What is sweet itch?
Sweet itch is the most common allergic condition seen in horses thought to affect around five percent of the equine population in the UK. Sweet itch is an allergic reaction to the saliva in the bite of biting insects - primarily culicoides and horse-flies. When bitten, an immune response is triggered where the immune system will produce antibodies to attack the pathogen found in the insect saliva. Histamine is also released into the bloodstream which promotes an inflammatory response causing the symptoms associated with an allergic reaction.
Sweet itch can affect all types of horses however it is more commonly seen in native and heavier built breeds. The condition is also more prevalent in ponies than it is in horses.
Symptoms of sweet itch
The symptoms of sweet itch are not pleasant and include
- Intense itching
- Lumps and swellings on the skin
- Bald patches and hair loss as a result of scratching
- Dull coat accompanied with dry, flakey and irritated skin
- Head shaking, hoof stamping and tail swishing
- Behavioral changes - many horses will become agitated or lethargic as a result of the condition
- Self mutilation may be seen in severe cases
Tips to manage sweet itch
Biting insects that cause the condition are most active during the months of March - November, preventative measures should be taken throughout these months to help manage the condition. We have compiled a list of our top tips to manage sweet itch.
- Make use of fly protection through use of fly sprays, fly sheets and fly masks. Fly sheets and masks are lightweight and breathable meaning they can safely be used in warm weather without the risk of overheating your horse. Regularly check for signs of wear and repair damage as soon as possible to ensure sheets and masks continue to provide optimum protection.
- Make use of topical creams, ointments and washes to treat and soothe dry, itchy skin. If turning out in hot weather avoid using oil based products as this can cause hypersensitivity.
- On warm days hose horses down after exercise to remove any sweat which may attract biting insects.
- Where possible avoid grazing from dusk-dawn as this is when biting insects will be most active.
- Avoid turning horses out in water logged or marshy areas as midges thrive in these conditions.
- Ensure that water drinkers and buckets are cleaned regularly to prevent algae build up which can attract midges.
- Poo pick or harrow fields regularly to remove build up of droppings which can attract flies.
- Limit starch intake in the diet as research suggests excessive dietary starch can exacerbate the condition.
- Consider feeding dietary supplements targeted for sweet itch. A high quality oil such as linseed oil can be included in the diet to help promote skin health and revive a dull coat. Linseed oil is one of the few oils which has an appropriate Omega 3 to Omega 6 fatty acid ratio to promote an anti-inflammatory response within the body. Garlic is also a good addition for horses with sweet itch due to its naturally occurring anti-inflammatory and insect repelling properties.
- In severe cases it is recommended that owners consult a vet who may recommend a steroid injection. Corticosteroids work by suppressing the immune system's response to the allergen, reducing inflammation, decreasing the production of histamine and minimising the symptoms associated with the condition however they will not cure or prevent the condition. In order to be effective, sweet itch vaccines should be given prior to the beginning of sweet itch season, February is normally a good time of year to consider this.
It can be frustrating and upsetting seeing your four-legged friend in discomfort. Understanding the causes, symptoms and management practices for sweet itch can help alleviate discomfort and improve your horse’s overall wellbeing this summer.