Hot spots (flea allergy dermatitis) is a skin disease (dermatitis) caused by your pet's allergic reaction to fleas. Derm means skin, and "itis" means inflammation, so your pet will have itchy, inflamed skin. Inflamed skin is hot, red, and itchy. Often the skin becomes smelly because yeast and bacteria grow well on unhealthy, inflamed skin. When your pet scratches the bacteria are rubbed deep into the skin and hot spots develop. Hot spots are just infected sores.Pets with flea allergy dermatitis are so sensitive they can develop hot spots if bitten just twice a month by fleas. Your pet is having an allergic reaction to flea saliva, feces and exoskeleton.
About one in five visits to a veterinary office is for skin problems, and hot spots are often the culprit. In fact, fleas cause more dermatitis than any other insect. While food allergies are the most common cause of year-round itching, fleas are the most common cause of seasonal itching.
Any pet can develop allergies to fleas, and pets with atopy (a genetic inclination to develop skin allergies) have the biggest problem. Between 3-15% of dogs have atopy; and the breeds with the biggest problems vary country to country, so you'll find a different list of British dogs with atopy than of American dogs with atopy.
American dogs with atopy include:
Many terriers also have atopy:
Cats can develop flea allergy dermatitis (hot spots), but there is no clear breed predisposition.