Demodicosis

Demodicosis

Also called:

What is demodicosis?

Demodicosis is a mite infestation. Small populations of the mite, Demodex canis,
inhabit the hair follicles of normal dogs – and generally do not cause problems. If
the mite population becomes very large, however, it can cause a severe skin
disease called “mange”. Affected dogs may suffer from hair loss, painful or itchy
skin, and bacterial skin infections.
Cats can also develop demodicosis. One form, caused by Demodex cati, usually
affects cats with an underlying disease. Another form, caused by Demodex
gatoi, usually results in excessive grooming and hair loss.
Which pets get demodicosis?

If most dogs harbor Demodex mites, why don’t they all develop mange? It
appears that a normally functioning immune system is crucial for keeping the
mite numbers low. So when we diagnose dogs with demodicosis, we always
have to consider any underlying conditions that might be affecting their immune
function.
Young dogs, less than 18 months old, sometimes develop demodicosis before
their immune system fully matures. Most show only small patches of hair loss,
commonly on the face or legs. This form, called “localized” demodicosis, often
resolves without treatment. Others develop a “generalized” form affecting many
areas of the skin. Because this form is heritable, it is important to always spay or
neuter affected dogs. It must be treated medically to ensure a cure. In a study of
over 3,719 cases of generalized demodicosis in young dogs presented in 2009,
Dr. Plant identified the most susceptible breeds and identified other risk factors.
Sometimes, demodicosis develops for the first time in adult dogs. These dogs
also require medical treatment for their condition to resolve, and we always
recommend a screen for underlying conditions that may be suppressing their
immune system.
How is demodicosis diagnosed?

Demodicosis can only be definitively diagnosed by a veterinarian, because many
skin conditions in dogs look so much alike that they cannot be differentiated
based on appearance. In most cases, we perform a simple in-office test called a
skin scraping. This quick test also allows us to monitor our therapy on
subsequent visits. The screen for underlying diseases may include blood tests, a
review of the dog’s medical history, and other procedures.
How is demodicosis treated?

We treat demodicosis using an integrated approach. First, we institute anti-
parasitic therapy to kill the mites. The mites can be killed either using a series of
medicated dips, spot-on products, or a course of oral medication – the therapy is
tailored to each patient with consideration given to many factors. Antibiotics and
medicated shampoos may also be prescribed. Second, we address any
concurrent diseases that are present. The course of treatment for the mites may
be lengthy, ranging from weeks to months, and adjustments to therapy are often
needed. Follow-up care from a veterinarian is crucial to achieving a cure and
preventing a relapse.
Is it safe for my family to be around a dog or cat with demodicosis?

Yes. The mite does not spread to humans or to other species of animals. The
canine forms of demodicosis are not transmittable (all dogs have small numbers
already, acquired in the first days of life), but D. gatoi appears to be contagious
between cats.
Instructions for pet owners for the treatment of demodicosis in dogs

Mitaban Dips

Mitaban dips (by prescription only) can be performed in a veterinary clinic,
grooming establishment, or in a well-ventilated area at home. The dip needs to
penetrate the hair follicles in order to work.
• Medium or long-haired dogs are clipped prior to dipping, to decrease the toxicity and increase the efficacy of the Mitaban .
The dog is bathed with the prescribed shampoo to “flush” the hair follicles, but
must be thoroughly dried before the dip is applied. One bottle (10.6 mL) of the
Mitaban dip is diluted in 2 gallons of water. The dip must be used the same day
because the toxicity of Mitaban increases once it is opened and diluted.
The dip is poured and sponged over the entire dog. Please be sure to wear
gloves. Do not rinse the dog, and allow him to air-dry.
If the feet are affected, allow the dog to stand in the dip for at least 15 minutes.
We may also prescribe a solution to use on “problem” areas in between dips:
0.5 mL of Mitaban diluted in 1 oz of propylene glycol solution or mineral oil can
be applied to the areas every 48 hours. Make a new batch of this solution every
time you open a bottle of Mitaban for dipping. Repeat the dip in 1 to 2 weeks, as
directed.
Mitaban is a potentially toxic medication. Side effects of Mitaban are fairly
common and we often see a mild to moderate degree of sedation for 24 to 48
hours after a dip. Small breed dogs are particularly susceptible. Some dogs also
become itchier. Please contact us or your veterinarian if your dog exhibits
marked depression or lethargy. Most importantly, take measures to minimize
your own exposure to the dip.
Oral Ivermectin or Milbemycin

Although Mitaban dips have been used the longest for the treatment of
demodicosis, many owners prefer the convenience of oral medications.
Oral ivermectin solution or oral milbemycin tablets are usually given once daily
for the treatment of mites. Although these medications are safe in most dogs,
they can cause incoordination, depression, or other untoward side-effects that
you may notice. Dilated pupils are sometimes the only sign that indicate possible
toxicity. Ivermectin can be extremely toxic to some breeds of dogs (such as
Collies), so never use this drug without the supervision of a veterinarian, or to
treat an animal for whom it was not prescribed. A laboratory test is available to
determine if your pet is susceptible to ivermectin toxicity. These are considered
“off-label” uses (not FDA approved for this purpose) of these drugs.
Spot-on Advantage Multi® or Promeris®

Two spot-on treatments have also shown some benefit in the treatment of canine
demodicosis. Promeris® is now an approved treatment in the United States, and
Advantage Multi® for Dogs is approved in some other countries. The
convenience of these treatments is appealing, but they may not be effective in
more severe cases. Promeris® has a very strong eucalyptus odor that many
people find offensive.
Lime Sulfur for Feline Demodicosis

Cats with demodicosis are usually treated with weekly lime sulfur dips. This
treatment is very safe, but smelly. It is not effective for the treatment of dogs with
demodicosis.
Progress Examinations

With either topical or oral therapy, it is crucial to continue treating longer than the
time it takes to kill the mites. Remember that the mites can persist long after the
skin looks normal, and stopping therapy prematurely often leads to a relapse of
the disease. It is very important for us to monitor the progress of the treatment
by performing skin scrapings, because mites may be present even when the skin
looks normal. We usually schedule rechecks every 2 to 4 weeks until two
negative skin scrapings are obtained.

Source: http://www.skinvetclinic.com/pdfs/demodicosis.pdf