Sarcoptic
Mange
(ALSO CALLED SCABIES)
THE ORGANISM AND HOW IT LIVES
Sarcoptic mange is the name
for the skin disease caused by infection with the Sarcoptes scabei mite.
Mites are not insects; instead they are more closely related to spiders.
They are microscopic and cannot
be seen with the naked eye.
Adult Sarcoptes scabei mites live 3 to 4 weeks in the host’s skin. After
mating, the female burrows into the skin depositing 3 to 4 eggs in the tunnel
behind her. The eggs hatch in 3 to 10 days producing a larva which, in
turn, moves about on the skin surface eventually molting into a nymphal
stage and finally into an adult. The adults move on the surface of the skin
where they mate and the cycle begins again with the female burrowing and
laying eggs.
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Sarcoptes
Scabei: Female sarcoptes mite burrowing in the skin and leaving a trail
of eggs behind her. Her presence generates an inflamatory response in the
skin similar to an allergic response.
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APPEARANCE OF THE DISEASE
The motion of the mite in and on the skin is extremely itchy. Further,
the presence of mites and their eggs generates a massive allergic response
in the skin which is even more itchy.
Mites prefer hairless skin thus leaving the ear flaps, elbows and abdomen
at highest risk for the red, scaley 
itchy skin that characterizes sarcoptic mange. It should be noted that
this pattern of itching is similar to that found with airborne allergies
(atopy) as well as with food allergies.
Dog with dematitis problem typical of sacrcoptic mange. Note: Many dogs
do not develop the classical ear margin crusts until later in the disease.
Frequently, before attempting to sort out allergies, a veterinarian
will simply treat a patient for sarcoptic mange as a precaution. It is
very easy to be led down the wrong path (pursuing allergy aggressively)
if one considers sarcoptic mange an unusual or unlikely possibility.
As the infection progresses, eventually most of the dog's body will
be involved. Classically, though, the picture begins on the ears (especially
the ear margins), the elbows, and abdomen.
The term scabies refers to mite infestations by either Sarcoptes scabei
or other mite species closely related to Sarcoptes scabei. While Sarcoptes
scabei can infect humans and cats, it tends not to persist on these hosts.
When people (including some veterinarians) refer to sarcoptic mange or
scabies in the cat, they are usually referring to infection by Notoedres
cati, a mite closely related to Sarcoptes scabei. In these feline cases,
it would be more correct to refer to notoedric mange, though the treatment
for both mites is the same. Notoedric mange, in cats, generally produces
facial itching and scabbing.
DIAGNOSIS
When an animal with sarcoptic mange scratches itself, it breaks open
the tunnels that the mites have burrowed into and the mites are killed (though
the itch persists due to toxins in the skin). The result is that the mites
can be very difficult to confirm by skin scraping tests. (Probably mites
are confirmed in 50% or fewer of sarcoptic mange cases.)
Since negative test results do not rule out mite infection, a "maybe
mange" test is frequently performed. This consists simply of treating for
sarcoptic mange and observing for resolution of the signs within 2 to 4
weeks.
Of course, if mite presence is confirmed by skin scraping, then one
knows immediately the cause of the itching and need not be concerned about
allergy possibilities or other diseases and the condition can be addressed
with confidence.
BIOPSY - Mange mites are rarely seen on a skin biopsy sample,
though, if the sample is read out by a pathologist who specializes in skin,
the type of inflammation seen in the sample can be highly suggestive of sarcoptic
mange. This is an example of a skin disease where it makes a difference whether
the pathologist reading the sample specializes in reading skin samples.
TREATMENT
While sarcoptic mange is difficult to diagnose definitively, it is fairly
easy to treat and a number of choices are available.
DIPPING - Anti-bacterial or anti-itch shampoos preceed one of
several anti-mite dips. Paramite dip (an organophosphate), Mitaban dip (Amitraz),
and Lime-Sulfur dips given weekly are usually effective. Disease typically
resolves within one month. Dips are often used in combination with one
of the other treatments listed below.
IVERMECTIN- This is one of the most effective treatments against
Sarcoptes scabei yet it is off-label as far as the FDA is concerned.
Typically an injection is given either weekly or every two weeks for a
total of 1 to 4 doses. In most cases this treatment is safe and effective
but some individuals have a mutation that makes ivermectin very toxic at
the doses used to kill mites. These individuals are usually of the
Collie family but other individuals may be affected. For this reason,
use an approved treatment such as Selamectin (see below).
There is now a DNA test that can determine if any dog has the mutation
that makes ivermectin use dangerous. This test is done at Washington State
University. For more information, visit www.vetmed.wsu.edu/vcpl.
SELAMECTIN (REVOLUTION®) - Selamectin is an ivermectin derivative
recently marketed for the control of fleas, roundworms, hookworms, ticks,
ear mites and sarcoptic mange mites. Normal monthly use of this product
should prevent a sarcoptic mange problem but to clear an actual infection
studies show an extra dose is usually needed after 2 weeks for reliable results.
This product is probably the best choice for Collie or Australian shepherd
breeds.
ALL DOGS IN A HOUSEHOLD WHERE SARCOPTIC MANGE
HAS BEEN DIAGNOSED SHOULD BE TREATED.
MILBEMYCIN OXIME (INTERCEPTOR® OR SENTINEL®) - Milbemycin
Oxime is approved for heartworm prevention as a monthly oral treatment.
Happily, it also has activity against sarcoptic mange and several protocols
of varying success have been recommended by different dermatologists. This
is another medication that one might find recommended.
For more information
from the manufacturer, visit their page for Interceptor:
HOW THE INFECTION IS SPREAD
Sarcoptic mange mites are usually spread by direct contact from host
to host. While mites can live off of a host for days to weeks depending on
their life stage, they are only infective for 36 hours, which means that
environmental decontamination is generally not necessary.
Mite infections on humans are self-limiting (i.e., they go away on their
own) as the mite is not able to complete its life cycle on the wrong host.
The condition is extremely itchy, though, while it lasts. The mites are
most active where skin is warm (in bed and where clothing is snug).
IF A SARCOPTIC MANGE ANIMAL IS IN THE HOME, IT
IS A GOOD IDEA TO WASH ANY BEDDING IN THE WASHING MACHINE (OR REPLACE WITH
NEW BEDDING), AND WASH ANY COLLARS OR HARNESSES.
Copyright 2006 - 2007 by the Veterinary
Information Network, Inc. All rights reserved.
This work was originally published by Veterinary Information
Network, Inc. (VIN) and is republished with VIN's permission.
**************************
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Demodectic Mange
(Sometimes called Red Mange) Demodectic mite
The Culprit - Demodex Canis
Demodectic mange is caused by a microscopic mite called Demodex canis.
All dogs raised normally by
their mothers possess this mite as mites are transferred from mother
to pup via cuddling during the first few days of life. (After the pup is
older it is unable to pick up demodex mites. Puppies raised by hand do not
ever get demodex mites.) For some reason, conditions change in certain dogs
to allow demodex mites to gain the upper hand; the mites proliferate and
can cause serious skin disease.
Mites are not transmitted to people or other dogs except from mother
dog to pup as described. Demodectic mange (unlike sarcoptic mange) is not
contagious.
Mites live inside hair follicles -- a difficult place for miticides (chemicals
that kill mites) to reach.
Mites are a normal residents of dog skin; it is only in some individual
dogs that mites cause problems.
Demodicosis -- The Disease Itself
Demodectic mange, also called demodicosis, has three forms:
Form #1: Localized
Usually a red, scaly, well-circumscribed lesion on the face or forelegs
is present. It generally goes away on
its own. Goodwinol ointment, an insecticide, may be used daily to control
localized demodicosis. Hair regrowth should be evident after about a month
of treatment; however, some localized cases appear "destined" to become
generalized and no treatment will prevent this from occurring.
When ointment is used, rubbing the medication on the area may break off
the weaker hairs at the margin of the lesion. The lesion may thus appear
to get larger at first. Antibacterial gels are also used against localized
demodicosis and associated skin infections. Often it is best not to treat
this condition and to simply allow it to resolve on its own.
Enlarged lymph nodes are a bad sign -- often foretelling generalized
mange.
Can the Pup Be Bred Later?
Sometimes the puppy with localized demodicosis was obtained for breeding
purposes. The current recommendation is not to treat these puppies so that
we can determine if the condition will stay localized and resolve or if
it will generalize. If it stays localized and eventually resolves without
treatment, the animal is still a candidate for breeding. If the condition
generalizes to cover the entire body, the animal should be sterilized. If
the condition receives treatment and resolves, we will never know how the
disease would have gone in its natural state and will not know whether the
pup is carrying the genetic predisposition for demodectic mange. In this
case, it is best to be conservative and not take the chance of passing on
genetic predisposition for this disease.
Localized demodicosis is almost exclusively a "puppyhood" disease. When
a puppy develops localized demodicosis the chance of the condition resolving
are 90% unless there is a family history of demodicosis in related dogs.
In this case, chance of spontaneous resolution drops to 50%.
Occasionally an adult dog develops localized demodicosis. We currently
do not have good understanding of the prognosis or significance of this
condition in an adult dog.
Form #2: Generalized
The entire dog is affected with patchy fur, skin infections, bald, scaly
skin.
Most generalized demodicosis starts as localized demodicosis.
Adult Onset-- Most demodicosis occurs in young dogs. An older dog should
not get demodicosis unless it has an underlying problem with its immune
system, possibly even cancer. A veterinarian should be consulted regarding
possible primary diseases.
Juvenile Onset -- 30% to 50% of dogs under age 1 year recover spontaneously
from generalized demodicosis without any form of treatment. Usually treatment
is recommended, though, to facilitate recovery.
It is very important that dogs with a history of generalized demodectic
mange not be bred as there is a hereditary component to the development of
the disease.
Form #3: Demodectic Pododermatitis
This condition represents demodectic mange confined to the paws. Bacterial
infectious usually accompany
this condition. Often as generalized demodicosis is treated, the foot
is the last stronghold of the mite. Old English Sheepdogs and Shar-peis
tend to get severe forms of this condition. The infection can be so deep
that biopsy is needed to find the mites and make the diagnosis.
Stress and Generalized Demodectic Mange
Physiological stress is an important factor determining the degree of
severity of demodectic mange.
Females should be spayed as soon as the disease is controlled. Coming
into heat, hormone fluxes, and pregnancy are very stressful. Also, predisposition
to demodicosis is hereditary and should not be passed on.
The dog should be fed a reputable brand of dog food so as to avoid any
nutritionally related problems.
Keep the pet parasite-free. Worms are irritants that the pet need not
deal with and fleas may exacerbate the itchiness and skin infection.
Keep up the pet's vaccinations.
The mites themselves cause suppression of the immune system so the pet
needs every advantage to stay healthy.
Skin infections are usually present in these cases and antibiotics will
likely be necessary. It is very important that cortisone type medications
such as prednisone NOT be used in these cases as they will tip the immune
balance in favor of the mite.
Prognosis
The younger the dog, the better the chance of cure. In many cases of
adult-onset demodicosis, the disease is controlled by dips and baths but
cure is not always possible. Some cases can never be controlled.
Current Treatment of Choice -- Ivermectin
Ivermectinis a broad spectrum anti-parasite medication generally used
for food animals and horses. In dogs and cats it is licensed for use
as a heartworm preventive aand as a topical ear mite therapy; the use of
this medication to treat demodicosis is not approved by the FDA. When ivermectin
was a new drug, it was hoped that it could be used against demodectic mange
mites as at that time only labor intensive dipping was available for treatment.
Once it was discovered that daily doses are needed (most other parasites
can be controlled with wormings spaced several weeks apart) ivermectin
was found to be highly effective, quickly becoming the treatment of choice.
Ivermectin is inexpensive relative to Milbemycin (see below) and involves
no labor intensive bathing. It DOES, however, taste terrible if given orally
(it may be necessary for the owner to learn how to give ivermectin as an
injectable treatment.)
THIS MEDICATION IS NOT SAFE FOR USE IN COLLIES,
SHETLAND SHEEPDOGS, USTRALIAN SHEPHERDS, OLD ENGLISH SHEEPDOGS, AND SOME
WOULD SAY, ANY HERDING BREED.
There is an unfortunate tendency for people hoping to save money to get
their hands on large animal formulations of ivermectin and attempt to home
treat this condition. The chief reason why this is a bad idea is "ivermectin
sensitivity," a phenomenon famous in the collie breeds. It is important
to realize that sensitivity to ivermectin may not be predictably limited
to “collie breeds” and thus it is often prudent to use a lower test dose
before initiating the relatively high doses of ivermectin needed to treat
demodicosis. Recently a DNA test has been developed by Washington State University
which can determine whether or not an individual has ivermectin sensitivity.
(The test uses a cheek swab - for details visit www.vetmed.wsu.edu/vcpl). Not
all individuals of collie heritage are sensitive to ivermectin.
Another important reason not to attempt home treatment of this condition
with ivermectin is that there is a range of ivermectin doses used in the
treatment of demodicosis and it seems that higher doses do clear infection
faster than lower doses. This means that if a lower dose has been ineffective,
a higher dose may still work. This does not mean that a pet owner should
experiment with ivermectin doses on their own as there is some potential
for lethal toxicity if this drug is not used appropriately. It does mean,
though, that the affected dog needs to be appropriately rechecked at the
proper intervals so that the mite numbers can be checked and it can be determined
if the dose should be increased.
A related medication called doramectin can be used to treat demodicosis.
It is given as a weekly injection as opposed to daily treatment with ivermectin.
The same collie sensitivity exists with doramectin and there is no
price advantage so the only benefit over ivermectin, if there is one, relates
to the weekly administration schedule.
Traditional Treatment -- Amitraz (Mitaban) Dips
Unless the animal is largely bald or has a short coat, complete clipping
will be required for maximal contact with the dip.
Dip should be preceded by a benzoyl peroxide bath (oxydex or pyoben shampoo).
This helps clear up skin infections and also helps open the hair follicles
so the dip can penetrate to the mites. Shampoo must sit on the pet at least
10 minutes before rinsing. Caution: This type of shampoo can stain jewelry
and clothing.
Dip is applied by sponge. Gloves should be worn while applying dip. The
dip dries on the dog's fur and should not be rinsed off. The dog should not
get wet between dips.
Dipping occasionally yields mild sedation as a side effect. Very small
dogs may become highly sedated and require an antidote but this is unusual.
For your convenience, dipping and bathing may be performed at the hospital
thus allowing for veterinary supervision in the event of side effects.
Dipping/bathing is recommended every 2 weeks on the bottle of dip. Most
universities are finding that the cure rate jumps from 25% to 80% when dip
is used at double strength and applied weekly. No toxic effects have been
seen using the dip in this way and this is our current recommendation except
in very small dogs and puppies.
The pet's skin is scraped every 2 weeks until 2 consecutive scrapings
are negative. Dipping/bathing is discontinued and the pet is rechecked in
one month. Dipping/bathing are reinstituted if mites are again found.
Amitraz dipping should not be used in toy breeds
or in very young puppies.
NOTE: Amitraz is a drug of the monoamine oxidase inhibitor class.
People who are taking selected serotonin reuptake inhibitors (such as Prozac®)
could have a bad reaction to the use of amitraz if they administer dips
to pets.
NOTE: Recently Upjohn Pharmacia merged with Pfizer Animal Health.
Prior to this, Mitaban dip was on an "indefinite" backorder. Pfizer
Animal Health plans to reintroduce Mitaban dip as soon as possible and
does not consider this product to have been discontinued. Large animal
formulations of Amitraz are available but their use in small animals is
considered to be off-label. If you are interested in Amitraz therapy
for demodicosis, consult your veterinarian.
Something Else Your Veterinarian Might Try -- Interceptor®
Interceptor (active ingredient: Milbemycin oxime) is normally marketed
as a monthly heartworm preventive; when it is used on a daily basis, it
is effective against generalized demodicosis. This discovery was welcomed
by the veterinary profession as finally demodicosis could be treated without
labor-intensive dipping. The downside to this treatment is expense, plus
an owner can expect to be using this medication daily for up to 3 months
to achieve cure.
Interceptor may be used in any patient safely; the only downside is expense.
Relapse?
Relapse is always a possibility with generalized demodicosis but most
dogs that relapse do so within a 6 to 12 month period from the time they
appear to have achieved cure. When relapse occurs it is often because the
dog appeared to be normal and the owner did not return for the appropriate
rescrapings. The final scrape is performed one month after treatment has
stopped.
Sarcoptic mange is a completely different disease.
We Wish it Wasn't Necessary to Add This
Some 30 years ago, dipping
dogs with demodectic mange in motor oil was a popular home remedy. Skin
exposure to motor oil can cause rashes and skin destruction in severe cases.
The hydrocarbons can be absorbed through the skin and cause a dangerous
drop in blood pressure. If motor oil is licked off the coat, resultant
vomiting can lead to aspiration of motor oil into the lungs and pneumonia.
Kidney and liver damage can result from motor oil dipping.
Please: Do not dip your dog in motor oil!
Copyright 2006 - 2007 by the Veterinary
Information Network, Inc. All rights reserved.
This work was originally published by Veterinary Information
Network, Inc. (VIN) and is republished with VIN's permission.
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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
|
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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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.
What is Ivermectin?
