UNIVERSITY OF CALIFORNIA, DAVIS
VETERINARY MEDICAL TEACHING HOSPITAL
DAVIS, CA 95616
SMALL ANIMAL CLINIC: 530-752-1393
DERMATOLOGY SERVICE
Information for Clients
FLEAS AND FLEA ALLERGY DERMATITIS
The adult flea spends most of its time living on cats and dogs. Fleas lay eggs on the animals,
but these eggs rapidly fall off the pets and are distributed in the parts of the environment
where the pets spend most of their time. The eggs hatch into larvae which evolve into
pupae (cocoons) emerging in the future as adult fleas. For one adult flea found on your pet
there are at least one hundred immature fleas in the animal's environment.
Flea allergy is the most common cause of itching and scratching in the dog and cat. When
the flea bites your pet, it injects a small amount of saliva into the skin. Dogs and cats can
develop an allergy to this saliva and will react to it with severe itching and scratching. This
itching sensation may last for up to two weeks after the last flea bites.
In the dog, the most commonly observed signs of flea allergy are biting and scratching around
the rump, tailbase, and groin area; "hot spots;" and secondary skin infections. Cats may
manifest flea bite allergy more subtly. You may see areas of hair loss and scratching, but
more often you will feel small scabs and bumps around their neck and down their backs
(commonly known as miliary dermatitis).
It may seem confusing to you to be told that your dog or cat has flea allergy dermatitis if you
never see fleas. This is mainly due to the fact that your pet has a remarkable capacity to
either scratch, lick or chew the fleas off. You may also find evidence of fleas on your pet by
using a fine comb and brushing out the "flea dirt" that they leave behind. This "dirt" looks like
small black dots, and is the excrement of the flea. When placed on wet paper, it dissolves in
red streaks because it contains partially digested blood.
The only long term efficacious and safe therapy for flea allergy dermatitis is to keep your pet
from being bitten by fleas. Remember, successful resolution of the flea allergic animal's
misery requires that the fewest possible number of fleas bite your pet.
RECOMMENDATIONS FOR FLEA CONTROL
The control of fleas is an ongoing process, but once initiated, it is not difficult to sustain. The
following recommendations will assist you in this control, but you should remember that they
are simply guidelines to follow. The flea control program you use must be tailored to you and
your pets individual situation. Just as we are constantly updating our protocol, it is necessary
for you to change yours as new products become available and the efficacy of those now in
use are altered by time of year, location, and reformulation.
The products listed in this handout are some of those which the VMTH carries in its
pharmacy. We do not endorse any particular brand name product; our intention is to
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recommend a specific active ingredient for use and we use the brand name products that we
stock as examples.
FLEA CONTROL ON YOUR PET
Dogs: (1) We recommend the use of an adulticide product (a product that kills the adult
fleas) for all dogs and cats in the households. The newer veterinary “spot-on”
products offer both safety and convenience. These products have been shown to be
very effective when used as instructed and are not absorbed into your pet’s
bloodstream (they stay in the skin) making them very safe.
Advantage®
(imidacloprid), Frontline Plus® (fipronil and methoprene) and K9Advantix™
(imidacloprid and permethrin) are currently available at the VMTH. Accurate dosage
is based on the pet’s weight. These products are applied by parting the hair between
the shoulder blades and down the back, applying the small amount of liquid directly
onto the skin (not on the hair). Application frequency varies with the product and
bathing needs. These products are most often applied every 2-4 weeks. It is
recommended that you apply the spot-on treatment 1-2 days after bathing and avoid
bathing in between applications. Depending on the product, fleas contacting your pet
will die within 12-36 hours after exposure to the spot-on product. Advantage® can be
safely used on puppies 7 weeks of age and older. Frontline Plus® is also effective
for the brown dog tick and can safely be used on puppies older than 8 weeks.
K9Advantix™ also is effective against ticks and can be used safely on puppies 7
weeks of age and older. K9Advantix™ contains permethrin which IS TOXIC FOR
CATS and cats should NOT come in contact with this product.
Revolution® (selamectin) and Advantage Multi® (imidacloprid and moxidectin) are
“spot on” products that are absorbed into the body. Both of these products are
effective against heartworms and a variety of intestinal parasites as well as fleas.
Revolution® is safe to use on puppies and kittens over 6 weeks of age, Advantage
Multi® is safe to use on puppies and kittens 7 weeks of age and older.
Oral flea adulticides, Capstar® (nitenpyram), Comfortis™ (spinosad), NexGard™
(afoxolaner) and Bravecto™ (fluralaner) are also available. Capstar® is a very safe,
short acting oral tablet which can be given daily to every other day for routine flea
control, or used concurrently with other products. Capstar® is safe to use daily, or
can be used as a “rescue” drug to kill fleas should they be seen on dogs and cats
older then 4 weeks of age and at least 2 pounds of body weight. Capstar® begins
working within minutes and kills fleas immediately after the first blood meal is taken.
Comfortis™ is a chewable flavored tablet approved for use in dogs and cats, 14
weeks of age and older. Comfortis™ achieves full effectiveness within 4 hours and
kills fleas after the first blood meal is taken. Comfortis™ should be administered
every 2-4 weeks with a full meal. The active ingredient in Comfortis™, spinosad, is
also available as a combination heartworm and intestinal parasiticide product know
as Trifexis™. Trifexis™ contains milbemycin in addition to the spinosad and, like
Comfortis™, should be given with a full meal. NexGard™ is a flavored chew for use
in dogs and puppies 8 weeks and older. This product kills adult fleas and the
American Dog tick (Dermacentor variabilis). NexGard™ should be administered
once monthly. Bravecto™ is a flavored chewable tablet for dogs 6 months of age
and older and 4.4# and larger. Bravecto™ begins killing fleas and ticks within two
hours and achieves full effectiveness within 12 hours. Bravecto™ is administered
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every 3 months with food and is labeled for control of fleas and ticks (Dermacentor
variabilis – American Dog Tick, Ixodes scapularis – Deer Tick, and Rhipicephalus
sanguineus – Brown Dog Tick). All of these products are oral, systemic products and
therefore not affected by bathing or swimming.
More recently available is a flea control collar that is safe and effective for dogs and
cats. The Seresto™ collar contains flumethrin and imidacloprid and is safe to use on
dogs 7 weeks of age or older and cats 10 weeks of age or older. The Seresto™
collar kills fleas and ticks for up to 8 months.
Three other veterinary products available for dogs are Vectra 3D™ (dinotefuran,
permethrin and pyriproxyfen), Certifect™ (fipronil, methoprene and amitraz) and
Parastar™ Plus (fipronil and cyphenothrin). The VMTH is not yet carrying these
products, but they may currently be available through your local veterinarian or at the
VMTH in the future. Vectra 3D™ is a spot-on product safe for use on dogs and
puppies 7 weeks of age and older. This product kills and repels fleas, ticks and
mosquitoes, and its third product, pyriproxyfen, is an insect growth regulator which
prevents development of flea eggs and larva. Vectra 3D™ is recommended for
monthly application. Certifect™ for dogs is another topical spot on product safe for
dogs and puppies, 8 weeks of age and older. Certifect™ for dogs kills fleas and ticks
and contains methoprene an insect growth regulator which prevents development of
flea eggs and larva. Parastar™ Plus kills fleas and ticks on dogs and puppies 12
weeks of age and older. Certifect™ and Parastar™ Plus are also recommended for
monthly application. All three of these products contain ingredients that are TOXIC
TO CATS and cats should never come in contact with these products.
Cats:
(2) If you own cats, they must be involved in the flea control program even if they are
not exhibiting any problems, or they will carry the fleas to your house, yard, and dogs.
Cats are more sensitive to the chemicals in flea preparations, and many insecticides
can not be used on them. For cats, we recommend using either Revolution®
(selamectin), Frontline Plus® (fipronil and methoprene), Advantage® (imidacloprid),
Advantage Multi® (imidacloprid and moxidectin) or Cheristin™ (spinetoram) in the
feline formulation. Another product not currently available at the VMTH is Vectra™
(dinotefuran and pyriproxyfen) for cats. All these products are applied in a similar
fashion as in dogs. Beginning at the base of the head, part the hair and apply the
small amount of liquid to the skin (not the haircoat) along the back of the neck.
Application also varies from two to four week intervals, depending on other
treatments.
Please follow the instructions outlined for your pet.
Capstar®
(nitenpyram) is also safe for use in cats as a “quick kill” in the event fleas are seen, or
can be given every one to three days for routine flea control if an oral product is
desirable.
Juvenile Flea Stages:
There are several life stages that occur before a flea becomes a biting adult. Some of these
juvenile stages are also targets for flea control. Decreasing the numbers of immature
(juvenile) fleas can be an excellent way to help prevent adult fleas and thus flea bites.
Research has led to the release of several products that interrupt the life cycle of the flea.
Often these products are used in combination to quickly and effectively decrease the flea
burden of your pet. Synthetic juvenile flea growth hormone imitators are found in many flea
products. Methoprene (Precor®) is contained in Frontline Plus® and Certifect™ as well as
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many of the indoor area treatments. Vectra 3D™ contains pyriproxyfen as one of its active
ingredients. All of these synthetic hormones are very safe to use on animals and around
humans. They prevent the adult female flea from laying viable eggs and prevent immature
fleas from developing into adults.
Program® (Lufenuron) is an oral chewable tablet available for both dogs and cats that is
given monthly with food. As the adult female flea feeds on the dog or cat, the female flea
lays eggs that cannot hatch and larvae that will not survive. This product is very safe, but
flea-allergic animals also need protection from the biting adults. Program® is best used in
combination with a topical or oral flea adulticide. Another formulation available is lufenuron in
combination with milbemycin, a monthly heartworm preventative. This product, called
Sentinel® is also given monthly with a full meal.
Most other forms of flea control on your pet have been scientifically shown to be ineffective.
Flea shampoos will only kill the adult fleas but have virtually no residual effect, and will not
prevent reinfestation once they are rinsed off. Electronic flea collars, brewer's yeast, garlic,
vitamin B tablets, and extracts of eucalyptus or pennyroyal, are not flea repellent, and provide
no protection for your pet. Lastly, flea combs, although helpful, are similar in effect to the use
of flea shampoos alone; they do not prevent reinfestation.
SIGNS OF TOXICITY
All flea control products are potentially toxic or may produce unexpected side effects. Toxicity
may result from accidental overdose or unexpected sensitivity. Known side effects, although
rare, are vomiting, diarrhea, drooling, sluggishness, weakness, or abnormal behavior. If you
suspect that your animal is reacting adversely to a flea control product, stop using the
product and consult your veterinarian immediately. If the reaction occurs immediately after
application, the product should be rinsed off thoroughly and the animal brought to the
veterinarian for evaluation. Adverse reactions may occur from minutes to days following
application. Insecticides can be toxic to people; all products should be handled carefully,
avoiding direct contact as much as possible. Keep all products out of the reach of
children. Cats are particularly sensitive to many pesticides. ONLY USE PRODUCTS
LABELED TO BE SAFELY USED ON CATS. If you have any questions about a product’s
safety, please consult your veterinarian.
FLEA CONTROL IN YOUR ENVIRONMENT
Immature life stages of the flea accumulate in the environment when animals with fleas serve
to disperse flea eggs into the environment where they then hatch into juvenile life stages.
House and yard treatments need to be concentrated on "source points", which are areas
where your pets spend most of their time. This typically would include the bedding and
resting areas, the feeding location, etc. You can lessen the flea burden in your home by
thorough vacuuming of all source points followed by disposal of the vacuum bag and by
washing all animal bedding weekly in hot water and drying at high heat for twenty minutes.
Steam cleaning of rugs and carpeting +/- upholstery is also helpful.
In the yard, focus on areas where your pet(s) or other animals spend most of their time.
Typically, fleas survive and reproduce in shaded, moist areas with plant or organic debris
(under decks, bushes, storage sheds, etc). Fleas do not survive or reproduce well in sunny,
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open areas of lawn or patio. Elimination of yard debris will be helpful in reducing flea
numbers. You may choose to utilize a professional exterminator service for the treatment of
fleas in your home and garden.
REALISTIC EXPECTATIONS
It is important to realize that the various anti-flea medications do not eliminate the immature
forms of fleas in the environment. Thus, for the first month or so you may continue to see
fleas on your pet as the juvenile forms mature and search for a new host. This does not
mean that the fleas have built up resistance to the medication – in reality, flea resistance to
these products is quite rare. The most common reasons for failure to control a flea problem
are:
1. Frequent washing of a pet treated with a spot-on product (this includes swimming in pools,
lakes or the ocean).
2. Inconsistency in the application of the product.
3. Failure to treat all pets.
4. Wildlife reservoirs of fleas (feral cats, raccoons, opossums, coyotes, etc.). Thus areas
below outside decks, old sheds, etc. should be barricaded or locked to discourage such
‘visitors’.
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