Could it be a heat rash?
Most definitely.
Have you noticed if your dog is worse after being out in the yard, especially if the grass is wet from the dew or rain?
Yes. Seems to flair up in extreme heat or weather transitions when there is a lot of moisture on the ground.
We've ruled out kibble, the cottage cheese and pretty much everything ingestible, think there may be a contact allergen (ragweed is BRUTAL in this area), use metal bowls BUT use a plastic water bucket. When we first had him we used a rubber horse bucket but it was too big. Sounds like we should get a metal water bucket (yippee, an excuse to go to the BIG feed and grain store) and see if that helps. It's not particularly bothersome to him-he doesn't really scratch, his appetite is fine, and his energy level is over the top (typical springer). It's cooled off and dried out again and the bumps seem to be going away. It only happens when the whether starts to warm up then gets hot.
Susan, haven't done a scrape/culture. We had a spell of dry, warm days and cool nights and it cleared up almost completely, then came back with a vengeance on a 90+ humid day. Started to go away, it warmed up again then came back.
He's on Revolution, which we use year round, and he doesn't react during the cold seasons.
Thanks for the thoughts and suggestions. We'll keep plugging away at figuring it out.
