If you see Sweet itch on a horse or pony you might be forgiven for asking is sweet itch contagious? Sweet itch is not contagious and cannot be spread from one horse to another on a yard or in a field herd, like ringworm, for example. Sweet itch is the horse’s allergic reaction to the saliva of the biting midge. Every horse has an individual reaction to this which may be nothing at all, it’s just that some horses can have an allergic reaction and this gives rise to the condition.
Some horses and ponies have a propensity to develop sweet itch and some don’t, a bit like some people react to mosquito and horsefly bites with angry itchy lumps and others have only the tiniest mark on their skin. Sweet itch cannot be cured as it is the body’s response or overreaction to a foreign substance but it can be managed and owners may do a huge amount to really drive down the problem and reduce symptoms but it does require dedicated persistency.
Here are some of the steps you can take to manage a sweet itch horse or pony:-
- The midges are active at dawn and dusk so avoid turning out at either of these times
- Use a whole body fly rug or a Boett rug which is specifically designed for horses and ponies with sweet itch
- Spray the rug with insect repellent as an added layer of defence. Deet products can be very effective. Some horses can react to Deet but if you are just spraying it on the surface of the rug then this is less of an issue
- A fly rug or Boett rug can be very overheating in the main part of the day so try and turn out at night for added comfort
- Use grazing which is exposed and windy and avoid low-lying marshy paddocks or fields with ponds in – midges love stagnant air and water sources
- Whilst the horse is in the stable during the day, cover the door and windows with midge screen which are made of fine mesh. This means that you don’t need to leave the horse in his fly rug or sweet itch rug whilst he is in the box
- Stable fans can keep good airflow and discourage midges and mosquitoes from gathering
The reasons why precautions are so important is that once the biting starts – and it only takes a couple of midges – a horrible chain reaction will be set up which you will also need to treat and manage in addition to all the preventative steps outlined above. It is far better to avoid the bites from happening in the first place. Preventing sweet itch can also be sometimes at odds with managing itching and rubbing; sometimes, horses confined to the stable will have ample opportunity to rub and scratch making irritation ten times worse. This then creates a situation where the management to prevent further bites can be at odds with the management to treat existing sore and itchy skin and then life can become very complicated.
Sweet itch is not life-threatening but it is time-consuming to manage and hugely unpleasant for the horse. If you are buying a new horse then this is one question you should always ask, particularly if you are purchasing in the winter months when sweet itch is less obvious especially in horses and ponies who only have a mild response.
If your horse is already itching then what should you do?
The most important thing is to swiftly alleviate the itch otherwise the horse will carry on scratching until the skin is raw and bleeding. There are loads of different products to kill the itch but not all can be used on skin which is raw or broken so read the label carefully. The vet may need to administer antibiotics if it looks as if a secondary skin infection is present and can also usefully add in a shot of anti-histamine which will help calm the allergic response. Bute can be added to feed or administered via syringe to help with pain and inflammation.
Full stable management precautions still need to be followed whilst you are dealing with an itchy outbreak otherwise the horse will continue to get bitten.
Swiss scientists are working on a vaccine which can alter the body’s immune response so that the horse either does not react to the bite or, more likely, the reaction is milder, less painful and easier to manage. This vaccine is showing some promise and may be ready by as early as 2021.
Skin conditions in horses
Horses can suffer from many skin problems and it is important not to confuse sweet itch with something which may be contagious like ringworm. Established sweet itch horses are fairly textbook in their presentation. The skin is often permanently ridged and corrugated where it is has been rubbed so frequently and even when it is healed and not sore, the skin changes will still be clear to see.
The difficulty comes in the early stages of a skin condition when the symptoms are minor and could be indicative of another problem. A veterinary diagnosis can help confirm exactly what the horse is suffering from. There are other diseases which present in a similar way to sweet itch in the early stages and which are contagious such as rainscald which is bacterial in origin, ringworm which is fungal and definitely very contagious, lice and mange which are parasitic and also allergic reactions to environmental triggers like pollens, stable mites and other insect bites. Managing sweet itch is a long, hard slog so you don’t want to be treating something your horse doesn’t even have. Unfortunately there is no diagnostic test yet specifically for sweet itch and so diagnosis is often made by ruling out other conditions and diseases. An experienced vet is usually able to make a value judgement about what they are looking at.