Chapter 11 - Keratinisation

Question 1

What is the normal epidermal cell renewal time in horses?

Answer 1

17 days

Question 2

Define xerosis

Answer 2

Dry skin (water content of the stratum corneum should be more than 10% to look and feel normal, optimum is 20-35%)

Question 3

How is benzoyl peroxide keratolytic?

Answer 3

It is metabolised in the skin to benzoic acid, which lyses the intercellular substance in the horny layer to account for its keratolytic effect.

Question 4

What is the difference between an emollient and a moisturiser?

Answer 4

Emollients are agents that soften or soothe the skin, whereas moisturisers increase the water content of the stratum corneum.

Question 5

What is the most common form of primary seborrhea in the horse and is it pruritic?

Answer 5

Mane and tail seborrhea - not pruritic

Question 6

Does linear keratosis follow:

• blood vessels
• lymphatics
• nerves
• dermatomes
• none of the above

Answer 6

None

Question 7

Name a breed reportedly affected by liner keratosis?

Answer 7

Quarter horses
Thoroughbred
Standardbred

Question 8

Is linear keratosis typically orientated vertically or horizontally?

Answer 8

Vertically

Question 9

What do the lesions of linear keratosis look like?

Answer 9

0.25-0.35cm width and 5-70cm length bands of multiple hyperkeratotic papules that coalesce into bands - not pruritic nor painful

Question 10

Is the compact hyperkeratosis in linear keratosis ortho- or para-keratotic?

Answer 10

Orthokeratotic

Question 11

What are the clinical signs of cannon keratosis?

Answer 11

Moderately well-circumscribed plaques of scaling, crusting, hyperkeratosis, and alopecia are initially seen bilaterally over the cranial surface of the rear cannon bone areas