DERMATOMYOSITIS
Dermatomyositis can be a devastating disease for a Sheltie
or any dog if it affects the internal organs.
Information on dermatomyositis is available to
veterinarians and the lay public in a variety of veterinary publications. The
newest and most widely available is in Muller and Kirk's: Small Animal
Dermatology - 5th ed.
Philadelphia
: W.B. Saunders, 1995, pages 759-764. If the information below is published,
please put that reference as the source so your readers and their veterinarians
will know where to go to get more complete details. There is also some
more information here at the Dogpatch, courtesy of Kim Schive. I also found
a homepage for a sheltie
with dermatomyositis.
- Recognized in many
different breeds but especially common in Collies and Shelties.
- Both the skin and
muscle can be involved. It is very unusual to have muscle signs without skin
disease. In most cases, only dogs with moderate to severe skin lesions have
clinically significant muscle disease. The skin disease may or may not be
active when the muscle disease is recognized.
- Although there appears
to be a rare adult-onset variant, most affected dogs develop skin lesions
early in life. Typically, skin lesions are first seen in dogs 12 to 24 weeks
of age. The lesions may be short-lived or persist and worsen over the next
several months.
- Skin lesions occur in
areas of trauma. The gums, tips of the pinnae [ears], skin on the bridge of
the nose and face, skin over the joints and toes of the limbs, and tip of
the tail are common sites of involvement.
- Skin lesions can heal
rapidly without treatment or persist and worsen with time. In dogs which
don't heal rapidly, it can take months before the extent of the skin lesions
is known.
- Skin lesions are
variable in size and are hairless, red, and scaly or crusty. In most dogs,
the lesions are not itchy. The skin lesions seen in dermatomyositis are not
unique to this disease. Dogs with ringworm, bacterial skin infection,
demodectic mange, and discoid lupus, to name a few, can have similar
lesions. No one can make the diagnosis of dermatomyositis or exclude that
diagnosis simply by looking at the dog. Diagnostic tests must be performed.
Skin biopsies are very important especially if the dog or any of its
relatives are to be used for breeding.
- Since the diseases has
a genetic component, there is no cure for the disease. There are a variety
of treatments which can help the dog. No treatment plan is best for all dogs
and treatments must be individualized for each dog. Severely affected dogs
are very problematic.
- The genetic basis for
the disease is unknown in the Sheltie. An autosomal dominant trait has been
suggested but not proven by detailed breeding studies. These breeding
studies must be done to develop that data.
- ALL AFFECTED DOGS,
REGARDLESS OF THE SEVERITY OF THEIR SKIN LESIONS, SHOULD NOT BE USED FOR
BREEDING. Until the mode of inheritance is known, specific recommendations
about breeding relatives of an affected dog can not be made.
Note
especially points 8 and 9. Affected dogs: don't breed. Relatives of affected
dogs: recommendations not possible without further research. Be cautious but not
hysterical. Note also that there is no mention of DM being an autoimmune
disease, very likely it is one of the "unknowns" about the disease.
Here are some links to DM, DM research and donations to DM
research
http://www.assa.org/vet.html
http://www.shalaine.com/dm/dm.html
http://www.dogpatch.org/sheltie/morederm.html
http://www3.igalaxy.net/~grashopr/buddy.htm
