Is Your Dog Allergic to Fleas?

Dog allergic response to fleas is very common as flea saliva contains 15 antigens, each of which is capable of evoking an allergic response in dogs. Almost 40 percent of all dogs test positive for flea bite allergy. Dogs of both sexes and all breeds and ages can be afflicted by this allergy.


A flea is a small wingless creature that continually feeds on your pet’s blood. Flea droppings contain your pet’s blood and it is this blood that supplies the nutrients that are necessary for growth in young fleas. The saliva of fleas contains as many as 15 antigens. These antigens trigger a reaction from your pet’s immune system. Immunoglobulin is released by his immune system and this causes extreme itchiness at the site of the bite.

Flea Bite Dermatitis

Flea bite dermatitis is an allergic skin condition in dogs that are allergic to the saliva of fleas. A pet that’s allergic to fleas is unlikely to have a large number of fleas on his body. This is because his sensitivity makes him groom himself excessively and this eliminates any evidence of fleas. Just a couple of flea bites and the presence of only one flea are sufficient to cause an allergic reaction and prolonged scratching in such an animal.

Since a flea feeds continuously, your pet’s reaction to these bites makes him scratch continuously. This results in the formation of lesions, loss of hair, skin inflammation and skin thickening.

Symptoms of Flea Bite Allergy:

  • Biting at the base of the tail, back legs, rump and front legs
  • Constant itching
  • Oozing lesions caused by constant itching
  • Loss of hair at the base of the tail, back legs, rump and front legs
  • Worsening of symptoms in the summer and fall
  • Presence of flea feces on the coat that turns to a reddish brown color when placed on wet tissue paper
  • Hot spots due to severe skin damage on the hips and face
  • Inflamed skin 
  • Swelling of the skin

Diagnosis of Flea Bite Dermatitis

If you run a comb through your dog's coat and find traces of flea dirt, your pet may be suffering from fleas. To clinically confirm that your dog is suffering from flea bite dermatitis, an intradermal allergy test will be performed. This test reveals whether or not your pet develops an adverse reaction to flea antigen that's injected into his body. If your dog does develop a reaction after the test has been carried out, the vet will confirm the presence of flea bite dermatitis.

Treatment of Flea Bite Dermatitis

Baths with antiseptic soap and cool water can provide relief to your pet from the itchiness. Besides this, Hydrocortisone is one of the most commonly used medicines for flea bite dermatitis. However, you should be vigilant and monitor your pet for secondary infections as the sores caused by constant itching can become infected over a period of time. Over the counter flea medications should be used only after a discussion with the vet as they contain toxins.

You should ensure that your home, immediate environment and your pet are always clean, in order to minimize the chances of your pet suffering from flea bite allergy. Groom your pet and vacuum the house regularly to avoid flea infestations. If your pet does have fleas, medicated baths, antihistamine medications and prescription drugs can help control and eliminate the symptoms of flea allergy.