Dental Disease
Did you know that the majority of pets—up to 85 percent—over the age of three have some form of dental disease? You would, too, if you went three years without brushing your teeth
Ear Infection
Allergies in pets are also a common cause of ear infections. Some dogs may simply be prone to developing ear infections because of their anatomy, such as hounds with long, droopy ears that trap moisture
Kidney Disease
Pets with kidney disease suffer from the inability to eliminate waste products from the bloodstream, which build up and can create an ammonia-like odor to your dog’s breath.2 Some people also say that pets in kidney failure have a metallic odor to their breath
Diabetes
Pets in late-stage diabetes may also have a unique odor to their breath. If your dog is either not producing enough insulin or not using insulin properly, her body will be unable to use the food she eats for nutrients.
Skin Infection
Dogs with wrinkly skin, such as English bulldogs, Shar Pei's, or pugs, are prone to developing skin fold dermatitis.3 This stinky skin disorder occurs because of close skin contact, creating a warm, moist environment perfect for an overgrowth of surface microbes, such as bacteria and yeast
Anal Sac Issues
Anal sacs are two small glands located on either side of your dog’s rectum that emit a thin, foul-smelling fluid when your pet defecates. Occasionally, pets may suffer from anal sac infections or impactions, causing them to lick their hind end excessively or scoot along the floor to relieve the pressure from full anal sacs
Flatulence
Some dogs have powerful enough gas to clear a room, usually after they’ve eaten something particularly nasty, such as moldy trash or a rotting carcass