Sweet Itch


Summer Seasonal Recurrent Dermatitis – Sweet Itch Sweet itch can be an irritating problem for your horse throughout the spring and summer, but there is a lot you can do to alleviate their distress. Sweet itch is an allergic skin disease, characterised by the horse continually rubbing its mane and tail. The hair is broken or lost and the skin becomes thickened, discoloured and ridged. The tail becomes moth eaten. There is often a crusty exudate. The horse has become allergic to the saliva in the bite of a particular midge, Culicoides. Once bitten, the horse will develop an allergic reaction at that site.

Because of the life cycle of the midge, sweet itch is a seasonal occurrence, from April to October. Some horses are not bothered, some show mild symptoms and some can have a severe reaction. The horse may be restless, swish its tail to deter flies and rub up against trees or fences.

There are many different species of Culicoides midge: they each have a different preference for the area of the horse they attack. The types that go for the head neck and tail are commonest; those that feed on ventral surfaces such as the belly are less common.

The lesions will heal over winter, but recur again next spring.


  • Decrease exposure to the midges: The midges are only on the wing for a few hours each day – early morning and early evening. Stabling the horse during these periods of risk will reduce the attacks. Use fine mesh screens within the stable to make them insect proof. A fan within the stable will create a breeze that will deter the midges from landing on the horse. There are fine mesh sheets and hoods that the horse can be rugged with when turned out. The midges breed around damp places and only fly a few hundred yards, so moving horses further away will reduce exposure. The pasture drainage may be improved, and the water trough inspected to reduce fly breeding.
  • Insecticide: There are lots of insecticides on the market that can help in alleviating the signs of sweet itch. Insecticides with Pyrethrins (originated from chrysanthemums) are the most effective treatment. Treatment may need to be applied every week in severe cases, and we would recommend “Switch™” as a pour-on treatment.
  • Repellents such as benzyl benzoate will keep the midges at bay but need to be constantly reapplied. Citronella is also partially effective. 
  • Treatment against allergy. Corticosteroids are the most useful product for treating allergic dermatitis. However they simply suppress the desire to scratch so the skin has time to heal, and do not cure it. They can have potentially serious side effects as well, and need to be used under veterinary supervision. Antihistamines are too short acting in the horse to be of benefit. Homeopathic treatment may also help to resolve the problem.


Further resource      



This information is provided for information purposes to our registered clients. It is the individual opinion of veterinary surgeons within the practice. It should not be relied upon as an alternative to a clinical examination and diagnosis by a veterinary surgeon. If in any doubt please contact the practice for further advice.

All rights reserved.

© Hunters Lodge Veterinary Practice 2010.

Homepage  •   Contact   •   Sitemap

©2018 Hunters Lodge Vets: Vet Guildford, Ewhurst, Cranleigh, Godalming, Worplesdon, Shere Company Registration No. 679848158

P 01483 276464  E enquiries@hunterslodgevets.co.uk

Website by: