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Flea Allergy Dermatitis (FAD) in Dogs

Flea Allergy Dermatitis

Flea Allergy Dermatitis is the most common skin disease and cause of itching in dogs. For adult fleas to reproduce they must bite a dog to obtain a blood meal. Most of the flea life cycle is not spent on a dog but in their environment, with adult fleas only remaining on the dog long enough to feed and obtain a blood meal. This explains why owners often do not see live fleas on their dog unless there is an overwhelming flea infestation in the environment where they live. When fleas bite a dog to feed, it allows a small amount of saliva to get into the skin. Flea saliva contains proteins or antigens which lead to a severely itchy response in dogs sensitive or allergic to fleas. Continue reading to learn more about Flea Allergy Dermatitis and how to help your dog.

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Symptoms of Flea Allergy Dermatitis in Dogs

  • Dogs with FAD experience raw, irritated, or bleeding areas of skin or a rash found typically from the middle of the back to the tail base and down the rear legs.
  • Loss or missing hair particularly where they have been bitten by fleas
  • Hair may be stained brown from constant licking and is often broken off.
  • Skin with small red or pink raised bumps that can look like pimples.
  • Dogs with FAD experience intense, constant itching and will often bite, claw or groom themselves constantly which can result in self-trauma and secondary skin infection, including moist dermatitis (hot spots).
  • Over time dogs with FAD can lose hair all over and develop skin problems such as severe seborrhea, hyperkeratosis, and hyperpigmentation (discoloration of the skin).

How is Flea Allergy Dermatitis diagnosed in dogs?

“My veterinarian says my dog has Flea Allergy Dermatitis causing his skin problems. How is that possible when I have never even seen a flea on my dog?”

Since dogs with FAD often groom constantly, removing fleas from their fur, you may not see any fleas. With FAD, the allergic reaction from the flea bites can continue for several weeks, causing the symptoms described above. Dogs with FAD only need to get one flea bite to develop itching lasting several days. This also means they do not need to be flea-infested to get itchy.

If you suspect FAD in your dog, schedule an appointment with your vet. Diagnosing FAD will include a thorough history, signs or symptoms, checking for fleas or flea dirt (excrement), ruling out other causes, and in some cases, intradermal allergy skin tests or specialized blood tests.

Other causes of skin diseases in dogs that must be ruled out include atopic dermatitis, food allergy dermatitis, sarcoptic or demodectic mange, other skin parasites, and bacterial folliculitis.

The signs of FAD in dogs are often typical as described above with rapid response to treatment, making allergy testing needed only in some cases.

Treatment Options for Dogs with Flea Allergy Dermatitis

The best treatment for dogs with FAD is flea prevention. Flea saliva from a flea bite leads to an allergic reaction, making it vital to control fleas on your dog as well as the environment. For dogs with FAD, this means year-round oral or topical flea preventives as well as treating the environment, particularly during warmer weather.

Dogs with secondary skin infections or other skin problems due to FAD may need medications including antibiotics, steroids to give short-term relief, antihistamines, supplements, and medicated shampoos.

Soothe your dogs’ inflamed skin by bathing them in a bath using cool water, unless your dog dislikes being bathed. While this only provides short-term relief, it helps their skin feel better and also removes some fleas.

In severe cases of FAD with flea infestation, supportive care may be needed for dogs with blood loss or anemia.

Prevention and Control of Flea Allergy Dermatitis

There are many choices for year-round flea preventive medications including topical (spot-on), oral medications, and medicated collars. Always talk to your vet to determine which flea preventive is safest and best for your dog, taking into account their medical history and lifestyle.

Fleas only jump on your dog to feed, spending most of their lifecycle living in carpets, bedding, and other nooks and crannies in your home. Remember to wash your pet’s bedding and yours too (if your pet sleeps with you), as well as throw rugs with detergent and warm/hot water.

Vacuum your home, including the carpets, chairs, sofa cushions, baseboards, and underneath furniture to remove fleas, flea eggs, and flea larvae. Remember to empty the vacuum canister or bag outside or the fleas can crawl/hop back out into your home.

Consider treating your outdoor area periodically as well to help control the fleas. Wildlife and other dogs and cats that pass through your yard can carry fleas which can then hop onto your dog.

Read more:

Why is my dog itchy?

Common Myths About Allergies in Dogs

Allergy Tests for Dogs

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