Sweet Itch in Horses
Sweet itch is caused by an allergic reaction to insect bites and is usually associated with the Culicoides midge
What is Sweet Itch?
Summer Seasonal Recurrent Dermatitis, more commonly referred to as sweet itch, is known to be one of the more difficult diseases to manage and those who have horses with the condition will have been managing it from early Spring time.
There are now a wide range of products available on the market and it can be hard to know what is effective and what is a fad, but firstly we need to understand the cause and what signs to look for.
Sweet itch affects horses and ponies of all shapes, breeds and sizes, (although is less commonly seen in Thoroughbreds), it is thought that up to 5% of horses in the UK show signs of some degree of the condition. Once developed, it is usually a life long condition, however with effective management strategies put in place all year round many horses can go on to lead normal lives and be unaffected by this awful condition.
Why do horses get sweet itch?
Sweet itch is caused by an allergic reaction to insect bites, it is usually associated with the Culicoides midge and, to a lesser extent, the larger, hump-backed Simulium Equinum, a member of the black fly family.
While many horses get bitten by midges and seem to show no effect, for sufferers, these bites cause a delayed hypersensitivity which results in an immune response to insect saliva. This over reaction causes the horse to attack its own skin cells, which results in the symptoms we know as sweet itch.
What are the symptoms of sweet itch?
Classic symptoms include severe itching (pruritis), which leads to hair loss and in severe cases can lead to weeping sores. If left untreated, these sores can sometimes get secondary infections, which will require attention from your vet and usually a course of antibiotics.
It is usually seen around the mane and top of the dock, but in severe cases sweet itch may also be seen over the neck, withers, ears, forehead, hips and mid-line of the belly.
The itching is usually seasonal, triggered by insects in spring time, but can continue into the winter months. Horses usually develop sweet itch from an early age, although stress can sometimes trigger it in older horses so don’t presume your horse will always be ‘immune’.
Prevention and management
Excellent management practices are vital with this this condition. There are several products containing high levels of Vit B (or nicotinamide, although for the best results this needs to be started before any symptoms appear.
When do I need to use the sweet itch vaccine?
The sweet itch vaccine can reduce the severity of the condition – importantly these 2 injections need to be given around February time, BEFORE any midges start biting.
Management for reducing sweet itch symptoms
Management is the most important aspect of dealing with the condition. It is important to take preventative precautions to stop the horse from getting bitten before the vicious cycle starts.
The most effective management strategies are specialist sweet itch rugs that should be put on before the temperature reaches double figures and should be worn for 24 hours a day. Fly masks are also important to prevent bites to the forelock, face and ears.
Is the field or stable better?
Traditionally it was thought that by stabling your horse during dawn and dusk it would help prevent bites. While this can be true in lovely cold stone stables, it is not always the case in warmer wooden boxes – never assume that just because the horse is inside he will not get bitten. You should still keep him rugged up even inside.
Streams, trees, marshy land, muck heaps and manure all attract flies and midges so if possible house your horse away from these. A hillside or coastal location may be preferable due to the increased breeze, although not always practical or possible.
Remove muck from your field regularly to help to reduce flies, and also to help with your worm management programme.
Treatments for sweet itch
Start applying your chosen cream or spray early on in the season, and if possible use a product that contains DEET as it is proven repellent, although be careful what products you use if you are competing). It is also worth remembering that repellent applied to clean horses will work more effectively than a dirty horse. Neem oil is another popular choice for many horse owners wanting to deter midges and flies.
Benzyl benzoate is another product commonly used as a preventative and is available from your vets or local chemist. This should be thoroughly worked into the skin, although should not be used if the skin is broken.
Washing your horse regularly has been proven to help reduce itchiness, although be careful which shampoo you use as horses that suffer from sweet itch have sensitive skin. Use a non-allergic shampoo and make sure that all the soap is washed out thoroughly.
It is important to continue with your management strategies so as not to exacerbate the situation. The clinical signs (itching) can be treated by a number of products including topical creams but in more severe cases steroid cream may be needed.
If your horse shows severe signs of sweet itch or weeping sores you should contact your vet. As with a lot of conditions prevention is better than cure, so if you know your horse suffers from sweet itch start preventions early to stop symptoms developing.
If you would like any additional information please call us on 01577 841010.
