Sweet itch is caused by an allergic reaction to the saliva of the Culicoides biting midge, writes equine vet Leona Bramall. Horses affected by sweet itch develop itching of the mane and tail and, in some cases, the face and poll. Itching begins in summer, but for some horses sweet itch can be a year-round problem. The level of severity varies. While some horses itch themselves bald, others may develop ulceration or secondary bacterial infections.

Preventing sweet itch is based on reducing exposure to the offending midges. If at all possible, avoid fields with stagnant water or those adjacent to woodland areas that inherently have high midge populations. Horses affected with sweet itch should be stabled at dawn and dusk when the midges are most active. Fans may deter midges from entering stables.

Sweet itch fly masks and fly rugs also play an integral role in prevention, as do fly and insect repellents, although the effectiveness of these varies.

When to call a vet

Contact your vet if your horse’s itching continues despite using the above preventative measures, if skin is hot and inflamed, or if you’re concerned about possible infection. Your vet will examine your horse and may prescribe injectable, oral and/or topical (cream) medications.

In addition to sweet itch, some horses can develop skin lumps (urticaria), with or without associated itching secondary to other flies and insects. Severity varies, from a small lump at the site of contact to an extensive hypersensitive response.

If your horse is stabled during the day, ensure his stable is kept as clean as possible to reduce the number of flies in the stable environment. You can also spray the stable with fly repellents, but don’t spray directly near water or feed buckets. If the lumps are extensive, don’t appear to be resolving, or make your horse itch, seek advice from your vet.

Early intervention is key

World Horse Welfare concurs that prevention is better than cure when it comes to sweet itch. The charity reminds horse owners that the condition starts before the summer months begin.

“One of the worst things you can do is ignore the early signs. If you suspect your horse is suffering from sweet itch, the first step is to try to stop your horse from getting bitten and then contact your vet for advice,” said a spokesperson for World Horse Welfare. “Grooming your horse regularly is a good way to keep a close eye on their skin so you can recognise any changes and take appropriate action quickly.”

Natural remedies for sweet itch

According to Hilary Page Self, medical herbalist and director of Hilton Herbs, there is research and anecdotal evidence to show that herbs can be used to help minimise the symptoms of sweet itch in horses. Useful herbs to consider include the following, but remember to consult your vet before making any sudden dietary changes.

Steamed linseed

Steamed linseed has been known to alter the fatty-acid profile of the horse’s hair and reduce irritation. Linseed is a rich source of the essential fatty acid, Alpha Linolenic Acid (ALA), and research suggests that foods rich in ALA could reduce inflammation and improve the clinical appearance of sweet itch.

Brewer’s yeast

Brewer’s yeast contains a range of B vitamins and amino acids that are said to help reduce the horse’s allergic response to the Culicoides midge. Brewer’s yeast also makes the blood unpalatable to midges and is vital for hair growth and the production of cell membranes.


Buckwheat contains high levels of flavonoids and anti-oxidants, such as quercetin, which acts like an anti-histamine and an anti-inflammatory.


Silica is a major component of hair so the rich silica content of diatomaceous earth is what helps stimulate hair growth, hair strength and hair quality.

Advice for feeding herbs

“Sweet itch is a very difficult condition to treat,” says Hilary. “Most horse owners end up managing the problem with a combination of things such as a midge rug, organising turnout to avoid peak midge times and topical products and feed supplements.

“Always bear in mind that just because a substance is deemed ‘natural’, it doesn’t mean it can be used excessively. Respect the instructions for use in the same way you would with conventional medication. Ensure that all herbal supplements and healthcare products are sourced from suppliers who can guarantee top-quality ingredients and expert formulations. These suppliers should be able to provide detailed information on product use and there’s a legal obligation on manufacturers to clearly state ingredients on the packaging.”

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