Hi! Sorry to hear about your horse. My mustang had the same problem. Here is what my vet told me to do. It was inexpensive, AND it worked! You may need to mildly sedate him to clean his ears. If you can, get his ears clean. Make sure all the sebum (horse ear wax) is out as best you can. A large gauze pad or a washcloth work well as they have a bit of abrasiveness to them. Once they are as clean as you can get them, put on the following mixture:
In a small plastic bowl mix approx:
2T Swat ointment
2T hydrocortisone OINTMENT
Mix well and apply to affected area. It is important to use ointment as it is thicker than a cream. The mixture provides a barrier to the area. Makes it harder for gnats, mosquitoes, and fly’s to bite. The hydrocortisone will help with the itching. If you feel like you want a little more of
one item, it’s find to customize it. Hope this helps your guy.