Exotis ISSN 2398-2985

Reptiles

Ecdysis / dysecdysis

Synonym(s): Shedding / poor shedding

Contributor(s): Robert Johnson, Nathalie Wissink-Argilaga, Livia Benato

Introduction

  • Definition:
    • Ecdysis: the process of shedding the dead outer skin in reptiles.
    • Dysecdysis: abnormal shedding of the dead outer skin in reptiles.
  • Cause: dehydration, skin infection, skin wounds, burns, scars, ectoparasitism, poor or unbalanced diet, suboptimal husbandry, suboptimal environmental temperatures, stress, metabolic issues.
  • Signs: snakes shedding skin in pieces, retained sheds in lizards/chelonia (especially around toes and tail in lizards). Terrapins not shedding their scutes properly.
  • Diagnosis: physical examination.
  • Treatment: improve husbandry and diet, rehydration, treat underlying disease/skin infection, ectoparasite treatment and control.
  • Prognosis: fair to good.
Dysecdysis is not a primary disease; the underlying cause should be investigated and addressed.

Ecdysis and the pathogenesis of dysecdysis

  • Reptile skin is unique, differing from mammals in thickness, elasticity and strength Chelonia anatomy and physiology Lizard anatomy and physiology Snake anatomy and physiology.
  • Snake and lizard skin consists of a series of elevated scales continuous with each other at a hinge region.
  • Each body scale has an outer surface, and an inner surface which overlaps the adjacent scale.
  • Only the epidermal components of the scale participate in the shedding process.
  • The shedding mechanism, ecdysis is a normal characteristic of most reptiles, is usually periodic and complete in snakes and some lizards but often only partial in other species.
  • Ecdysis is dependent upon the health of the snake, the ambient temperature, humidity and other environmental factors.
  • In all snakes, the whole epidermis is shed, including spectacles.
  • The epidermal splitting occurs after the infiltration of lymph and enzymes between the old and the new skin.
  • Younger animals shed the skin more frequently than older animals.
  • Healthy adult pythons undergo ecdysis approximately every 2-3 months; in younger snakes it occurs more often.
  • Dysecdysis occurs commonly when environmental conditions are not ideal, eg suboptimal temperature, humidity and enclosure hygiene, stress, etc.
  • Hyperthyroidism may cause an increased frequency of ecdysis in some snakes (every 10-14 days).
  • Other underlying disease can also manifest with dysecdysis.
Print off the Owner Factsheets on Skin conditions in chameleonsSkin conditions in geckos, Skin conditions in lizards, Skin conditions in snakes, Skin conditions in terrapins and/or Skin conditions in tortoises to give to your clients.

Pathogenesis

Etiology

  • Dehydration.
  • Ectoparasites (Ophionyssus natricis).

Predisposing factors

General

Specific

  • Dehydration.
  • Temperatures.
  • Poor diet.
  • Anorexia.
  • Skin infection/wounds.
  • Scars.
  • Ectoparasites.
  • Stress.

Pathophysiology

  • Major differences in physiology and cutaneous biology between mammals and reptiles
  • Epithelium is thin, consisting of one or two layers of cells covered by two zones of keratin.
  • Dermal-epidermal junction is smooth.
  • Dermis is thinner and less vascular than mammalian skin.
  • Fewer glandular structures.
  • Dermis is attached to the underlying musculature by a small amount of loose connective tissue.
  • Range of stiffness or elasticity in snake skin is great compared with other vertebrate groups.
  • Diversity in the structure and function of dermal collagen fibers.
  • Epidermal growth and replacement of the old layer with the new is continuous in chelonians and crocodilians or discontinuous in lizards and snakes.
  • Shedding cycle in lizards and snakes has a resting stage, followed by 5 stages of renewal.
  • As a snake enters the renewal stages the skin becomes more dull and blueish in color due to the presence of lipid between the two layers:
    • The scales are rougher to touch.
    • The spectacle becomes milky in appearance.
  • Ecdysis is controlled by the pituitary/thyroid axis.

Timecourse

  • Ecdysis: frequency varies, depending upon on metabolic rate, environment, external factors.

Epidemiology

  • Dysecdysis: multiple animals may be affected if dry environment, poor hygiene, lower temperatures, ectoparasites are mitigating factors.

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.
  • Maderson P F A (1965) Histological changes in the epidermis of snakes during the sloughing cycle. J Zool 146 (1), 98-113 WileyOnline.

Other sources of information

  • Jacobson E R (2007) Reptile Immunology. In: Infectious Diseases and Pathology of Reptiles. Ed: Jacobson E R. CRC Press, USA. pp 131-166.
  • Cooper J E (2006) Dermatology. In: Reptile Medicine and Surgery. Ed: Mader D R. Elsevier, USA. pp 196-216.
  • Fitzgerald K T & Vera R (2006) Dysecdysis. In: Reptile Medicine and Surgery. 2nd edn. Ed: Mader D. Saunders Elsevier, USA. pp 778-785.
  • Jacobson E R (1991) Diseases of the Integumentary System of Reptiles. In: Dermatology for the Small Animal Practitioner. Eds: Ackerman L & Nesbitt G. Veterinary Learning Systems Company, USA.


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