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MANGE Mange
is a parasitic skin disease caused by microscopic mites. Two different mange
mites cause skin disease in dogs. One
(the demodectic mite) resides in the hair follicles, while the other (the
sarcoptic mite) lives just under the surface of the skin.
Although both mites share some similar characteristics, there are also
important differences. It is
important not to confuse the two types of mange because they have different
causes, treatments, and prognoses. DEMODECTIC
MANGE What
causes demodectic mange? Demodectic
mange, sometimes just called "demodex", is the most common form of
mange in dogs. It is caused by the
demodectic mange mite, a parasite which lives in the hair follicles of affected
dogs. Under the microscope, this
mite appears shaped like an alligator with 8 legs.
All dogs (and many humans) have a few of these mites on their skin.
As long as the body's immune system is functioning, these mites cause no
harm. Demodectic
mange most often occurs when a dog has an immature immune system, allowing the
mites to grow rapidly. Therefore,
this disease occurs primarily in dogs less than 12-18 months of age.
In most cases, as a dog matures, the immune system also matures.
Adult dogs which have the disease usually have defective immune systems. Does
this mean that demodectic mange is not contagious? Yes.
Since the mite is found on virtually all dogs, exposure of a normal dog
to one with demodectic mange is not dangerous. Why
doesn't the immune system mature correctly in some dogs? Development
of the immune system is under genetic control.
Thus, an affected dog usually comes from a litter containing other
affected puppies. Owners of litter
mates should be put on the alert to watch for it.
Because the disease is often due to a genetic defect, affected dogs
should not be bred. Also, parents
of the affected dog should not be bred again. Sometimes
the disease can occur as a result of treatment of the dog with immunosuppressant
drugs including corticosteroids. What
does demodectic mange do to the dog? Surprisingly,
a dog with demodectic mange does not itch severely, even though it loses hair in
patches. Areas of bare skin will be
seen. The hair loss usually begins
on the face, especially around the eyes. When
there are only a few patches of hair loss, it is termed localised demodectic
mange. If the disease spreads to
many areas of the skin, it becomes generalised demodectic mange.
How
is demodectic mange treated? The
localised form is usually treated with topical medication.
The generalised form requires special shampoo and dips and sometimes
medication either by injection or by mouth.
Shampooing with special cleansing shampoos helps to flush out the hair
follicles prior to dipping or rinsing techniques.
Dipping is described below. For
dogs with generalised demodectic mange, secondary skin infections may represent
a complicating factor requiring antibiotic therapy.
Dogs with skin infections have very red, inflamed skin.
This is the source of the term "red mange".
What
is the prognosis for my dog? Treatment
of the localised form is generally successful.
Treatment of the generalised form is also usually successful.
However, if the immune system is defective, neither the mites nor the
infection may respond to treatment. Following
successful treatment, is it likely to recur? Because
the immune system does not mature until 12-18 months of age, a dog with
demodectic mange may have relapses until that age.
It is important for retreatment to begin promptly to minimise the
possibility of developing uncontrollable problems.
Demodectic mange may also occur in very old dogs because function of the
immune system often declines with age. Dogs
who have immune suppression due to illness or medication are also candidates for
demodectic mange. The
dip or shampoo commonly used for demodectic mange contains the insecticide
amitraz. The manufacturer's instructions must be carefully followed.
The product can have side effects both to your dog and yourself if not
properly used. If in doubt consult
your veterinary surgeon. After the
treatment it will be necessary to examine your dog for the presence of live
mites or mite eggs. Further
treatment will be determined by the results.
If you do the dipping yourself, be sure to wear rubber gloves to prevent
getting it on your hands. Sometimes
treatment will involve the use of products that are not licensed for specific
use in the dog. Your veterinary
surgeon will discuss these with you and the implications involved. It is
sometimes necessary to use these products since the risk surrounding their use
is less than the risk of untreated demodectic mange. Side
Effects Of Treatment Follow
the instructions carefully. If
your dog goes off food, is sick or unusually quiet, please contact us. Please
return as requested. This
is important. SARCOPTIC
MANGE What
causes sarcoptic mange? Sarcoptic
mange is caused by a mite that burrows just beneath the surface of the skin.
It may also crawl around on the skin surface. The mite feeds on material in and on the skin. What
does it do to the dog? The
presence of the sarcoptic mite causes severe itching.
The dog will chew and scratch its skin constantly.
This leads to the loss of large amounts of hair, especially on the legs
and belly. Eventually, the skin
will become thickened and will darken due to pigmentation. Is
it contagious? Sarcoptic
mange is highly contagious to other dogs; it is also contagious to humans, and
is known as scabies. The dog's
bedding should be discarded or if this is not possible, it should be regularly
washed in hot water with bleach or one of the specific anti-scabies shampoos.
Although the mites are not able to complete their life cycle on humans,
they will cause quite a bit of itching before they finally die. How
is sarcoptic mange diagnosed? Diagnosis
is made by a skin scraping that is examined under the microscope.
However if only a small
number of mites are present on the dog all skin scrapings may be
negative. A presumptive
diagnosis is then made because the signs are so suspicious and treatment is
commenced without the confirmation of a skin scraping.
Age is not a significant factor in sarcoptic mange.
Although most common in puppies, it affects dogs of all ages. How
is it treated? There
are several insecticides which are effective against this mite.
Various dips and shampoos are available. Bathing
should occur weekly for at least 4 weeks, at which time your dog should
be re-examined to determine if further treatment is needed.
Should bathing not prove effective injections with a preparation called
ivermectin may be successful but this product is not licensed for use in dogs.
Your veterinary surgeon will discuss the implications prior to its use. Instructions
We
have supplied shampoo and a rinse. Please
follow the instructions carefully. After
applying the rinse......................should be air dried in a towel or with a
hairdrier. Preferably
discard any bedding or alternatively wash in bleach and soak in the diluted
rinse. If
your dog is still scratching in 4-5 days please contact us.. Your
dog should be re-examined in ____ days. If
any member of the family develops an itching skin rash, please contact your
doctor immediately. Tell your doctor that you have been exposed to
sarcoptic mange (also known as scabies). In
people, the mite cannot complete its life cycle so it will die in a few days.
However, it may cause itching during that time.
Reinfestation from the dog or the premises can result in continued
itching. |