I have some very interesting factsheets in  english, that can help you as a guideline to help your horse.
This one is about Sweet itch.
 
When you read these factsheets you will understand why I find it so important to feed and pamper your horses, pets and yourself with non-chemical products, feed and high quality essential oils. 
 
I really want to share this with you as a thank you for feeding and pampering your horses with our natural products.
 
And if you think your horse could have one of these issues or other issues, please send me a message, I can help you. I am part of this knowledgeable group, specialised in horse health problems.