Skin: ichthyosis
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.
Presenting signs
- Focal or general hyperkeratosis of skin and footpads.
- Excessive cutaneous scaling and/or adherent plaques.
- Scales may be darkly pigmented.
- Affected Cavalier King Charles Spaniels may also have frizzy coats, deformed claws and concurrent keratoconjunctivitis sicca Keratoconjunctivitis sicca Curly coat dry eye syndrome.
Age predisposition
- Affected animals show signs at birth although may not be recognized as a clinical problem until later in life.
Breed/Species predisposition
- American Bulldog Bulldog.
- American Staffordshire Terrier American Staffordshire Terrier.
- Australian Terrier Australian Terrier.
- Boston Terrier Boston Terrier.
- Bull Terrier Bull Terrier.
- Cavalier King Charles Spaniel Cavalier King Charles Spaniel.
- Collie Collie - Rough.
- Cross-breds.
- Dobermann Dobermann.
- English Springer Spaniel English Springer Spaniel.
- Golden Retriever Retriever: Golden.
- Great Dane Great Dane.
- Irish Setter Irish Setter.
- Jack Russell Terrier/Parson Terrier Parson's Jack Russell Terrier.
- Labrador Retriever Retriever: Labrador.
- Manchester Terrier Manchester Terrier.
- Norfolk Terrier Norfolk Terrier.
- Pit Bull Terrier.
- Rottweiler Rottweiler.
- Soft-coated Wheaten Terrier Soft Coated Wheaten Terrier.
- West Highland White Terrier West Highland White Terrier.
- Yorkshire Terrier Yorkshire Terrier.
Cost considerations
- Oral isotretinoin has been used successfully but is expensive and difficult to obtain.
- Long-term daily use of shampoos and emollients needed.
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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Prevention
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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.