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My Dog is Having a Reaction to Flea Bites

Dog is Having a Reaction to Flea Bites

It's normal for dogs to be itchy when they have fleas, but when the itching is quite severe, there are chances that your dog is having an allergic reaction to flea bites. In a dog with an allergy to flea bites, just the mere presence of only one or two fleas is often enough to cause them to feel miserable and go into an itching frenzy. These dogs will itch and scratch and sometimes may act panicky too when they cannot easily reach the itchy areas. Fortunately, this condition can be treated by eradicating the flea population, but it's important to know how to do this correctly.

dog bunny hopping

Allergic to Flea Saliva

When dogs have a reaction to flea bites, they are basically showing a reaction to flea saliva. Dogs allergic to flea saliva, develop what's medically known as flea allergy dermatitis.

These dogs have become sensitive to allergens that are found in flea saliva and develop dermatitis, an annoying inflammation of the skin. The itchiness can be seasonal or year-long depending on where the dog lives and climate.

For instance, in Texas and other places in the south where winters are mild, fleas may thrive year-round, causing nonseasonal, year-round itching in dogs.

However, just because you live in a cold climate, doesn't necessarily mean you won't see fleas in the winter. Fleas can make themselves comfy in the house during the winter months and they show signs of thriving too.

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"The most common time of the year where I see flea infestations in dogs is December, January and February, says Dr K. Not surprisingly, these months coincide with when dog owners put their guard down and stop applying flea products to their dogs.

Symptoms of Flea Allergy

dog bunny hops when running

Typically, dogs affected by flea allergy dermatitis develop skin lesions mostly located by the tail area, rump, thighs. abdomen and back. The skin lesions may develop as crusts, hot spots and hairless areas from the constant scratching. At times, opportunistic bacteria may set in the scratched skin and cause annoying secondary bacterial infections. Yeast infections at times may also pop up.

Often dog owners rule out fleas when their dogs are acting very itchy just because they do not see fleas on their dogs. Fleas though can be quite difficult to spot, they are very quick and can easily hide in all that fur. You can repeatedly brush your dog with a flea comb, but may never find a single flea if the fleas are scurrying quickly along the surface of the skin.

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Perhaps a better way to identify the presence of fleas is looking for the presence of "flea dirt." Flea dirt refers to small blackish or brownish flacks that are found near the base of a dog's fur. These specks are simply the flea's droppings.

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If you collect some of these specks and want to make sure they are truly flea droppings and not dirt or debris, place them on a paper towel and then drip some water on them. If the paper around them turns red, then you are are dealing with flea droppings, explains veterinarian Dr. P.  And in case you are wondering, the red color is due to the fact that flea droppings are mostly composed of digested blood!

At the Vet's Office

Causes of dog hallucinations

Your vet will look at the lesions looking for fleas or flea dirt and will determine whether the itchiness is caused by something else. There are several other skin problems that may resemble skin allergies to flea bites such as food allergies, atopy, mange, skin contact dermatitis and skin infections. Diagnostic tests may include several skin tests. In particular a positive flea antigen test can help determine an allergy to flea bites.

Treatment for flea allergy dermatitis obviously consists of proper flea control. Many dog owners believe that just because they applied flea products, fleas will magically be wiped off their dogs. In reality, it takes some time for these products to kick in and start working, and this delay is often long enough for fleas to bite, explains Dr. Carlo Vitale, a veterinarian specializing in dermatology at San Francisco Veterinary Specialist.

While flea products on the dog tend to kill fleas on their coats, it's also important killing the more juvenile forms found in the environment using insect growth regulators (IGR's). Ask your vet about these. If your dog has flea allergy dermatitis your vet may prescribe products such as Program, Sentinel, Capstar, Comfortis, Vectra 3D, Advantage, Avantix and Frontline plus. Some of these products may be toxic to cats, so if you have cats in the home, let the vet know. These products often available by prescription.

Dog owners should consider that over-the-counter flea control products are not as strong as the prescription ones and some can even be toxic. Severe cases of flea allergy dermatitis may benefit from by a glucocorticoid like prednisone which should work wonders in giving relief to dogs allergic to the saliva of fleas, points out veterinarian Dr. Michael Salkin.


  • DVM360, Facts about flea allergy dermatitis

Photo Credits: 

  • Wikipedia, Dog with flea allergy dermatitis and secondary folliculitis, self - Own work CC BY-SA 3.0

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