top of page

What to Do if Your Pet Has Fleas

Fleas are blood-sucking parasites that cause scratching, biting and skin irritation. They are not particular about where their meals come from—if a pet is not available, they will bite a human being. Fleas are unable to live on humans, however. Many dogs and cats exposed to fleas over a period of several months will actually become allergic to flea saliva, resulting in a severe allergic reaction that may be a problem for the rest of the animal’s life. 


Fleas are found everywhere there is warmth and humidity. An adult flea can live up to six months and one female can lay 600 eggs in a lifetime. Starting with only 10 fleas, your house could end up with 90, 000 eggs in only 30 days. 


An adult flea spends only 10 percent of her lifetime on your pet. The rest of the time she is in your pet’s bedding, as well as in your carpeting, draperies, and furniture. To examine your pet for fleas, gently part the hairs at the base of the tail or on the stomach. The fleas will appear as small, brown insects with long rear legs. They will quickly run from the area you are examining, so you may not see any fleas the first time you examine your pet. If none are seen, check for flea droppings, which are tiny, dark brown or black particles that resemble coarsely ground black pepper. These can easily be seen by brushing your pet with a white cloth.


Fleas are difficult to control because the flea life cycle has four distinct stages and no insecticidal treatment is effective on all of the stages. Eggs hatch after one to two weeks into larvae. The larvae can live from one week to seven months. The larvae become encased in a cocoon and are then called pupae. The cocoon provides a very strong physical barrier against insecticides. This stage is responsible for many treatment “failures,” as pupae can survive treatments with most insecticides and may emerge as adults up to one year after forming their cocoon. The egg-to-adult life cycle may be as short as 18 days or as long as 20 months depending on temperature and humidity. 

Flea Control

Effective flea control involves eliminating fleas in the environment as well as on your pet. To do this, all household pets and your entire house and yard must be treated simultaneously. Treatment must be repeated every two weeks for at least two treatments. For an animal that is kept outside, flea control should be used when the temperature approaches 65 degrees F until it drops to freezing or below for one week.

How to Get Rid of Fleas

Products to Purchase

  • Insecticide spray fog—1 can for every 2000 square feet (estimate 100 sq. ft. per bedroom, 250 sq. ft. per living or rec. room and 50 sq. ft. per bed or sofa)


  • Diazanon crystals—For lawn application, available at hardware stores


  • 6 Capstar flea pills


  • Revolution, Frontline, or Simparica flea treatment

Procedure to Get Rid of Fleas


1. Give 1 Capstar tablet to the infected animal and repeat every 7 days, for a total treatment time of 42 days.


2. Apply Revolution, or  Frontline,  to the neck of each animal in the house, or give Simparica chewable.


3. Use Knock-Out spray in your house. 


4. Wash everything associated with the animal in hot water—bed sheets, animal bedding, towels, pillows, etc. You may want to dispose of the pet’s bedding.


5. Vacuum thoroughly, concentrating on areas where your pet spends most of its time, and immediately dispose of the vacuum cleaner bag outside the house.


6. Sprinkle diazanon crystals around the yard where the animal stays. Because fleas can constantly re-infest your pet and therefore your house, yard treatment is very important. Sprinkle the entire area thoroughly, concentrating on areas where your pet likes to spend time.


Repeat the entire procedure in two weeks. 

New Products Make Flea Control Easier

In the last several years, there have been numerous developments in flea control products which make controlling fleas much easier. Each of these products has been developed so you will only need to treat your animal once a month to prevent fleas. All of the products work best when used after a flea bath. 


1. Selamectin (Revolution) is a liquid parasiticide placed between the shoulders of both dogs and cats at monthly intervals. This product is not an insecticide, so it does not have any known toxicities to humans. In addition to killing adult fleas, it also prevents heartworms and kills ticks. Selamectin is available in different strengths, depending on the size of your dog or cat.


2. Fipronil (Frontline/Parastar/EasySpot) is a liquid insecticide that is also applied between the shoulders of your dog. Fipronil kills adult fleas and repels ticks and mosquitoes. It is available in different strengths depending on the size of your dog.


3. Sarolaner (Simparica) is a chewable tablet that is indicated for the treatment and prevention of fleas  and control of tick infestations. 


Note: All four of these products are best used on your pet after a flea adulticide treatment. We recommend the use of Nitenpyram (Capstar). Capstar is an oral flea adulticide. It is extremely effective at killing adult fleas on dogs and cats. It should be repeated weekly for a total of 4 treatments when your pet has fleas. 

Flea life cycle.jpg
  • If one pet in a house has fleas, it can be assumed all pets in the house have fleas, and thus, all pets should be treated. 


  • During its life, the flea spends most of its time off the host, so environmental treatment is vital to winning the war against flea infestation.


  • Besides causing severe itching, fleas can transmit tapeworms and other parasites.

Flea Allergy Dermatitis

Flea allergy dermatitis is a skin disease caused by an allergy to flea bites. An allergy, or allergic response, is an overreaction of an animal’s immune system to a foreign substance (antigen), such as the chemical in flea saliva. In animals with a flea allergy, this defensive overreaction results in swelling, redness, and intense itching that may last for several days after the animal has been bitten. The bite of only one flea is sufficient to trigger this reaction and can cause a serious problem in an allergic animal. In general, flea allergy dermatitis in dogs and cats tends to be more serious as they age. 


An allergic animal scratches, licks, and bites its skin, especially in the lower back and tail area. This intense scratching and biting causes hair loss, crusts, infection of bites, and inflamed, broken skin. In severe cases, large moist areas of very sensitive skin and total hair loss can occur. Flea bites appear as tiny, red bumps in less serious cases. 


Flea allergy dermatitis is treated medically with steroids and/or antihistamines to reduce the inflammation and with antibiotics to control skin infections. The most important, and probably the most difficult part of the treatment, is controlling the flea population in your home. To do this, all household pets, the home, and the environment must be treated simultaneously. The eggs and pupal stages of the flea cycle are difficult to eliminate and are continuously emerging for months. Treatment should be residual in effect and repeated periodically. 

bottom of page