Here's the full story.
My friend's horse Justin we think has a sinus infection. The vet put him on antibiotics for three weeks. He has a runny nose (chunky whitish yellow or clear dark yellow or both).
Now. As far as I know it's not anything contagious, as sinus infections generally aren't, and none of the other horses are experiencing anything.
Last March right before I got my horse, he came to the barn I was at with apparent allergies. He had a cough; when I got on to ride he'd cough every now and then, especially when we started trotting. After a few minutes though he wouldn't cough again.
Now it is March a year later, and he has a bit of a runny nose (whitish and snotty; only after riding) and he has coughed a few times when I brought him out of the field.
My trainer said it is too early for allergies, but he did this last year too so I think he may be sensitive to the changing weather.
We are keeping a close eye on it.
Could it be allergies? What do you think?
There is no smell to the discharge from my horse whereas in my friend's horse there is a definite infection smell.