Don't be fooled into thinking that hives amoxicillin reaction must be an allergen that has been recently introduced into your dog's environment, your dog may have tolerated the irritant in the past and only just developed an allergy to it.
The process of finding the exact allergen is one of trial and error (and lots of patience). Rather than switching out the possible irritants one by one, try and remove as many as you can (pet beds, perfumes, colognes etc) and give your dog time to recover. If you see an improvement then you know it's one (or more) of the items removed. Then you can reintroduce the offending items one by one leaving time for the reaction to occur again. This way you'll be able to isolate the specific allergen and remove hives amoxicillin reaction permanently. (This method also allows for the fastest relief)
Food allergies are another common cause of itching and again it's quite common for a food that had been well tolerated for years to become the source of the problem. It's a good idea to rotate out all of your dogs food but be especially suspicious of food containing wheat, grains and peanuts. If your dog is particularly prone to allergies you might want to try an herbal detoxifier to help reduce the overall allergic load on their system. Find out more here
Parasites are reasonably easy to diagnose, larger ones like fleas and ticks can be seen with the naked eye and can be killed by using an over the counter flea treatment. If you prefer to be a little more proactive and prevent an infection before hives amoxicillin reaction occurs an all natural spray. If you find no sign of parasites but still suspect they may be the cause you can also take your dog to a vets for a skin scraping that will indicate any microscopic cause of the problem. Your vet will probably prescribe Ivermectin, an anti-parasitic medication.
Another common cause of canine itching is shampoo residue. Never use human shampoo on your dog, hives amoxicillin reaction has the wrong pH for a dogs skin and tends to lather much more than needed. (Humans usually have far less hair than dogs) A low lathering shampoo will not only prevent residue build up but the colloidal oatmeal formula is very effective at combating itching in the first place.
With a little luck and diligent detective work you can make those nasty bumps disappear and bring peace and quiet back to your itchy household.