Flea Allergy Dermatitis in Cats

icon March 15, 2024

What is Flea Allergic Dermatitis?

Flea allergic dermatitis (FAD) is a common allergic skin disease of dogs and cats caused by an allergy to flea saliva. When a flea bites a dog or cat, it injects its saliva into the skin, which contains a number of irritating substances. In dogs and cats with FAD, the immune system overreacts to these substances and produces an allergic reaction, causing severe itching, redness, and inflammation.

FAD is one of the most common skin diseases in dogs and cats, and it is often associated with flea infestations. The condition can be difficult to diagnose because it can look like other skin diseases, and it can be complicated by secondary bacterial or yeast infections. Treatment typically involves flea control measures and medications to control itching and inflammation. Preventive measures, such as regular flea control, are important in managing FAD.

What Do Fleas on Cats Look Like?

Fleas on cats typically appear as small, dark brown insects about 1-2mm in length. They have flattened bodies, which allows them to move easily through the cat's fur, and they are usually visible to the naked eye. Fleas may also leave small black or brown specks on the cat's skin or fur, which are often referred to as "flea dirt." These specks are actually flea excrement and can be a helpful indicator of the presence of fleas. Fleas can be difficult to spot on cats with thick fur, but you may notice your cat scratching, biting, or grooming excessively, which can be a sign of flea infestation.

Flea Allergic Dermatitis in cats






What Do Cat Fleas Look Like to the Human Eye?

Cat fleas are typically small, dark-colored insects that are about 1 to 2 millimeters in length. They have flattened bodies that are well adapted for moving through the fur of their hosts.

To the human eye, cat fleas may appear as tiny specks that are difficult to see without close inspection. However, when viewed up close, they can be identified by their dark brown color and the presence of long, powerful legs that are adapted for jumping.

Symptoms of Fleas Allergy Dermatitis in Cats

Flea allergy dermatitis (FAD) is a common allergic skin disease that affects cats and is caused by an allergic reaction to flea saliva. Here are some common symptoms of FAD in cats:

Intense itching: The most common symptom of FAD in cats is severe itching. Cats affected by FAD may scratch and bite their skin excessively, especially on their back, tail base, and hind legs.

  • Hair loss: Due to excessive scratching, cats with FAD may experience hair loss, especially on their lower back, belly, and inner thighs.
  • Skin inflammation: Cats with FAD may develop inflamed and irritated skin, which may appear red, swollen, and tender.
  • Skin lesions: FAD can cause small, raised bumps, scabs, and crusty skin lesions on the affected areas of the cat's body.
  • Licking and chewing: Cats with FAD may lick and chew their skin, causing bald spots and open wounds.

Secondary infections: Due to the damage caused by excessive scratching and licking, cats with FAD may develop secondary bacterial or fungal infections on their skin.

Causes of Flea Allergy Dermatitis in Cats

  • Cats with FAD are hypersensitive to flea saliva, and even a single flea bite can trigger an allergic reaction. The bites can occur anywhere on the cat's body but are most common on the lower back, tail base, and thighs.
  • Flea infestations are a major cause of FAD in cats. When fleas reproduce and feed on cats, the allergic reaction can become severe, leading to intense itching, redness, and inflammation.
  • Cats that do not groom themselves properly may be more susceptible to flea infestations, as their coats may become matted and difficult to clean. This can create a perfect environment for fleas to thrive, leading to FAD.

Treating Flea Allergy Dermatitis

Flea allergy dermatitis (FAD) is a common skin condition in dogs and cats caused by an allergic reaction to flea bites. The best way to treat FAD is to prevent flea infestations and reduce exposure to fleas. 

How to Soothe Flea Allergy Dermatitis in Cats

  • Use Fipronil: Use the Fipronil medication recommended by your veterinarian that kills and prevents fleas from infesting your pet's fur.
  • Treat the environment: Fleas can survive in your pet's environment such as bedding, carpets, and furniture. Use flea sprays or foggers to treat your pet's living area, and wash all bedding and furniture covers in hot water to kill fleas and their eggs.
  • Manage to itch: To help relieve the itching associated with FAD, your veterinarian may prescribe spray for Antibacterial and anti-inflammatory effects. You can also try using a soothing oatmeal shampoo or apply a cold compress to the affected area.
  • Monitor for fleas: Regularly check your pet for fleas and flea dirt (tiny black specks that look like pepper flakes). If you notice fleas, use a flea comb to remove them and dispose of them immediately.

recommended drug

Puainta® Multifunctional Skin SprayPuainta® Abamectin B1 Topical Deworming Drops to Kill Fleas & Ticks in Dogs/Cats

Puainta® Topical Fipronil Drops for Fleas & Ticks in Dogs/Cats+Puainta® Multifunctional Skin Spray

Prevention of Flea Allergy Dermatitis in Cats

  • Regular deworming: Use a flea preventive medication recommended by your veterinarian monthly to prevent flea infestation. It is recommended to do deworming once a month for cats. If the cat often moves indoors, it can also be relaxed once every 3 months.
  • Note: If the cat has just been vaccinated, it cannot be dewormed within seven days. If the cat has just arrived at a new home, it is recommended to deworm it after 3 to 5 days. Recommended flea control products include:
    • External medicine: Abamectin b1, fipronil
    • Oral: Capstar (can be taken daily as needed; treats live flea infestation but does not prevent fleas)
  • Keep your home clean: Vacuum and wash your cat's bedding regularly to remove fleas and their eggs from the environment.
  • Groom your cat regularly with a flea comb: Regular brushing and grooming will help remove fleas from your cat's coat before the cat has a chance to bite and cause an allergic reaction.


Can Cats Get Fleas in The Winter?

Yes, cats can still get fleas in the winter. While fleas are more commonly associated with warmer weather, they can survive indoors in the winter months and continue to reproduce on a pet. Additionally, some areas may have mild winters that allow fleas to survive outside year-round. It is important to regularly monitor your cat for fleas and take preventative measures, such as using flea medication, to keep them flea-free.

Can Miliary Dermatitis Kill a Cat?

Miliary dermatitis, also known as "feline eczema" or "scabby cat disease," is a common skin condition that affects cats. While it can be uncomfortable and unsightly for the cat, it is not typically life-threatening.

Miliary dermatitis is characterized by the appearance of small scabs or bumps on the cat's skin, which may be itchy and inflamed. The condition is often caused by an allergic reaction to flea bites or other environmental allergens.

In rare cases, if the cat's skin becomes severely infected or the underlying cause of the condition is not properly addressed, it is possible for complications to arise that could potentially be life-threatening. For example, a severe bacterial infection could lead to sepsis, which is a serious and potentially fatal condition.

How Long Do Flea Bites Take to Show Up?

Flea bites typically appear on the skin within a few hours after being bitten. However, some cats may not notice any symptoms for several days or even weeks, depending on their individual sensitivity to flea bites.

The initial sign of a flea bite is usually a small, red, itchy bump that may be surrounded by a red halo. The bites are often grouped together in clusters or lines, and they may appear on any part of the body but are commonly found on the legs.

When Do Flea Bites Go Away?

The duration of flea bites can vary depending on the individual's reaction to the bite and the severity of the infestation. In general, flea bites usually go away within one to two weeks, although they may last longer in some cases.

Why Do Cats Bite Each Other's Necks?

Biting each other's necks is a common behavior among cats, especially during play or mating.
  This behavior is usually harmless and is a way for cats to feign aggression, practice hunting skills, and establish dominance over each other.
Male cats often bite female cats on the neck during mating, which helps stimulate ovulation and promotes fertilization. The bite also helps hold the female in place during copulation.
Not an act of getting fleas

How Long Do Cats Itch After Flea Treatment?

The duration of itching in cats after flea treatment can vary depending on the type of flea treatment used, the severity of the flea infestation, and the individual cat's sensitivity to the treatment.

In general, cats may experience itching for a few days to a week after flea treatment. This is because the treatment can cause irritation and inflammation on the skin, which can result in itching. However, if the itching persists for more than a week or if the cat shows signs of discomfort, such as excessive scratching or biting at the affected area, it is important to consult a veterinarian to rule out any potential allergic reactions or other health issues.

It is also important to note that regular flea prevention and control measures are crucial to prevent flea infestations in cats and reduce the need for frequent flea treatments, which can cause discomfort and irritation. Your veterinarian can recommend the best flea prevention and control methods for your cat's individual needs

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