Small Animal Dermatology - Chapter 4

 
 
   
 
 

Small Animal Dermatology is part of the 'Saunders solutions in veterinery practice' series published by Elsevier.

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Chapter 4 - Sarcoptic Mange

 

Chapter 4 - Sarcoptic mange

INITIAL PRESENTATION
Pruritus with erythema, alopecia, papules, crusting and scaling.

INTRODUCTION
Sarcoptic mange (also referred to as scabies) is a highly contagious, intensely pruritic and potentially zoonotic skin condition, due to an infestation of the skin by a sarcoptid mite Sarcoptes scabiei var. canis. The presenting signs of pruritus ­ papules, crusting, scaling, erythema and self-induced alopecia ­ are often confused with other dermatological conditions, such as staphylococcal pyoderma, allergic skin diseases or other ectoparasitic diseases.

CASE PRESENTING SIGNS
A 13-year-old uncastrated male samoyed was presented with severe pruritus, to the extent that the dog was continually scratching in the waiting room and during the consultation. It was also lethargic and exhibited erythema, alopecia, crusting and scaling.

 

CASE HISTORY
All dogs present with a history of intense pruritus, which in most cases fail to respond to increasing doses of glucocorticoids. The onset of pruritus tends to be sudden and severe, and the animal is usually presented shortly after onset, unless the individual has been intermittently treated with ectoparasiticidal products. A history of indirect contact with foxes is usually noted, especially in urban and suburban areas of the UK. Sarcoptic mange is contagious and of zoonotic importance, and evidence of contagion and zoonosis may come to light during the history taking.

The history in this case was as follows:

  • The dog was acquired from a rescue centre 3 years prior to presentation.

  • The dog had no previous history of skin disease, apart from having several sebaceous cysts removed surgically a few months before.

  • The pruritus started about 2 months prior to presentation and had worsened over this period.

  • The dog's environment and management had not altered over this period.

  • There were no in-contact dogs, but there were foxes in the garden.

  • The owner reported that the dog was lethargic and depressed.
  • There was no zoonosis.

  • The pruritus initially responded to oral prednisolone but, as the disease progressed, even increasing doses had no effect.

  • Systemic antimicrobial therapy, for 7 days, was of no benefit.

  • Flea control was sporadic.
 

CLINICAL EXAMINATION
The clinical signs can range from subtle lesions with marked pruritus to severe lesions. The primary lesions include erythematous and/or crusted papules, and secondary lesions include crusts, lichenifi cation, scaling and hyperpigmentation. Initial lesion distribution tends to be on the ear margins, elbows, sternum and the hocks. If untreated the lesions can become widespread and often affect the demeanour of the dog, as in this case.

The physical and dermatological examination revealed:

  • The temperature, heart rate and respiratory rates were within normal limits.

  • Generalized skin lesions affecting the trunk, caudal aspects of the thighs, dorsal aspect of the tail and the feet (Figs 4.1 and 4.2).

Chapter 4 - continued

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