Greetings, and thanks for the question!
I’m sorry to hear about Elton’s condition. Fly/insect bite reactions can become sever if a horse has a high sensitivity to them. Some horses have more of an allergic response than others, and unfortunately, it sounds as if Elton may be one of the unlucky ones, with a high sensitivity. I’d like to ask you a few questions concerning Elton, so that I may give you a thorough answer.
1): Where are you located, and what has the weather been like?
2): Is the pasture where Elton is living irrigated?
3): What type of insect sprays have you been using, and do they seem to be effective?
4): Do the sores from the insect bite seem to be healing, or are they increasing in number, getting worse, etc.?
5): Is there any possible way that you could get some photos of the sores and send them to me (that could be extremely helpful)?
Many thanks, ***** *****’m looking forward to hearing from you.
-Dan C., DVM.