Does My Dog Have A Flea Allergy?

What to know about flea allergy dermatitis.

Itchy dog

Your dog’s scratching way more than normal, and you’re starting to notice some hotspots on his skin.

He’s behind on his flea medication — but you don’t see any fleas on him. So that can’t be it, right?

If this scenario sounds familiar, it’s actually very possible your poor pup has flea allergy dermatitis.

The Dodo reached out to Dr. Ursula Oberkirchner, a veterinary dermatologist and owner of Advanced Veterinary Dermatology in Florida, Dr. Michelle Hall, a veterinarian at Dutch, and Dr. Brian Evans, a veterinarian and medical director at Dutch, to find out what flea allergy dermatitis is and how it can affect your dog.

What is flea allergy dermatitis?

Flea allergy dermatitis is an allergy to flea bites — and it’s actually super common in dogs.

“Flea allergy dermatitis (FAD) is one of the most common allergies in our dogs and cats,” Dr. Oberkirchner told The Dodo. “If this animal gets bitten by just one or very few fleas, it will become severely itchy and the downward spiral is then allowed to begin.”

An allergic reaction to fleas is really uncomfortable for pets, and it’s far more annoying than a normal reaction to a flea bite (which is bad enough).

“Dogs and cats who suffer from FAD typically are severely itchy and often require veterinary care to help them become and stay comfortable,” Dr. Oberkirchner said.

Oftentimes, it only takes one flea to cause a reaction, which means you may notice a reaction but not see fleas or flea dirt on your dog. Even if your other pets are totally fine and you can’t spot a single flea in your house, it’s still very possible your dog has a flea allergy.

“It is important to know that FAD is not the same as a flea infestation. If someone has a flea infestation in their home, most animals (and humans) will itch somewhat, and one can often see fleas on the animal(s) or in their environment,” Dr. Oberkirchner said.

“This is in stark contrast to FAD,” she added. “In FAD, it is often a single animal that is affected and, typically, the owners have never seen fleas on their pet(s) or in their environment.”

Signs of flea allergy dermatitis

If your pup has flea allergy dermatitis, he might show the following signs:

  • Inflamed skin
  • Bald spots
  • Increased licking, scratching and chewing on the skin
  • Infected sore on the legs, hind or tail
A dog with inflamed skin from flea allergy dermatitis | Shutterstock/fetrinka

“Most dogs with FAD itch along their back or base of their tail and, in turn, they often lose hair in those areas and develop secondary skin infections, which make matters significantly worse,” Dr. Oberkirchner said.

If you notice your dog showing these signs, you should take him to the vet immediately. They’ll be able to prescribe medications that can help him feel better fast.

Treatment of flea allergy dermatitis

Your veterinarian can help you determine the best way to treat your dog if he’s having an allergic reaction to fleas.

Some possible forms of treatment include the following:

  • Cytopoint: an anti-itch injection that lasts four to eight weeks
  • Apoquel: an immune-modulating pill that helps with both itch and inflammation
  • Cyclosporine (or Atopica): an immune-modulating pill that targets inflammation

There are some over-the-counter (OTC) medications you can use, like antihistamines, but these won’t be as effective as prescriptions — and you should ideally use them under the guidance of your veterinarian.

If you choose to give your dog an antihistamine, make sure it doesn’t contain decongestants or alcohol, which can be dangerous for him.

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Antihistamines don’t actually do much for a dog’s itchy skin, so it’s recommended that antihistamines are taken with an omega-3 fatty acid supplement.

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How to prevent flea dermatitis symptoms

Although you can’t prevent your dog from developing flea allergy dermatitis, you can prevent his symptoms by keeping fleas away from him. And the best way to do this is by keeping your dog on a reliable monthly flea and tick medication.

“The most important treatment is effective flea control,” Dr. Evans told The Dodo. “Unfortunately most of the over-the-counter flea medications are no longer effective, so it is recommended to use one of the new generation of flea treatments [to prevent fleas to start with]. These must be given consistently year-round because it only takes a small number of flea bites to create the inflammation that can last for weeks.”

And this is important for every one of your pets, not just your dog with FAD.

“To help prevent symptoms of FAD from occurring in the first place, it is crucial to use excellent and continuous flea prevention for all animals in the household,” Dr. Oberkirchner said.

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When fighting the good fight against fleas, it’s important to make sure you’re setting yourself up for success — and that means knowing common mistakes pet parents make so that you can prevent them yourself.

The most common mistakes pet parents make when it comes to fleas include:

Not being consistent with prevention

“The most common mistake and reason for treatment failure is not giving the flea preventions consistently,” Dr. Hall told The Dodo. “Most flea preventions should be administered monthly, even if you do not see fleas.

According to Dr. Hall, consistency is ideal because the adult fleas that you see only make up about 5 percent of the total population of fleas — so you need to prevent even the ones you don’t see.

Only giving prevention in the flea seasons

Many pet owners will only give flea prevention during “flea seasons” or the summer. “However, in most places, flea seasons are year-round, even in very cold and very hot climates, since fleas can complete their entire life cycle inside the home with us!” Dr. Hall said.

Not treating all household pets

Another mistake is not treating all the pets in the household. For example, if you see fleas on your dogs and you also have cats, you’ll need to treat both your dogs and your seemingly-safe cats to prevent fleas from coming back.

If you suspect your dog is allergic to fleas, don’t worry too much about it. After a visit to your vet and a product (or two!), your pup will be healthy in no time.

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