Canis ISSN: 2398-2942

Skin: familial dermatomyositis

Contributor(s): David Scarff, Susan E Shaw, David Godfrey

Introduction

  • Uncommon familial immune-mediated disease of skin and muscle.
  • Cause: may vary, there are inherited immune-mediated factors in the commonly affected breed but environmental factors such as infections and stress occur.
  • Signs: skin disease - papules, pustules, crusting, erosion, ulceration. Often also muscle wastage and dysfunction.
  • Seen in Rough Collie and Shetland Sheepdog (also other breeds less commonly).
  • Diagnosis: history, clinical signs, histopathology.
  • Treatment: none, apply sunblock, immunosuppressive therapy.
  • Prognosis: depends on severity, cautious - guarded.

Pathogenesis

Etiology

  • A genetic immune-mediated defect is suspected in the breeds most commonly affected and some abnormal loci have been reported in Shetland Sheepdogs and Rough Collies.
  • This follows breeding studies that suggest a dominant trait with incomplete penetration.
  • Environmental factors are probably also involved - stress, infections, vaccinations.

Pathophysiology

  • Hereditary, possibly autosomal dominant pattern.
  • Believed to be immune-mediated inherited defects, possibly secondary to infectious agents.

Timecourse

  • Skin lesions start to appear by six months of age and their full extent is reached by 1 year. They may subsequently improve.
  • Muscle disease lags behind skin lesions and its severity usually mirror the severity of the dermatopathy (muscle disease is less common in Shetland Sheepdogs).

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

  •  Recent references from PubMed and VetMedResource.
  • Evans J M, Noorai R E, Tsai K L, Starr-Moss A N, Hill C M, Anderson K J et al (2017) Beyond the MHC: A canine model of dermatomyositis shows a complex pattern of genetic risk involving novel loci. PLoS Genet 13 (2), e1006604 PubMed.
  • Wahl J, Clark L, Skalli O et al (2008) Analysis of gene transcript profiling and immunobiology in Shetland sheepdogs with dermatomyositisVet Dermatol 19 (2), 52-58 PubMed.
  • White S D, Shelton G D, Sisson A et al (1992) Dermatomyositis in an adult Pembroke Welsh Corgi. JAAHA 28 (5), 398-401 VetMedResource.

Other sources of information

  • Miller W H, Griffin C E & Campbell KL (2013) Familial canine dermatomyositis. In: Muller & Kirk's Small Animal Dermatology. 7th edn. Elsevier, St Louis. pp 585-587. 
  • Yager J A & Wilcock B P (1994) Color Atlas and Text of Surgical Pathology of the Dog and Cat. London: Wolfe Publishing, Mosby Year Book Europe. ISBN 0 7234 1827 6.
  • Gross T L, Irkhe P J & Walder E J (1992) Veterinary Dermatopathology. St Louis: Mosby Year Book. ISBN 0 8016 5809 8.
  • For information on Genetic Testing Providers (labs) genetic tests, and tests by breed, visit International Partnership for Dogs (https://dogwellnet.com/).
  • For a list of DNA tests available for certain breeds worldwide, visit Kennel Club Worldwide DNA tests: https://www.thekennelclub.org.uk/health/for-breeders/dna-testing-simple-inherited-disorders/worldwide-dna-tests/.

Organisation(s)


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