Canine Flea Infestations

The flea is a common problem for dogs as well as their owners. As if flea bites aren’t bad enough, some pets are “flea allergic” and develop severe itching with even trivial infestations of fleas. This occurs because the animal becomes hypersensitive to the antigens in flea saliva.

The itching component to flea allergy can be treated with antihistamines or even steroids (prescribed by your veterinarian) but the best approach is to kill the flea and prevent its return. Like all parasites, fleas pose a health-hazard to your pet (and to you), and can make him miserable. These worrisome pests can be treated and prevented.

Fleabite hypersensitivity or “flea allergy” can occur in any breed with the average age of first occurrence being three to six years. There appears to be no sex predilection. Fleas are typically seasonal in Northern climates and non-seasonal (year-round) in Southern climates.

What to Watch For

Itching, chewing and licking

Flea “dirt” (black pepper type discharge on the skin)

Skin lesions such as moist dermatitis

Presence of fleas

Diagnosis of Flea Infestation in Dogs

Diagnostic tests may not be needed to recognize fleas but they may be important to determine if flea-associated illness is occurring. Tests may include:

Complete medical history and physical examination. Fleas can usually be diagnosed based on the history and physical examination. Flea combing helps to find fleas or flea “dirt.”

Fecal examination for tapeworm eggs, which can be secondary to flea infestation, may be recommended.

Treatment of Flea Infestation in Dogs

Treatment for fleas may be dependent on the following: the degree of infestation; whether you have both cats and dogs; the time of the year; area of exposure (yard vs. park); and whether your pet has an allergy to the fleas.

Recommendations may include the following:

Many products are available for the treatment of flea infestations. All products have advantages and disadvantages and may or may not be safe to use with other products. Some of the over-the-counter powders, sprays and collars (such as Hartz® or Sargeant’s® products) contain pyrethrin, which is moderately effective. However, the best flea products are obtainable only with a prescription.

In tough cases, a comprehensive flea control program may be needed that involves treatment of your pet, yard and house.

Home Care and Prevention

Optimal treatment for your pet requires a combination of home and professional veterinary care. Follow-up is important especially in cases of flea allergic pets. Make sure to administer all veterinary prescribed medications and follow preventative recommendations.

Be certain to contact your veterinarian if you are experiencing problems treating your pet or the environment. Some microscopic eggs can live in the environment like the yard for weeks to months and cause re-infection. If your yard has a severe infestation, use products recommended by your veterinarian.

Minimize roaming in places like parks and fields where exposure and infection are possible. Minimize contact with rabbits, rodents and/or fleas to minimize exposure to tapeworms.

Monitor all pets in your household for evidence of fleas on a regular basis. Use a flea comb to check for fleas. A flea comb is a comb with very fine teeth that will catch the flea as you comb, giving you evidence of its presence.

Flea prevention is recommended when there is a reasonable chance of flea infestation or in a flea-allergic pet living in an area infested by fleas. Products, such as Program® (lufenuron), are popular for this purpose; they prevent development of fleas that attack your pet. With few exceptions, these are far more effective than most collars or tags.

In-Depth Information on Flea Infestation in Dogs

Below is some in-depth information on the diagnosis and treatment of flea infestations in dogs. 

Diagnosis In-depth of Canine Flea Infestation

Fleas are a common cause of itching and scratching in dogs; however, other medical problems can lead to similar symptoms.

Other skin disorders can cause similar signs of flea infestation and should be ruled out before appropriate treatment can be given. Some disorders include: food allergy, atopy (hereditary allergy), trauma or other cause of local skin irritation, sarcoptic mange, cheyletiellosis, ear infections and primary keratinization defects.

Remember that many pets may have more than one problem. For example, in some dogs, scratching due to fleas can cause a skin sore which becomes infected with bacteria.

Diagnostic tests are often performed to confirm the diagnosis of fleas and exclude other diseases that may cause similar symptoms. A complete medical history can often help differentiate fleas from other causes of skin disease. Be prepared to answer the following questions:

Does your pet itch?

Which areas of the body does he/she scratch or chew?

Is there a prior history of skin problems?

Has there been a response to therapy?

Does your pet have any concurrent medical conditions?

In addition to a medical history, a complete physical examination will be performed, including a thorough examination of the skin.

Additional tests may include:

Fecal analysis can be performed to determine the presence of concurrent gastrointestinal (stomach or intestine) parasites or the evidence of tapeworms (which are transmitted via fleas).

Complete blood count (CBC) and blood biochemistry tests may be indicated if symptoms are recurrent or there are signs of another illness.

Skin scrapings may be done to determine the presence of mites (mange).

Allergy testing with radioallergosorbent test (RAST) and/or the enzyme linked immunosrobent asay (ELISA) are sometimes used. These tests have variable accuracy.

Intradermal allergy testing to identify the cause of the allergy (most flea allergic pets will react to the flea antigen).

Ear slide/cytology may be recommended to evaluate for mites or infectious organisms.

Treatment In-depth of Canine Flea Infestation

Treatments for fleas will depend on the following:

The degree of infestation

Whether you have both cats and dogs

The time of the year

Area of exposure (yard vs. park)

Whether your pet has an allergy to the fleas

Prescription flea control products are superior and include prevention products such as Program® (lufenuron) that prevent development of fleas that attack your pet and topical treatments that both kill and prevent fleas and ticks. Some topical treatments include Frontline® (fipronil) and Advantage® (imidacloprid). The new topical treatment, Revolution® (selamectin), prevents fleas, heartworms and some intestinal parasites.

If your pet already has fleas, then you need to kill them first with a product like Capstar® (nitenpyram), Frontline® or Advantage®. Capstar® is an oral tablet that will result in flea death within 4 hours after administration.

Local and regional needs and recommendations vary and there are a number of excellent product options. There are new and better products available all the time, so see your veterinarian for current recommendations. In difficult cases, a comprehensive flea control program may be needed requiring treatment of the pet, yard and house.