Flea allergy dermatitis is one of the most common skin allergies in dogs. Dogs that have a flea allergy are hypersensitive to the flea’s saliva, which is passed into the dog’s skin when it bites. It only takes a couple of flea bites to cause pain and suffering in an allergic dog.
Many dogs with other inhalant allergies will become allergic to fleas as well. They usually become sensitive between two to four years of age. When an allergic dog is bit by a flea, they will scratch and bite at their skin – often causing hair loss, skin lesions, and red inflamed skin. Dogs with flea allergies often have thinning hair above the base of their tails.
If you are concerned that your dog may be suffering from a flea allergy, you should check to see if there are signs of fleas on their skin. If you don’t see the fleas themselves, you may see some proof of their existence. Fleas will leave behind flea dirt (or feces) which are dark brown or black flecks left behind on your dog’s skin. When introduced to water, this flea dirt will turn a reddish color. However, this flea dirt may not always be visible on your dog even if fleas are present.
The best thing you can do to prevent flea allergies, is to make your dog inhospitable for fleas. We discuss some suggested flea prevention steps in our Allergy Treatments section.