Hot Spots!
You make an appointment with your veterinarian because your dog is chewing incessantly at some wet, raw looking skin lesion.   And it seems to be noticeably bigger than it was just hours ago.  This is getting to look nasty.   You show it to your neighbor and they say your dog has a "Hot Spot".  What the heck is that, you ask?

Also known as Summer Sores or Moist Eczema, Hot Spots can seemingly appear spontaneously anywhere on a dog's body and the area involved can rapidly spread.  This moist, raw skin disorder has a variety of causes but the most consistent factor is bacteria. There are a number of kinds of bacteria that can be cultured from a "hot spot" and fortunately most respond to oral and topical antibiotics. Anything that irritates or breaks the skin can create the environment for bacterial contamination if the skin surface has just a bit of moisture on it.  That moisture can be present from a recently given bath, from swimming or being out in the rain, from rolling in wet grass or even from a slightly oozing sore that provides nutrients for bacteria.  For some reason, cats rarely acquire Hot Spots; dermatological problems in our feline friends are far less common than in the dog.