Derm #2

Question 1

What is acanthosis, what can be seen with it, and what is it a common response to?

Answer 1

Thickening due to hyperplasia of the epidermis, especially in the stratum spinosum;

Down growth and enlargement of rete pegs is seen;

Common response to chronic irritation

Question 2

What is hyperkeratosis, is it acute or chronic, and what is its distribution?

Answer 2

Excessive thickness or hyperplasia of the stratum corneum;

Seen in mild, chronic irritation;

Can be focal (callus) or generalized

Question 3

What is focal hyperkeratosis called?

Answer 3

callus

Question 4

What is orthokeratosis?

Answer 4

Hyperkeratosis of normally appearing keratin layers

Question 5

What is parakeratosis?

Answer 5

Retention of cell nuclei within the keratin

Question 6

What change is seen here and is it acute or chronic?

Answer 6

Acanthosis, chronic

Question 7

What change is seen here?

Answer 7

Pustule - sub-cornual (sits beneath stratum corneum)

If only this is present then the change is very acute

Question 8

What is indicated by the arrow? The star? Is this change acute or chronic?

Answer 8

orthokeratotic hyperkeratosis (arrow);

There is so much keratin present that it has started to plug up the hair follicle (star);

Change is chronic

Question 9

What is acantholysis and what can it be caused by?

Answer 9

Loss of cohesion bt epidermal cells due to degeneration of desmosomes; caused by autoimmune disease (EX: Pemphigus)

Question 10

What is spongiosis and what does it lead to?

Answer 10

Intercellular edema in the epidermis; leads to vesicle formation

Question 11

What is ballooning degeneration and what can it lead to formation of?

Answer 11

Intracellular edema or hydropic degeneration of epidermal cells; areas so affected often coalesce to form vesicles

Question 12

When is ballooning degeneration commonly seen?

Answer 12

In pox diseases of skin

Question 13

What is seen here demarcated by the black arrow? Red arrows?

Answer 13

Ballooning degeneration (black arrow);

Skin pale and swollen, filled with water, starts to swell and eventually forms large vesicles (red arrows)

Question 14

What are the arrow heads pointing to?

Answer 14

acantholytic keratinocytes

Question 15

What is the arrow head pointing to?

Answer 15

acantholytic keratinocyte

Question 16

What occurs during Pemphigus foliaceus?

Answer 16

Acantholysis occurs in the subcorneal epidermis, resulting in release of freefloating keratinocytes in subcorneal vesicles and pustules

Question 17

What is change 1?

Answer 17

hyperkeratosis

Question 18

What is change 2?

Answer 18

Acanthosis

Question 19

What is happening in this horse and what is likely the cause?

Answer 19

Pustules; some have opened around the eyes and formed crusts; likely caused by Pemphigus foliaceus

Question 20

What is happening here?

Answer 20

Juvenile pyoderma (face swells, animal gets febrile)

Question 21

What are characteristics of dermatitis?

Answer 21

Localized or generalized, primary or secondary, usually dermis and epidermis involved, location of inflammation - response to injury (patterns)

Question 22

Why should you look for patterns in dermatitis?

Answer 22

To group diseases that cause a particular pattern and to form differentials based on those patterns

Question 23

What are selected patterns of dermatitis?

Answer 23

Perivascular and vascular, follicular, epidermal hyperplasia, interface, pustular, and nodular

Question 24

How can you characterize perivascular inflammation?

Answer 24

Around blood vessels in the dermis, very common, can be caused by allergy

Question 25

How can you characterize vascular inflammation and what is an example?

Answer 25

Inflammation is inside the vessel, vessel wall inflamed, can be caused by sepsis;

EX: diamond skin disease in pigs

Question 26

How can you characterize an interface pattern of inflammation and what can it be caused by?

Answer 26

Inflammatory cells located at the junction of dermis and epidermis; can be caused by autoimmune disease such as discoid lupus

Question 27

How can you characterize a hyperplastic pattern of inflammation?

Answer 27

Acanthosis, very common, cannot tell much about the cause

Question 28

What two patterns of inflammation go together?

Answer 28

luminal folliculitis and furunculosis

Question 29

How can you characterize luminal folliculitis as a pattern of inflammation?

Answer 29

Damage inside a hair follicle, caused by demodex (mites), dermatophytes (ringworm), deep bacterial infections

Question 30

How can you characterize furunculosis?

Answer 30

Luminal folliculitis that gets so bad that the follicle ruptures, anything that was causing it will go into the dermis and incites tremendous inflammation; it is painful, itches, and swells

Question 31

How can you characterize an epidermal pustule?

Answer 31

Can be caused by superficial bacterial infections such as streps and staphs, can be caused by secondary bacterial infections, can be caused by Pemphigus (autoimmune)

Question 32

How can you characterize a nodular to diffuse pattern of inflammation?

Answer 32

Usually has macrophages present, opportunistic pathogens come in through bite wounds or foreign bodies, can also be caused by systemic fungal infections (yeast, blastomycosis, pithiosis)

Question 33

What type of dermatitis is seen here?

Answer 33

perivascular

Question 34

What type of dermatitis is seen here and what disease might look like this?

Answer 34

interface; discoid lupus

Question 35

What type of dermatitis is seen here?

Answer 35

Folliculitis that has progressed to furunculosis

Question 36

What gross lesions can be seen with acute dermatitis?

Answer 36

Erythema, vesicles, pustules, wheals, exudation, crusts, ulcers, traumatic alopecia

Question 37

What microscopic lesions can be seen with acute dermatitis?

Answer 37

Spongiosis, ballooning degeneration, vesicles, pustules, dermal edema, vascular dilation and congestion, necrosis, fibrin, thrombosis, acute inflammatory infiltrates

Question 38

What can happen during resolution of acute dermatitis?

Answer 38

Complete restitution, scarring, or progression to chronic inflammation

Question 39

What change is seen here?

Answer 39

Acute dermatitis, pyoderma, erythema, ruptured pustules

Question 40

What change is seen here and what is the common name?

Answer 40

Acute, diffuse, serofibrinous and pustular dermatitis; AKA exudative epidermitis, AKA greasy pig disease

Question 41

What causes greasy pig disease?

Answer 41

Severe superficial cutaneous infection with Staph. hyicus

Question 42

What are gross lesions seen with chronic dermatitis?

Answer 42

scale, epidermal thickening - hyperplasia, lichenification, pigmentary changes, alopecia, fibrosis

Question 43

What are micro lesions seen with chronic dermatitis?

Answer 43

Acanthosis, hyperkeratosis, fibrosis, chronic (mononuclear) cellular infiltrates – macrophages, plasma cells, lymphocytes

Question 44

What can occur during resolution of chronic dermatitis?

Answer 44

Complete resolution (but more difficult than acute), persistent chronic inflammation, fibrosis and scarring, depigmentation

Question 45

What can be seen here?

Answer 45

chronic dermatitis: alopecia, epidermal thickening, scale, crust

Question 46

What is happening here?

Answer 46

Demodicosis: alopecia, thickened skin, crust

Question 47

What is happening here in this bovine?

Answer 47

Thickened hyperplastic skin - coalescing nodules or plaque, hyperkeratinized

(Stephanofilaria)