Congenital Diseases

CHAPTER | 10 Congenital Diseases




Epidermolysis Bullosa







Familial Canine Dermatomyositis



Features


Familial canine dermatomyositis is an inherited inflammatory disorder of the skin and muscles in which a microvascular vasculopathy is thought to play a role. The cause is unclear, but a genetic predisposition followed by a trigger (e.g., infection, other environmental factor) that initiates an immune-mediated process and the clinical signs has been proposed. It is uncommon in dogs, with the highest incidence in collies, Shetland Sheep dogs, and their cross-breeds. Lesions usually first appear in puppies at between 2 and 6 months of age. Several littermates may be affected, but the severity of the disease often varies significantly among puppies.


Skin lesions are nonpruritic, vary in severity, and may wax and wane. They are characterized by variable degrees of erythema, alopecia, scaling, crusting, erosion, ulceration, and scarring and, rarely, by papules and vesicles. Skin lesions occur on the bridge of the nose, around the eyes and lips, in the inner ear pinnae, on the tail tip, and over bony prominences of the distal extremities. Rarely, footpad ulcers are seen. Signs of muscle involvement are variable. Dogs may appear to be unaffected, to have bilaterally symmetrical atrophy of the masseter or temporalis muscle, or to have generalized symmetrical muscle atrophy. Dogs with masseter muscle involvement may have difficulty eating, drinking, and swallowing. Severely affected dogs may be weak, lethargic, stunted, lame, and infertile. If the leg muscles atrophy, affected dogs may exhibit an abnormal “high-stepping” gait. When the esophageal muscles are affected, megaesophagus may develop.





Treatment and Prognosis













image

FIGURE 10-5 Familial Canine Dermatomyositis.


The same dog as in Figure 10-4. Active lesions have resolved, leaving alopecic, scarred skin.


(Courtesy M. Mahaffey.)







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Sep 10, 2016 | Posted by in SMALL ANIMAL | Comments Off on Congenital Diseases

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