Flea Collar Itch. Why is Kitty Still Scratching?


Flea infestations are very common in cats, and flea collars are often used as a prevention method. However, sometimes cats can still have itching issues even when using a flea collar. This article will examine some of the potential causes of continued itching and solutions to address it.

We’ll look at questions like: Are fleas actually still present? Is it an allergy or skin irritation from the collar itself? Could it be an unrelated skin condition? Understanding the source of the itching is key to stopping it and keeping your cat comfortable.

How Flea Collars Work

Flea collars contain insecticides that are gradually released onto the pet’s skin and coat to kill and repel fleas. The active ingredients work by disrupting the nervous system of fleas, eventually causing paralysis and death. Some common active ingredients in flea collars include:

Pyriproxyfen – an insect growth regulator that prevents flea larvae from maturing into adults.[1]

Imidacloprid – a neonicotinoid that overstimulates the nervous system of fleas leading to paralysis and death.[2]

Flumethrin – a pyrethroid ester insecticide that attacks the nervous system of fleas and ticks.

The insecticides diffuse from the collar and are distributed over the pet’s skin through their natural oils. The chemicals then accumulate in the pet’s sebaceous glands and hair follicles, creating a reservoir of insecticide on the skin that can kill and repel fleas for several months.

Flea collars are designed to provide continuous protection by slowly and constantly releasing the active ingredients over the course of the collar’s effectiveness, typically 3-8 months. This long-lasting, sustained release of insecticides allows flea collars to control flea infestations without the need for monthly topical treatments.

Reasons a Cat May Still Itch with a Flea Collar

Even with a flea collar, cats may continue to scratch and itch for several reasons:

Infestation Before Application

Flea collars do not kill adult fleas instantly. If a cat already had a severe flea infestation before the collar was applied, it may take days or weeks for the adult fleas to die off. In the meantime, the cat will continue to feel itchy and uncomfortable from existing bites (Source).

New Flea Exposure

Flea collars repel and kill fleas, but they are not 100% effective at keeping new fleas away. If the cat goes outside or is exposed to flea eggs from another pet, it may pick up new fleas that continue to bite and cause itching (Source).

Allergic Reaction

Some cats are allergic or sensitive to ingredients in flea collars. Reactions can cause redness, itching, and discomfort around the neck. Switching to a different brand may help (Source).

Other Parasites

While flea collars target fleas, they do not repel or kill other parasites like mites, lice and ticks that may bite and cause itching. Checking for other parasites and using additional targeted treatments can help (Source).

Treating Flea Allergies

Flea allergies can cause intense itching and discomfort for cats. There are several treatment options to help relieve symptoms:

Anti-itch medication like antihistamines may provide some relief from itching and inflammation. However, antihistamines alone often don’t completely stop the itching (Flea Allergy Dermatitis in Cats).

Corticosteroids can significantly reduce itching and inflammation caused by flea allergy dermatitis. Corticosteroids like prednisolone are often prescribed to give cats immediate relief from intense itching (Flea Allergy Dermatitis in Cats – VCA Animal Hospitals).

Frequent bathing with a gentle shampoo can help soothe skin and wash away flea saliva and waste products that cause irritation. Bathing at least once a week may be needed to provide relief during peak flea season (Flea Allergy).

Cats with severe flea allergies may need more intensive treatment like immunotherapy vaccines or cytokine inhibitor injections. Consulting a veterinarian is important for proper diagnosis and creating a treatment plan for flea allergy relief.

Checking for Fleas

It’s important to thoroughly check your cat’s coat for any signs of fleas if they are still itching, even with a flea collar. According to WikiHow, you can drape a white sheet over your lap and set your cat on it to make fleas more visible. Gently comb through your cat’s fur with a fine-toothed flea comb, especially around the head, neck, and base of the tail [1]. You may see fleas, flea dirt (small black specks), or flea eggs in the comb. PetMD also recommends checking the skin around the tail, armpits, and groin for signs of fleas like redness, inflammation, and flea dirt [2]. Be thorough and patient when combing, as fleas can be difficult to spot. Checking regularly can help determine if fleas are still present so you can take steps to eliminate them.

Eliminating Flea Infestations

To eliminate a flea infestation in your home, you’ll need to attack it from multiple angles. Here are some of the most effective methods:

Use a flea comb – Flea combs can help remove fleas from your cat’s fur. Comb your cat daily and drop any fleas you find into hot, soapy water to kill them.

Vacuum frequently – Vacuuming carpets, furniture, and cat beds at least every 2-3 days can suck up adult fleas and eggs. Be sure to throw away the vacuum bag afterwards so any fleas don’t escape.

Wash all bedding on hot – Wash your cat’s bedding, as well as any blankets or sheets they sleep on, in hot water weekly. The heat will kill flea eggs and larvae.

Use insect growth regulators – Applying insect growth regulators like methoprene or pyriproxyfen around your home can prevent flea eggs and larvae from developing into adults.

Consider professional treatments – For serious infestations, calling a professional exterminator to treat your home may be necessary. They can treat areas like baseboards, carpets, and cracks with insecticides.

With diligent vacuuming, washing, and pest control, you can fully eliminate a flea infestation. Just be patient, as it can take weeks to get rid of all life stages.

Preventing Reinfestation

One of the best ways to prevent fleas from returning after an infestation is by treating all pets in your home. Fleas can live on dogs, cats, and other animals, so leaving one untreated pet can allow the infestation to return. Use flea control products like topical treatments, collars, sprays, powders, or oral medications on every cat and dog in your household according to label instructions (Source).

You’ll also want to treat your home. Vacuum all carpets, rugs, furniture, and floors thoroughly to remove eggs and larvae (Source). Dispose of the vacuum contents in a sealed bag. Use sprays or foggers inside your home according to label instructions, being sure to reach under furniture and in crevices. Treat your yard as well using outdoor sprays or granules.

Wash all pet bedding in hot, soapy water. Consider using flea combs to manually remove fleas and eggs. Be vigilant about checking your cat for signs of reinfestation like excessive scratching. Continue using flea control products as directed to prevent fleas from returning.

Trying a Different Flea Collar

If your cat continues to itch despite wearing a flea collar, trying a different brand or type of collar may help. Some options to consider include:

Seresto Collars – These collars contain flumethrin and imidacloprid as active ingredients. Seresto collars provide 8 months of continuous flea and tick protection. Studies show they are very effective at killing and repelling fleas. See Chewy.com for popular Seresto collar options.

Natural Collars – Some collars contain natural ingredients like citronella, geraniol, and rosemary oil instead of chemical pesticides. These may be a good option for cats with sensitivities. Natural collars usually provide shorter protection, around 3-5 months. Organic Options brand makes a popular natural cat flea collar.

Prescription Collars – Your vet may prescribe an allergy-relief anti-itch flea collar for your cat. These often contain hydrocortisone or other medications to reduce skin inflammation and itching from flea bites. Discuss prescription collar options with your vet if over-the-counter collars aren’t working.

When to See a Vet

If your cat continues itching even after trying flea prevention methods, it’s important to take them to the vet. Severe itching and skin irritation can be signs of an underlying condition that requires medical treatment. Some signs to watch out for that warrant a veterinary visit include:

  • Extensive hair loss or bald patches
  • Oozing sores or scabs from excessive scratching
  • Swollen, reddened skin
  • Frequent head shaking or ear scratching, which may indicate an ear infection
  • Noticeable skin odor, crusting, or greasiness
  • Changes in behavior, such as increased lethargy or irritability

A vet can diagnose the cause of your cat’s itching by performing tests and examining their skin. They may look for evidence of parasites, take skin scrapings, or do allergy testing. Depending on the cause, the vet will prescribe medications to treat infections, recommend flea and parasite prevention products, or develop a desensitization plan for allergies. Providing relief for your cat’s irritated skin and any underlying conditions is important for their health and quality of life.

According to veterinarians, it’s better to have your cat examined sooner rather than later if they develop signs of severe itching, skin irritation, or additional health problems (Source). Addressing the cause and providing medical treatment under veterinary guidance can help soothe your cat’s discomfort.


In summary, there are a few key reasons why a cat may continue to itch even when using a flea collar. The collar may not be killing all flea life stages, the cat could have a flea allergy rather than just an infestation, or there could be an issue with resistance if the same active ingredient is used repeatedly. It’s important to thoroughly check for fleas and eliminate them from the home and pet. Trying a different flea collar active ingredient may help. If itching persists, have your vet examine your cat to identify any underlying problems causing the irritation so it can be properly treated.

The main goal is to identify and address the root cause of your cat’s itching, whether it’s fleas themselves or an allergy. A flea collar alone may not solve the problem. But with vigilance, you can get relief for your cat’s irritating and uncomfortable itching.

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