Flea Allergy Dermatitis Cats – Symptoms & Treatment

Table of Contents


What Is Flea Allergy Dermatitis In Cats? 

Flea allergy dermatitis (FAD) is, in fact, flea bite hypersensitivity or a specific type of dermatitis (skin infection) triggered by an allergic reaction to cat flea saliva. 

When fleas bite or, better said, attach their mouthparts (proboscis) to a host, they inject a small amount of saliva. Flea saliva contains proteins that, in a sensitive cat, may trigger an allergic reaction. 

What Are Allergies? 

Allergies are specific reactions that occur when the immune system misidentifies certain substances as dangerous (foreign) and overreacts to their presence. The mislabeled substances are called allergens, antigens, or triggers. 

How Many Types Are There?

In cats, there are four types of allergies – contact allergies, inhalant allergies, food allergies, and flea allergies. In parts of the world where the flea populations are dense and present year-round, flea allergies are the most common type.  

What Are The Signs & Symptoms Of Flea Allergy Dermatitis? 

Excess scratching and skin lesions (bumpy rash and hair loss) are the two telltale signs of flea allergy dermatitis in cats. 

Excess Scratching. Interestingly, the amount of scratching is not proportional to the number of fleas – in sensitive cats, even one flea bite is enough to trigger an allergic reaction. 

Skin Lesions. As for the skin lesions, they are usually distributed on the cat’s head, neck, back, and base of the tail – a specific pattern called “racing stripe.” 

A cat with flea allergy dermatitis will also show signs and symptoms associated with the flea presence, such as: 

  • Flea dirt
  • Overgrooming 
  • Restlessness 
  • Irritability 

Overall, the clinical manifestation of FAD in cats is dramatic and easy to notice. Even first-time cat parents will quickly notice something wrong is going on. 

How Is Flea Allergy Dermatitis In Cats Diagnosed? 

An experienced vet will suspect FAD as the diagnosis based on the clinical signs. Finding fleas or flea dirt on the cat further supports the suspicion. If fleas or flea dirt cannot be found (which is possible in cats considering their grooming habits), 

In such cases, the vet can confirm the diagnosis through specific procedures like blood tests (IgE tests) and intradermal allergy tests. 

What Is The Treatment for Flea Allergy Dermatitis In Cats? 

The treatment for flea allergy dermatitis in cats includes: 

Getting Rid Of The Flea Infestation  

To eliminate the fleas, the vet will recommend an anti-flea product which can be in the form of spot-on liquids or oral medications (tablets or chewable treats). 

Based on the type of product, you may need to repeat the treatment. Also, if you have a kitten, you will probably have to manually remove the fleas, as chemical treatments can be dangerous, 

Managing The Symptoms

Based on the exact symptoms and their severity, this includes: 

  • Soothing Baths: There are many shampoos formulated with ingredients that provide temporary relief (from the itchiness). 
  • Antibiotics: Antibiotics are prescribed in severe cases when the itching results in a secondary skin infection. 
  • Steroids: Steroids reduce skin irritation and relieve itchiness. Some cats respond better to long-lasting injectable steroids and others to oral pills.

Are There Home Treatments For Flea Allergy Dermatitis? 

Yes, there are home treatments for FAD, but they focus on flare-up management rather than problem eradication. 

For example, a popular home remedy is bathing in lukewarm or cool water with an oatmeal shampoo. After the bath, a 1% hydrocortisone spray can be applied to the skin lesions. 

However, there are two caveats. First, the relief provided by home remedies is only temporary. Second, hydrocortisone spray must not be applied on wounds  (skin ulcers & deep scratches) as it will worsen the situation.  

Bottom line, if dealing with a FAD, take your cat to the vet and stick to the vet’s treatment protocol and instructions. 

How Can I Prevent Flea Allergy Dermatitis In My Cat? 

Luckily, preventing FAD in cats is very simple – all you need to do is keep your cat up-to-date on flea preventives. Plus, there are many anti-flea products on the pet market – some available over-the-counter and others through vet prescription. Here are some options: 

  • Spot-On Liquids: Spot-ons are readily available (often over-the-counter) and easy to use. Their residual effects are not very lasting, but the price is budget-friendly. However, they can make the cat’s coat greasy around the application site. 
  • Oral Medications: Oral medications are fast-acting and with long residual effects. The only issue is that they can be hard to use. Cats are notoriously fussy eaters, and administering oral meds can be challenging. 
  • Flea Collars: Finally, you can use flea collars. They are very efficient and have long-lasting effects (up to seven or even eight months). However, collars are not recommended for free-roaming outdoor cats as they can get stuck on a branch.  


Is Flea Allergy Dermatitis In Cats Common? 

Depending on where you and your cat live, FAD can be the most common type of allergic dermatitis (if fleas are present) or non-existent (if fleas are not present). 

Is Flea Allergy Dermatitis Contagious? 

No, flea allergy dermatitis is not contagious. However, the fleas causing the issue are a danger to all pets in the house. 

Is Flea Allergy Dermatitis In Cats Dangerous To Humans? 

FAD is not dangerous to humans, but its trigger (fleas) is. Namely, flea allergy dermatitis is not contagious to humans. However, cat fleas (despite the name) are not picky eaters and can bite humans too. 

How Long Does Flea Allergy Dermatitis In Cats Last? 

With proper treatment, the symptoms of FAD can resolve within a few days, but if left unmanaged for a longer period, they may persist for months. 

Do Allergy Shots Work For Flea Allergy Dermatitis In Cats? 

Allergy shots (desensitization) do not work for all cats with flea allergy dermatitis. Since the efficacy is unpredictable and variable, they are not recommended as a routine management option.  

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