’t need a prescription from the vet for it. It reduces the amount of histamine that the horse produces so any adverse reaction to being bitten is reduced. It really helps. I would recommend it.


Leave a comment