Cat Flea Bite Allergy - Symptoms and Treatment

Josie F. Turner
By Josie F. Turner, Journalist specialized in Animal Welfare. September 27, 2022
Cat Flea Bite Allergy - Symptoms and Treatment

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Despite being a flightless insect, fleas sure can get around. Barely reaching 3.3 mm in diameter, they do so almost completely undetected. Their legs are supercharged to help them jump as much as 150 times their own height. As a parasite, they need hosts to survive. In the domestic environment, this is a warm blooded mammalian species. Different types of fleas will only be able to survive on certain hosts with some much more common than others. The cat flea is mainly found on felines, although many can also be found on dogs. As blood feeders, they need to bite their host to extract the blood they need as sustenance. It is this bite which causes an allergic reaction.

At AnimalWised, we look at the cat flea bite allergy. We understand how it manifests as flea allergic dermatitis and see what symptoms appear after a cat is bitten by a flea. We also look at what treatment options are available, as well as how we can prevent future cat flea bite allergies.

You may also be interested in: Do Beg Bugs Bite Cats?


  1. Cat flea bite allergy
  2. Symptoms of flea bite allergy in cats
  3. Diagnosis of cat flea bite allergy
  4. Treatment of cat flea bite allergy
  5. Preventing cat flea bite allergies

Cat flea bite allergy

Cats love to roam and investigate different areas. Although they are very careful with their hygiene, it is fairly easy for them to pick up something along the way during one of their adventures. While we may work hard to keep our home clean and hygienic, we cannot stop fleas entering our yards and outdoor spaces. If we have a cat which has access to the outdoors, there are at risk of a flea infestation.

Only certain species of flea are able to infest cats. This will depend on the area in which the cat resides. For example, the most common type of flea which infests cats in North America is the cat flea (Ctenocephalides felis). However, the cat can also be infested by other species such as the dog flea (Ctenocephalides canis). For this reason, it is possible for dog fleas to spread to cats and vice versa.

Cat fleas are a type of external parasite in felines. When a cat is infested, the adult flea will bite their skin so they can extract blood. They require the blood to complete their life cycle and reproduce. Cat flea eggs do not attach to the skin or fur of cats. It is only during the adult stage that they can infest the cat.

When a cat is bitten by the flea, a bump will appear due to the feline's immune system response. However, the degree of the immune system response will be complicated if the animal has an allergy to cat flea bites. The allergic reaction is triggered by an allergen, in this case the flea's saliva. An exaggerated reaction generally manifests itself through the release of very high levels of histamine (immune response compound).

The complex physiological and pathological mechanism of a cat flea bite allergy results in various symptoms. When the symptoms are severe, it results in something known as flea allergic dermatitis. Dermatitis refers to an inflammation of the skin which varies according to the sensitivity to the allergens in flea saliva.

Symptoms of flea bite allergy in cats

While all flea bites will cause some form of immune response, some are barely perceptible. This means cats can be infested with a small amount of fleas and be relatively asymptomatic. Cats that have an allergy to the different allergens found in flea saliva will have a reaction which can result in various symptoms. These mainly manifest in skin issues which, in turn, result in behavioral changes in the cat.

For cats which have a severe sensitivity, they will developflea allergic dermatitis. The symptoms of flea allergic dermatitis in cats will develop almost immediately after the bite and the most common are as follows:

  • Intense itching
  • Excessive licking
  • Skin inflammation
  • Redness
  • Wounds
  • Alopecia (hair loss)
  • Purulent discharge
  • Crusted skin
  • Peeling skin

As you can see, the symptoms of flea allergic dermatitis in cats are interlinked. The intense itching will cause the cat to scratch themselves to relieve the frustration. In turn, this results in the cat losing hair, as does the damage to skin follicles caused by the allergic response. Scratching from the claws can result in wounds opening in the already damaged skin. When bacteria enters the wound, the flea bite can become infected. As the infection heals, we can see scabs develop on their neck and other areas.

Infected flea bites are more common in cats with allergies. They can develop purulent discharge and even result in an abscess in the cat's skin if left untreated. Although not all cats will develop such a reaction, all that do need to be taken to the veterinarian.

Cat Flea Bite Allergy - Symptoms and Treatment - Symptoms of flea bite allergy in cats

Diagnosis of cat flea bite allergy

For minor flea infestations in cats without an allergy to flea saliva, we may not see many symptoms. Most commonly, we will see the cat scratching more than usual. Although fleas are very small, they are usually visible with the human eye if we separate their fur and look for them. They will appear as little black or brown dots, something which can be more difficult to see if the cat has dark hair.

If we suspect an allergy, we need to take the cat to a veterinarian. The diagnosis of allergic dermatitis to flea bites will be made through the clinical history and physical examination of the affected cat. We will first notice the symptoms described above and take them to the veterinarian if they are sufficiently progressed. Your vet may decide to do a blood test to confirm the diagnosis of a cat flea bite allergy as affected cats will have an abnormally large number of eosinophils, a type of white blood cell or immune defense cell.

Treatment of cat flea bite allergy

When a flea bite allergy has been confirmed, the veterinarian will establish the course of treatment. The basis of the treatment will consist of eliminating fleas from cats to reduce allergic reactions. A topical treatment with corticosteroids and/or antihistamines will also be implemented. This is aimed at reducing the symptoms associated with the allergic reaction.

Immunomodulatory therapy lacks efficacy in cats. Treatment is focused on relieving itching and preventing contact with the allergen.

Even if they do not have an allergy, you will need to get rid of fleas on cats. This is because the fleas can spread and the cat can also develop an allergic reaction at a later stage. Even cats without allergies will find the flea infestation irritating. Flea treatment for cats is a type of deworming which kills the fleas.

We can kills the fleas by bathing the cat with an anti-flea shampoo. This medicated shampoo needs to be specific for cats and it is best to use one recommended by your veterinarian. After bathing, a pipette of anti-flea deworming treatment may also be needed. The pipette contents are deposited on the nape of the cat's neck and is adsorbed over the body.

Once the fleas are killed, the cat will need regular deworming to prevent a future infestation. For this reason, it is important to establish a deworming schedule with your veterinarian. This is for all cats, but is especially important for cats with a flea bite allergy. Flea collars can also help.

Although it happens rarely, there are possible complications with certain flea treatments. Check out our article on why a cat acts weird after flea treatment to learn more.

Preventing cat flea bite allergies

If an exhaustive deworming of the cat is carried out, but do not pay attention to the fleas in the environment, another infestation is more likely. If we do not eliminate the fleas, other members of the household can be affected by them. Although cat fleas cannot fulfill their lifecycle on humans, they can cause irritation and an allergic reaction for the time they are present on our bodies.

To eliminate any flea from your home we recommend the following:

  • Carry out an exhaustive cleaning of the entire home, taking care that the products you use do not become toxic for your cat in the recommended doses.
  • If you have a vacuum cleaner, this is the best way to clean the house. It will not only remove the fleas, but also suck up all the eggs.
  • Clean all your cat's accessories, including their toys.
  • If your cat has a bed, wash it using a hot water cycle and suitable detergent.
  • Use repellents around the home or call in an exterminator if there is a serious fleas issue.

Cleaning the home is as important as deworming the cat. It should always be considered part of their flea treatment.

This article is purely informative. AnimalWised does not have the authority to prescribe any veterinary treatment or create a diagnosis. We invite you to take your pet to the veterinarian if they are suffering from any condition or pain.

If you want to read similar articles to Cat Flea Bite Allergy - Symptoms and Treatment, we recommend you visit our De-worming category.

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Cat Flea Bite Allergy - Symptoms and Treatment