Canis ISSN: 2398-2942

Skin: pigmentary disorders

Contributor(s): David Scarff, Charlie Walker

Introduction

  • Common presentation of a variety of dermatological problems.
  • Cause: usually secondary to chronic dermatological disease.
  • Primary pigmentary abnormalities rare.
  • Usually of cosmetic concern only.
  • Signs: may be associated with systemic disease.
  • Diagnosis: most important reason for pursuing the underlying cause of changes in pigmentation is to determine if it is a manifestation of systemic disease.

Pathogenesis

Etiology


Hyperpigmentation - genetic Hyperpigmentation - acquired Hypopigmentation - genetic
  • Piebaldism.
  • Non-inflammatory nasal depigmentation Nasal depigmentation.
  • Mucocutaneous hypopigmentation.
  • Vitiligo Skin: vitiligo 01 Skin: vitiligo 02.
  • Albinism.
  • Waardenburg-Klein syndrome.
  • Canine cyclic hematopoiesis Cyclic hematopoiesis.
  • Tyrosinase deficiency.
Hypopigmentation - acquired Pigment changes/atypical pigmentation - genetic Pigment changes/atypical pigmentation - acquired
  • Red hair from saliva or tear staining.
  • Cutaneous flushing.
Nasal depigmentation

Pathophysiology

  • May be hereditary or acquired.
  • May involve increased or decreased skin pigmentation.
  • Unclear.
  • Melanocytes produce melanin and are found in highest numbers in epidermis, mucus membrane epithelium and hair follicle epithelium.
  • Melanin is incorporated into keratinocytes by pinocytosis.
  • Clinical pigmentation is due to the amount and organisation of melanin-containing melanosomes in the keratinocytes.
  • Control mechanisms include genetic factors and poorly understood local factors, eg ultraviolet light, inflammation, hormones.

Diagnosis

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Further Reading

Publications

Refereed papers

Other sources of information

  • Alhaidari Z and Gaugere E (2008)Diagnostic approach to depigmentation of the nasal planum.In: Gaugere E & Prelaud P (eds)A Practical Guide to Canine Dermatology.Kalianxis, pp 543-549. ISBN 978291578115.
  • Alhaidari Z (2001)An approach to disorders of pigmentation.In: Foster A and Foil C (eds)Manual of Small Animal Dermatology. 2nd edn. British Small Animal Veterinary Association, pp 66-70. ISBN 0905214587.
  • Muller G Het al(eds) (2001)Muller and Kirk's Small Animal Dermatology.6th edn. Philadelphia: W B Saunders, pp 1005-1024. (Detailed dermatology textbook for in-depth reading). ISBN 0721676189.
  • Morielo K A (1995)Pigmentary disorders.In: Morielo, K A and Mason, I S (eds)Handbook of Small Animal Dermatology.Pergamon Press, pp 119-126. (Excellent problem-oriented approaches and diagnostic plans.)
  • MacDonald J M (1993)Hyperpigmentation and nasal depigmentation.In: Griffin, C E, Kwochka, K W and MacDonald, J M (eds)Current Veterinary Dermatology - the Science and Art of Therapy.St Louis: Mosby Year Book, pp 223-241. (Well presented dermatology text book.)


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