Canis ISSN: 2398-2942

Skin: ichthyosis

Contributor(s): Karen Campbell, David Scarff, Susan E Shaw

Introduction

  • Cause: rare congenital skin disease of dogs.
  • Signs: extreme hyperkeratosis on all or part of skin.
  • Footpads greatly thickened.
  • Excessive cutaneous scaling and/or adherent plaques.
  • Diagnosis: clinical signs, age of onset, histopathology, genetic testing.
  • Treatment: oral isotretinoin and long-term use of shampoos and emollients.
  • Prognosis: guarded - incurable and euthanasia may be requested.

Pathogenesis

Etiology

  • Multiple subtypes of ichthyosis are likely to be present.
  • Epidermolytic forms have been associated with a defect in keratin 10 formation.
  • Non-epidermolytic forms have been associated with deficiencies in transglutaminase 1.
  • Congenital ichthyosis in Golden Retrievers is associated with a PNPLA1 mutation.
  • Congenital keratoconjunctivitis sicca and ichthyosiform dermatitis in Cavalier King Charles Spaniels is associated with a mutation of the FAM83H gene.
  • Icythyosis in American Bulldogs is associated with NIPAL4 (ICHTHYIN) deficiency.
  • Icythyosis in Great Danes is associated with a novel SLC27A4 splice acceptor site mutation.
  • Other reported mutations include defects in 12R-lipoxygenase, eLOX-3, and the ABCA12 gene (resulting in deficiency in transporter proteins for epidermal lipids).

Predisposing factors

General
  • Hereditary, majority associated with mutations in autosomal recessive genes.

Pathophysiology

  • Congenital.
  • A range of pathophysiological defects may be present depending on breed affected.
  • One study in West Highland White Terrier suggested that epidermal hyperproliferation was present.
  • Norfolk Terriers have a mutation in gene controlling keratin 10 production.
  • Jack Russell Terriers/Parson Terriers have a deficiency of transglutaminase production.
  • Cavalier King Charles Spaniels have a mutation in the FAM83H gene that results in keratoconjunctivitis, deformed claw growth, a frizzy coat and excessive scaling.
  • Hyperproliferation of epidermis, with very short epidermal cell renewal time.
  • Faulty formation of keratin filaments.
  • Faulty formation of lipid lamellae and other intracellular lipids.
  • Alterations in desquamation of stratum corneum.

Timecourse

  • Present at birth, persists throughout life.

Epidemiology

  • Majority of conditions are inherited as autosomal recessive traits Inherited diseases: genetic tests :
    • Affect approximately 25% of offspring when both parents are carriers.
    • Affect 50% when affected dog bred to a carrier.
    • Affect 100% if both parents are affected.

Diagnosis

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Treatment

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Hoffman A et al (2015) Congenital ichthyosis in 14 Great Dane puppies with a new presentation. Vet Pathol 53 (3), 614-20 PubMed.
  • Mauldin E A et al (2015) Autosomal recessive congenital ichthyosis in American Bulldogs is associated with NIPAL4 (ICHTHYIN) deficiency. Vet Pathol 52 (4), 654-662 PubMed.
  • DiGiovanna J J et al (2013) Systemic retinoids in the management of ichthyosis and related skin types. Dermatol Ther 26 (1), 26-38 PubMed.
  • Grall A et al (2012) PNPLA1 mutations cause autosomal recessive congenital ichthyosis in golden retriever dogs and humans. Nat Genet 44 (2), 140-147 PubMed.

Other sources of information

  • Maudlin E A (2013)Canine ichthyosis and related disorders in cornification.Vet Clin North Am Small Anim Pract43, 89-97.
  • Miller W H, Griffin G E, Campbell K L (2013)Muller and Kirk's Small Animal Dermatology7th edn. St Louis, Elsevier, pp 630-646.
  • Campbell K L (2012)An approach to keratinization disorders.Chapter 6 In: Jackson H, Marsella RBSAVA Manual of Canine and Feline Dermatology. 3rd edn, Gloucester, UK. pp 46-52.
  • 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.
  • Scott Wet al(eds) (1995)Muller and Kirk's Small Animal Dermatology.5th edn. Philadelphia: W B Saunders. p 745.


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