Dermatological response to damage

Question 1

List ways in which the dermis can respond to damage

Answer 1

-Epidermal responses
Hyperkeratosis
Acanthosis
Lichenification
Vesicle formation
Crusting
-Dermal responses
Erythema
Oedema
Thickening
-Alopecia

Question 2

What is scaling?

Answer 2

• Type of hyperkeratosis
• Production of abnormal/ excessive scale
• Can be primary or secondary (more common)

Question 3

What keratinisation defect is common in golden retrievers?

Answer 3

Ichthyosis

Question 4

What is follicular hyperkeratosis?

Answer 4

• Keratinaceous plugs form in the hair follicle infundibula
• Forming comedomes
• Common in demodicosis and endocrinophathies

Question 5

What is hyperkeratosis?

Answer 5

-Increased depth of the cornified layer

Question 6

What causes aconthosis and hyperkeratosis? (i.e. pressure sores)

Answer 6

-Repeated low grade blunt trauma causes a release of cytokines from the keratinocytes which increase division of the basal epidermal cells

Question 7

Which cytokines do keratinocytes produce?

Answer 7

• PDGF

- TGF-a

Question 8

What is acanthosis?

Answer 8

Increased depth of epidermis (e.g. dog elbow sores)

Question 9

What is lichenification?

Answer 9

Thickening/ hardening of the skin -> characterised by very obvious markings and lines.

Question 10

What is a vesicle?

Answer 10

• Fluid filled blister less more than 0.5mm?

- Often associated with viruses or may be autoimmune disease

Question 11

What is a pustule?

Answer 11

Small circular elevation of the epidermis that is pus filled.
Usually involved with infections

Question 12

What can result in hyperpigmentation?

Answer 12

• Commonly due to inflammation

- Can also be caused by some endocrine skin disorders e.g. Sertoli cell tumours.

Question 13

What is crusting?

Answer 13

• Dried exudate, cells, serum etc adheres to skin surface

- Has many causes

Question 14

What is an erythema?

Answer 14

Reddening of the dermis as a result of damage which stimulates release of pro inflame mediators. These trigger vasodilation of dermal vessels.
-Common in infectious and allergic processes

Question 15

Describe dermal oedemas

Answer 15

• They involve cytokines, primarily histamine which increase the vascular permeability causing leakage of tissue fluid
• The ‘pit’ when pressure is applied
• Often caused by type 1 hypersensitivity but has other causes too

Question 16

What is the common name for uticaria?

Answer 16

Hives

Question 17

Why does chronic inflammation result in dermal thickening?

Answer 17

-increases collagen and other CT components

Question 18

Why do Sertoli cell tumours result in alopecia?

Answer 18

-Excess oestrogens produced which result in the alopecia