Symptoms and Treatment of Feline Fleas

"Feline fleas is the most common cat skin problem. Even if your cat is an indoor cat, fleas can be transported into the home by people or other pets. They are skilled at hiding ,making detection even more difficult. The parasites can cause disease and other problems such as anemia (low red blood cell counts, lethargy). Flea products are effective and will kill all fleas on your cat. A cat's home or environment will need to be treated as well to ensure that the problem doesn't reoccur or to avoid human bites."

Feline Fleas Overview

Feline fleas is the cause of most cat skin disorders.  When a flea attaches itself to your cat, it injects saliva into the skin. This saliva causes an allergic reaction which results in what looks like red scales. The flea also deposits its eggs into the coat of your cat.

Flea infestations usually occur in warmer months. They cannot survive extreme cold.
Cats younger then 1 year of age rarely suffer from cat fleas.

Problems Caused by Feline Fleas

Feline fleas consume blood the minute they attach themselves to a host (your cat). They can cause iron deficiency and a condition called anemia which is a lower than normal number of red blood cells.

Fleas can also transmit disease into the host such as tapeworm, which is an intestinal disease caused by the worm as it grows.

The most common symptom of flea problems is the skin condition known as flea allergy dermatitis (FAD) which usually results in a condition called feline miliary dermatitis and pruritis (severe itch). Your cat's reaction to the need to itch can cause problems such as scratches. The licking and scratching may cause your cats hair to fall out, a condition called alopecia and a stripe without hair.

Feline Flea and Dermatitis

Dermatitis is a generic name that is applied to any skin problem. Fleas usually cause the formation of a papule which is small solid raised bump covered with a crust.

The bumps are arranged in a pattern which is described as miliary dermatitis.

feline fleas

Picture of Feline Flea miliary Dermatitis

The miliary dermatitis is usually located on your cat's face, neck or back.

Diagnosis of Feline Fleas

If your cat is suffering from fleas in the late summer, then most veterinarians will assume that the cause is fleas. They will look for the presence of the fleas themselves and flea excrement which is small dark pellets called flea dirt. One way to know for sure is to take the pellets and put it in water. If from fleas it should dissolve into a reddish color.

Is is possible that your cat through grooming removed all the fleas, making diagnosis more difficult.You can also try using what is known as a flea comb to check your cat's coat.

There is also a skin test your veterinarian can do to see if your cat tests positive for fleas. There are other conditions that result in dermatitis that is similar to the type caused by fleas. These cat skin problems include parasites such as mites (mange), skin allergy (atopy), bacteria and for causes that cannot be identified.

Treatment of Feline Fleas

The goal of flea treatment is to remove the fleas from your cat and your cat's environment. ONLY PURCHASE PRODUCTS THAT ARE CLEARLY LABELED FOR CATS. For example the ingredient permethrin, which is used in some dog products can be very harmful to cats.

Removing Fleas From Your Cat

Flea products are applied directly to the skin of your cat. It takes 1/2 to 1 and 1/2 days until the flea product spreads and kills all fleas.

The use of only product should be fine since most products today can both kill adult fleas and fleas that are just developing. In the past this wasn't the case.

If you feel the need to use multiple products to cope with a severe infestation, do so only with the advice of a veterinarian or health professional since not all products are safe to use together.

There is also one product that is given orally that works faster (several hours) than the topical types of treatments. This product contains nitenpyram. Flea products called spot-on use the ingredients fipronil, imidacloprid, or selamectin and take 12-42 hours.

One natural approach to killing the fleas that are on your cat is with a herbal flea dip such as Naturasil for Fleas.

If your cat continues to scratch you might want to consider a topical product made to soothe the skin. One product to research is the all natural herbal remedy FleaDerm which is made specifically for flea bite dermatitis.

Feline Flea Treatment and Prevention Products




Frontline, Frontline Plus (topical liquids applied to skin), Frontline Spray


Slow release and resists water. Protects against ticks and adult fleas. Choose Frontline Plus since is protects against adult fleas and has methoprene which is what is called a Insect Growth Regulator to protect against developing fleas and larvae. kills fleas within 24 to 48 hours. Can last as long as 90 days. Not absorbed by bloodstream/non-toxic.

Program - tablet or liquid given 1x per month with a meal

lufenuron, diflubenzuron

Infuenuron builds up in your cats skin. When flea bites it kills the flea. It can take 30 to 60 days for this product to work since it kills fleas that are early in their life cycle. Adult fleas will die naturally. Use in combination with other products like Frontline.

Advantage - used 1x month by applying liquid to cat's skin between shoulders


Works well against fleas. Does not target ticks. Each dose works for 30 days. Kills any flea that comes in contact with skin.Almost all are killed within 12 hours of use. Not absorbed into cats bloodstream/non-toxic. Advantage Multi contains moxidectin to kill heartworm, ear mites and some parasites.

Revolution - applied 1x per month between cat shoulder blades.


This product kills fleas by blocking nerve signals in their bodies. Since this product absorbs into the bloodstream of your cat it protects against heartworm. It also protects against flea eggs, ticks and mites.

Biospot Spot-on Cats - applied to back of head 1x per month.

Pyriproxyfen, nylar

Insect growth regulator that attacks the early stages of the flea lifecycle. Kills adult fleas and ticks. Also kills ticks and mosquitoes. Contains the Insect Growth Regulator (IGR) methoprene to stop immature fleas from developing. Can be a lower cost option for the same protection. Protects your cat for 30 days.

Capstar (oral medication)


Starts killing fleas in 30 minutes after your cat takes the medications. Safe for nursing cats. Only works for 24 hours and can be given often. Follow use with a product like Frontline Plus under advice of a veterinarian.

How to Remove Feline Fleas from your Cat's Environment

Insecticides designed to remove fleas from your cat's environment include methoprene, fenoxycarb and pyriproxifen. An all natural approach to treating your home is called Benzarid.

You should also clean every surface your cat has come in contact with including blankets and sleeping areas. Fleas can live in areas around your house. Be sure to vacuum thoroughly and treat all areas of the home.

Areas where your cat has walked are particularly important since fleas and eggs could drop from your cat.

Can Cat Fleas Bite Humans?

Cat fleas prefer cats as their host. However, to live, adult fleas need to drink in either pet or human blood. If the flea cannot find a pet as host, they will attach to a human. 

Signs of human flea bites are usually on the lower parts of the body where the flea attempted to bite after leaping up from the ground. This includes small, red itchy areas around the feet and ankles.

It is possible that fleas transmit diseases to humans that are troublesome for individuals whose immune system is not working properly. Also if the fleas infected your cat, and your cat scratches you, it is possible to get a disease called Bartonella which is more commonly called cat scratch disease. This disease is also only a problem in individuals with a compromised immune system.


The Merck/Merial Manual for Pet Health

Update on the Diagnosis and Treatment of Fleas and Mites
Prof. Dr. Ralf S. Mueller, DipACVD, FACVSc, DipECVD, FAAAAI
Medizinische Kleintierklinik, Ludwig-Maximilian-University Munich, Germany


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