Hot spots are areas on a dog that are infected by normal skin bacteria, run amuck. The normal bacteria have basically overwhelmed the dog’s normal immune resistance and have begun to cause painful itching. Hot Spots are the lay persons way of referring to what veterinarians would diagnose as Pyotraumatic Dermatitis. Hot spot is much easier to remember and it looks like what the words say–circular patches that may smell badly, lose hair, swell-up, ooze pus, and cause incredibly ferocious scratching, licking and biting by a seemingly tortured dog.