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Canine Sarcoptic
Mites
and Mange
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SARCOPTIC MITES and DEMODEX
MITES are often referred to as MANGE. The word mangy describes a
ragged
and 
uneven hair coat and damaged skin that results from mites
affecting the skin and hair follicles. Mange is responsible for many
annoying and persistent problems in veterinary dermatology. Demodex mites in
general are less troublesome than Sarcoptic mites, cause less itching
and self-mutilation, and are not seen in adult dogs as often as
Sarcoptic mites. The mite known as SCABIES, SARCOPTIC MITES
or SARCOPTIC MANGE are highly communicable little bugs that
actually dig tiny tunnels into the skin
where they cause intense itching, inflammation and hair
loss. Many, many cases of skin itching (called “pruritus”)
in dogs and cats have
been diagnosed by veterinarians as “Allergic Dermatitis” when in fact
the pet had sarcoptic mites. (See the article called ITCH AND SCRATCH).
The difficulty lies in the fact that Sarcoptic Mite infestation really
does look like an allergic dermatitis because the skin is reacting to
an irritant... just like an allergy! The intense itching results
in self
trauma, hair loss, and dry crusty skin lesions. In some cases the
dog or cat can lose large areas of fur and literally be covered with
crusts
and scabs. Scabies mites can affect humans, as well. A
swift
diagnosis of sarcoptic mites is vital to the pet’s health and the well
being of the pet’s owner. Generally, in healthy humans who are
not
immune suppressed, the Scabies Mites do not reproduce very readily and
may
simply “go away” without medical treatment. If you are in doubt
about
human cases of Scabies, consult your physician.
| A SIMPLE WAY TO PRESUME THE
DIAGNOSIS OF SCABIES IN DOGS
In over 95% of dogs with Sarcoptic Mite
infestation (Scabies) a simple test can suggest that these mites are
present. It is called the Pedal-Pinna Reflex Test. Since
almost all dogs with Scabies mites will have mites along the ear flap
(called the Pinna) margins, as displayed in some of the
photos below, the dog will reflexively use a back leg in a scratching
motion if the Pinna is scratched gently by a person testing this
reflex. Simply take the Pinna between your thumb and forefinger
and vigorously scratch the surface of the underside of the Pinna with
the forefinger. Dogs with no mites seldom work the back leg in a
scratching motion. Dogs with sarcoptic mites almost always will
demonstrate an involuntary scratching motion with the back leg while
you are scratching the Pinna.
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A further unfortunate
happenstance with the misdiagnosis is that far too often veterinarians
will quickly reach for the cortisone, for example Prednisone, as
a way of combating the effects of the “Allergic Dermatitis”. The
cortisone is not a cure...
it simply lessens the itching and scratching and the dog or cat feels
more
comfortable. The danger here is that IF the pet really has
scabies
mites and NOT an allergic dermatitis, the mites welcome the cortisone
with
open arms... er, ah... I mean legs! And they have eight of ‘em!
The
cortisone allows the sarcoptic mites to reproduce more rapidly and
decreases
the dog or cat’s ability to defend against the mites. The mites
have
a reproductive festival after cortisone products are administered.
Some veterinary schools who accept referrals to their dermatology
specialists will not accept a pet for allergy testing until a trial
treatment
of Ivermectin medication is used first. Then, if the pet is still
itching and scratching after a few weeks trial period, they will
consider
examination the dog or cat for allergy testing and treatment.
That’s
how common it is for Sarcoptic mites to be mistaken for Allergic
Dermatitis...
the specialists want mites to be ruled out first before they begin
allergy testing. There is a new product, described below,
available to your veterinarian from Pfizer Animal Health that may be an
excellent medication for the treatment of Sarcoptic Mites.
What is
Ivermectin?
NOTE: Some veterinarians believe that Ivermectin should NOT
be used in Collies, Shelties and other herding breeds. Thoroughly
discuss the use of Ivermectin in herding breeds with the veterinarian
before using this product in these breeds and consider alternate
therapies
if there is any uncertainty regarding the safety issue.
This amazing chemical has been used for years as a large animal (farm
animal) dewormer. It is also the active ingredient in the famous
Heartworm preventative called Heartgard. Scientists and
practitioners
found out that if used IN THE CORRECT DOSE, Ivermectin, either injected
or given orally, can kill sarcoptic mites! This is a fabulous
discovery
since dogs no longer have to endure chemical dips and sprays to
eliminate
scabies mites. The Ivermectin, IN THE CORRECT DOSE, can
successfully
treat dogs for sarcoptic mites.
Now... here’s the downside: Some dogs have a genetically
determined sensitivity to Ivermectin!
FROM THE WASHINGTON STATE UNIVERSITY VETERINARY SCHOOL website: It is well known that
Collies and related breeds can have adverse reactions to drugs such as
ivermectin, loperamide (Imodium®), and others. It was previously
unknown why some individual dogs were sensitive and others were not.
Advances in molecular biology at the Veterinary Clinical Pharmacology
Laboratory at Washington State University's College of Veterinary
Medicine have led to the discovery of the cause of multi-drug
sensitivity in affected dogs. The problem is due to a mutation in the
multi-drug resistance gene (MDR1). This gene encodes a protein,
P-glycoprotein, that is responsible for pumping many drugs and other
toxins out of the brain. Dogs with the mutant gene can not pump some
drugs out of the brain as a normal dog would, which may result in
abnormal neurologic signs. The result may be an illness requiring an
extended hospital stay--or even death.
A test has recently been developed at Washington State University
to screen for the presence of the mutant gene*. Instead of avoiding
drugs such as ivermectin in known susceptible breeds, veterinarians can
now determine if a dog is normal, in which case the drug can be
administered or abnormal, in which case an alternative treatment can be
given. Owners and breeders can submit samples for testing. All
that is needed for the test is a cheek brush sample that can be
obtained by the owner and sent by mail for analysis.
Affected Breeds
Approximately 3 of every 4 Collies in the United States have the mutant
MDR1 gene. The frequency is about the same in France and Australia, so
it is likely that most Collies worldwide have the mutation. The MDR1
mutation has also been found in Shetland Sheepdogs (Shelties).
Australian Shepherds, Old English Sheepdogs, German Shepherds,
Long-haired Whippets,
Silken Windhounds, and a variety of mixed breed dogs.
The only way to know if
an individual dog has the mutant MDR1 gene is to have the dog
tested. As more dogs are tested, more breeds will probably be added to
the list of affected breeds.
Ivermectin is not approved to be used in this manner. So your
veterinarian should let you know this prior to getting your permission
to utilize Ivermectin therapy in the treatment of scabies in dogs and
cats. You can retain some confidence to know that it is in common
usage, and
has been for a number of years, for the treatment of scabies in
pets. It simply has not been tested by the manufacturer and
approved by the FDA to be used in this manner. You are on your
own, you and your veterinarian, in the decision-making arena regarding
whether or not to use it to treat sarcoptic mites. Your
alternative is to use insecticide dips and sprays. Additionally,
if the wrong dosage is given, the pet can have a very serious and even
fatal reaction to Ivermectin.
The correct dose MUST be given and great care taken not to give too
much.
All pets in contact with an affected animal should be treated since
there can be asymptomatic carriers (they have the disorder but aren’t
showing any signs of disease) of the sarcoptic mites. Pfizer Animal
Health
has released a new product called Revolution that is approved for use
on dogs for the elimination of Sarcoptic mites. Be sure to ask
your
veterinarian about this.
There are a number of treatments available to eliminate Sarcoptic
Mites from dogs and the veterinarian will decide which may be best for
each individual case. All dogs with scabies mites need to be on
a high quality, meat-based diet... and many will benefit from
supplements
such as Vitamins and Fatty acids. See PetFoodDirect.com for home
delivery
of skin specific supplements and Vitamins... plus an excellent
breakdown
of many pet diets and their ingredient lists.
If your dog is being treated over and over
(unsuccessfully) for "allergies" with cortisone products and has never
had Sarcoptic Mites actually ruled out as a possible cause of the skin
condition, ask your
veterinarian about the advisability of a trial treatment for scabies...
just in case.
Click to enlarge the images below
that show actual cases of sarcoptic mites
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Scabies on the elbow of a dog
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Same patient, more skin lesions
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Click to enlarge the
images below that show actual cases of sarcoptic mites
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Ear margins are common
sites for sarcoptic mite infestation
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Damaged pinna due to long
term sarcoptic mite infestation
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Notches seen in damaged
pinna due to long term sarcoptic mite infestation
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Elbow and lower front
limb skin lesions
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Another ear lesion
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More photos of ear problems from Sarcoptic mites
(scabies) in a dog...
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Quite commonly the ear margins
are the most notably affected places the sarcoptic mites choose to
damage. The ear tips and edges are very pruritic (itchy), develop
crusts, dry out and bleed. Fly bite lesions are often similar but
the hallmark of
scabies is itchiness. Scabies, though, may affect any area of the skin.
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Many types
of dermatological problems are avoided if the dog or cat is consuming
an optimum diet. In some cases, adding a supplement such as
DermCaps, a popular Omega
Fatty Acid supplement with a number of beneficial ingredients, is
the key factor in avoiding
repeated episodes of Hot Spots and other skin afflictions. If
your
dog or cat seems to lack good coat and skin health, consider upgrading
the diet to a meat-based ingredient formula and adding a supplement
such
as DermCaps.
reprinted with kind permission from Dr Dunn
http://www.thepetcenter.com
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Demodectic Mange
Becky Vaughan-Curran
Garwood Kennels
http://www.garwoodkennels.com
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Demodectic Mange on dog's foreleg
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Canine
Demodicosis is commonly known as Demodectic Mange which is caused by
the Demodex Mite. The mite normally resides in the animals hair
follicles in small numbers. There are two types of Demodectic;
Localized Demodicosis usually occurs in 3 to 10 month old puppies. It
consists of small patches in which well defined scaly areas of hair
loss occur around the dog's lips, eyes, and/or forelegs. The second
type, Generalized or Pustular Demodectic is more severe and extremely
difficult to cure or control. Small patches appear, in which well
defined scaly areas of hair loss spread rapidly over large areas of the
body. This is accompanied by extreme itching, edema, and bleeding
followed by invasion of bacterial infection. Generalized Demodicosis is
caused by a hereditary genetic defect in which the 'T'-cell that
normally controls the mite is
weakened or nonexistent, allowing the mite to multiply in large
numbers.
Demodex Mite
The mites usually spend their entire life on a dog. The female mite
burrows into the skin and lays eggs several
times as
she continues burrowing. These tunnels can actually reach the length of
several centimeters. After she deposits the eggs, the female mite dies.
In 3-8 days the eggs hatch into larvae which have 6 legs. The larvae
mature into nymphs which have 8 legs. The nymph then molts into an
adult
while it is still in the burrow. The adults mate, and the process
continues.
The entire life cycle requires 2-3 weeks. The mites prefer to live on
the
dog but will live for several days off of the host in the environment.
In
cool moist environments they can live for up to 22 days. At normal room
temperature in a home they will live from 2 to 6 days. Because of the
mite's ability
to survive off the host, dogs can become infected without ever coming
into
direct contact with an infected dog.
reprinted with kind permision from Becky
Vaughan-Curran
Garwood Kennels, Garwood Web Design, CKC member, AWCA member
www.garwoodkennels.com
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The above information is simply
informational. It's intent is not to replace the advice of a
veterinarian nor to assist you in making a diagnosis of your pet.
Please consult with your own veterinarian for confirmation of any
diagnosis. Your pets life may depend on it.
