What causes sweet itch and how do I treat it?

What causes sweet itch and how do I treat it?

Sweet itch is caused by a sensitivity or allergy to the saliva of the Culicoides midge, which results in severe itchiness and skin irritation. Affected horses and ponies usually have characteristic lesions in their mane, along their back, and at their tail base, although most of the midge bites actually occur in the groin area and on the underside of the tummy.

Sweet itch treatment

Keeping out of the way of bites is the best way to avoid this condition, as none of the potential treatments is completely effective. This can be done by:

  • Stabling at dawn and dusk.
  • Using effective fly repellents (it is important to remember to apply these to the tummy and groin areas as well as elsewhere, since this is where most of the bites occur).
  • The use of a fly rug that protects the horse’s underside and neck is also advisable, because this helps to prevent the mites penetrating right down to the skin. It also helps to protect the horse from damaging itself by scratching.
What insects will affect my horse? Preventing fly-related problems

What insects will affect my horse? Preventing fly-related problems

A number of flies can cause problems In horses: these range from uncomfortable and infected bites, to distressed behaviour and headshaking, which in particular can seriously affect performance. In addition, blowflies will lay eggs in open wounds, and the maggots that hatch can then cause further damage.

Flies may also have a role to play in the transmission of sarcoids and they can also pass on the papilloma virus that causes warts. Culicoides midges are also problematic: they can cause severe skin irritation, particularly in those horses that have an allergy to their saliva, which can develop ‘sweet itch’. and mosquitoes can also cause nasty bites.

Ticks are a problem In some parts of the country, usually being transmitted on to the pasture by sheep or deer. They attach to the limbs of horses to suck blood, and can transmit infections; these include Lyme’s disease, which causes lethargy and arthritis.

Other insects that can cause disease include lice and mange, both of which are normally only transmitted directly from infested horses. It is therefore a good idea to isolate new arrivals, check them over carefully before they come into contact with other horses, and to put a double fence between different groups of horses to prevent contact over the fence. Any Signs of skin disease should be investigated promptly by a vet.

How to prevent fly problems

The problems caused by flies, midges, mosquitoes and ticks can all be prevented by being vigilant and dealing promptly with the situation with a number of measures.

Insect repellents

There are a variety of products on the market, the most effective of which are available from vets.

Herbal fly repellents

Particularly those containing citronella, can also be helpful, but may be less effective than those containing permethrin-based products.

‘Frontline’, a dog and cat flea product, is unlicensed for use in horses at this time, but is used successfully by many owners to prevent ticks and other parasites from causing problems, and some horse owners use cattle fly tags (also currently unlicensed in horses). These can be attached to the headcollar or mane, with good results.

Fly masks and fringes

Fly strips and fly traps

Can be used in stables but positioned well out of reach of the horse.

‘Sweet-itch’ rugs (that protect most of the body and neck)

Can be very useful.

Keep horses away from open water in the summertime

Pasture horses away from other species

Particularly cows, sheep and deer, which attract flies ans pass on ticks).

Remove muck promptly from areas near stables

Stable horses at dawn and dusk

This is when most of the flies and midges are about. Try turning them out at night rather than during the daytime in the summer months.

Skin lumps on your horses back?

Skin lumps on your horses back?

Skin lumps on a horse’s back can occur for a number of reasons.

An ill-fitting saddle is a common problem and, quite apart from saddle sores, can result in the development of small, hard lumps of fibrous tissue in the saddle area.

Fly bites and irritation due to midges are other common problems, and can cause swellings and nodules to develop, as can the aberrant migration of some intestinal parasites.

Finally a number of types of skin tumour can develop, which may also have a similar appearance. Skin tumours ranging from melanomas (particularly common in grey horses) to squamous cell carcinomas can also appear elsewhere on other parts of the body.


  • As long as small skin lumps cause few problems, leaving them alone may be an option.
  • However, lumps that grow rapidly, or that cause pain or sensitivity when touched, may need to be either biopsied or removed, and this treatment may necessitate several weeks off work while the wounds are healing.
  • Where masses on the back are concerned, it is also important to make sure that tack is a good fit, and that the skin circulation to affection areas is optimised by using a gel pad or foam pad under the saddle to reduce the pressure in the area: massage may also be helpful.