Crusting and scaling

Question 1

Define scale

Answer 1

an accumulation of loose cornified fragments of the stratum corneum

Question 2

Define crust. Cause?

Answer 2

presence of a dried exudate on the skin surface. Due to epidermal inflammation: severe oedematous response OR marked cellular recruitment.
3 common triggers: physical damage, infection, infestation

Question 3

Define seborrhoea

Answer 3

= flow of sebum. Vague clinical term for scaling/greasy exudation

Question 4

Define seborrhoea sicca

Answer 4

dry scaling

Question 5

Define seborrhoea oleosa

Answer 5

oily scaling

Question 6

Define seborrhoea dermatitis

Answer 6

greasy, inflammed skin

Question 7

What are the 2 main causes of scaling and crusting

Answer 7

Defects of keratinisation/cornificiation (use depends on vet). It refers to skin disease where scaling/follicular casting is a dominant clinical feature.
SECONDARY to: parasites, infection, nutritional, allergy, neoplasia.
PRIMARY: idiopathic, genetic defect

Question 8

What is spaniel seborrhoea?
Dx
Tx

Answer 8

• a primary defect in cocker spaniels
• increased mitotic rate/turnover time
• skin grafts remain hyperproliferative
• Dx - to exclude primary causes, biopsy
• Tx - shampoo, vitA, retinoids

Question 9

What is sebaceous adenitis?
Dx
Tx

Answer 9

• affects various breeds (St poodle, Akita)
• sebaceous glands destroyed
• Dx - exclude primary causes, biopsy
• Tx - shampoo, EFA, cyA, (retinoids)

Question 10

What are the problems with administering retinoids?

Answer 10

• teratogenic

- dry eye

Question 11

List Ddx for pruritic, steroid-resistant crusting lesions

Answer 11

• scabies
• (pemphigus)
• (dermatophytosis)
• (cutaneous lymphoma)

Question 12

What should you do if you suspect sarcoptic mange but don’t find it on the skin scrape?

Answer 12

Treat anyway (to avoid severe progression of disease if you didn’t detect it)

Question 13

How can scabies be treated? 4

Answer 13

• Amitraz (licensed of canine scabies) - weekly for 6 w
• body clip (to reduce amount of hair)
• Prednisolone (to reduce itch)
• Cephalexin (an AB to reduce secondary bacterial infection due to the excoriation
• Others: selamectin (stronghold/revolution), imidacloprid/ moxidectin (Advocate)

Question 14

Name 3 typical lesions of scabies

Answer 14

pruritus, papules and crusts

Question 15

T/F: scabies is often refractory to steroids

Answer 15

True

Question 16

T/F 3 weekly treatments may not be enough to treat scabies, especially in long coated breeds

Answer 16

True

Question 17

T/F: ivermectin is contraindicated in the treatment of scabies in collies

Answer 17

True

Question 18

Define dermatosis

Answer 18

a disease of the skin, especially one that does not cause inflammation.

Question 19

Define SND

Answer 19

Superficial Necrolytic Dermatitis

SYNONYMS = diabetic dermatosis, hepatocutaneous syndrome, metabolic epidermal necrosis, necrolytic migratory erythema.

Question 20

Describe SND lesions

Answer 20

Uncommon erosive, crusting, ulcerative disease which commonly affects the footpads, extremities and peiorificial skin of middle-aged and old dogs.

Question 21

When is SND seen?

Answer 21

with hepatic diseases (cirrhoisis, vacuolar degeneration) or pancreatic glucagonoma. Poor prognosis? reverse hepatic disease.

Question 22

List ddx for pruritic disease in heifers

Answer 22

• ectoparasite infestation
• dermatophytosis (ringworm in calves)
• dermatophilosis (mud fever, crusting lesion)
• nutritional abnormality
• inherited keratinisation defect

Question 23

Define parakeratosis

Answer 23

= a mode of keratinisation characterised by the retention of nuclei in the stratum corneum. In the MM this is normal. In skin, this leads to abnormal replacement of annular sqaumes with nucleated cells.

Question 24

Define orthokeratosis

Answer 24

the formation of an anuclear keratin layer, as in the normal epidermis

Question 25

Define hypotrichosis

Answer 25

a condition of abnormal hair patterns - predominantly loss or reduction of hair