There are topical solutions you can get at your vet to help with the skin. Resicort is a nice one and my previous dog, Daisy, did well on it. Also think about giving your dog fish oil pills. My new puppy has been itching a lot (not fleas or ticks) and the fish oil pill idea from the vet has worked well. Also, brush your dog every day. The brushing will stimulate the oil glands on your dogs skin. Lastly, try a dog food that is formulated for sensitive skin- and make sure you use hypoallergenic doggie shampoo as well.
Be careful with some of the foods that say for sensitive skin on them. A lot of them are not much better than the rest of the junk. Even the commonly prescribed Hills Prescription Diets won’t fix the problem, and will set you back quite a few dollars. As I mentioned above, California Natural is a good one for testing the food allergy theory. Pugs often have sensitive skin and allergy issues, and food allergies are really common. Also, make sure he is getting enough water, and pugs can be susceptible to heat more than other breeds.
You can use benadryl, but ask your vet for the recommended dosage.
Also, of course check for ticks and fleas. They can also leave bumps.
Fish oil is a good idea too.
You beat me to the punch. First thing I would check is the thyroid. In fact, it would be the thing I would hope for, since it’s much easier to control than allergies.
As for the allergies, there are specialists out there and if you have the $$ that’s where I would go next. I have had dogs with allergies, and it’s not a pleasant thing. You can help with the special diet, shampoos, benedryl, etc, but nothing cures it. I also don’t like to do the pred long term, altho some dogs get relief for a long period of time one an injection, so it might be worth trying.
Last but not least, when I fed raw food to my dogs none had itchy skin or ear infections. It can be a bit of a pain in the neck, but they were healthier and had the most beautiful, clean teeth (even my old girl).
susie