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.

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.

Pathogenesis

Etiology

• Dehydration.
• Ectoparasites (Ophionyssus natricis).

Predisposing factors

General

• Poor husbandry Chelonia husbandry Lizard husbandry Snake husbandry.
• Poor nutrition Nutritional requirements.
• Chronic problems.

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

Treatment

Prevention

Outcomes