Derm #2 Flashcards by Bianca Zayas

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

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

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

Excessive thickness or hyperplasia of the stratum corneum;

Seen in mild, chronic irritation;

Can be focal (callus) or generalized

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What is focal hyperkeratosis called?

callus

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What is orthokeratosis?

Hyperkeratosis of normally appearing keratin layers

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What is parakeratosis?

Retention of cell nuclei within the keratin

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

Acanthosis, chronic

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What change is seen here?

Pustule - sub-cornual (sits beneath stratum corneum)

If only this is present then the change is very acute

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

orthokeratotic hyperkeratosis (arrow);

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

Change is chronic

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What is acantholysis and what can it be caused by?

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

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What is spongiosis and what does it lead to?

Intercellular edema in the epidermis; leads to vesicle formation

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

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

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When is ballooning degeneration commonly seen?

In pox diseases of skin

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

Ballooning degeneration (black arrow);

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

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What are the arrow heads pointing to?

acantholytic keratinocytes

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What is the arrow head pointing to?

acantholytic keratinocyte

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What occurs during Pemphigus foliaceus?

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

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What is change 1?

hyperkeratosis

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What is change 2?

Acanthosis

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

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

What is happening here?

Juvenile pyoderma (face swells, animal gets febrile)

What are characteristics of dermatitis?

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

Why should you look for patterns in dermatitis?

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

What are selected patterns of dermatitis?

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

How can you characterize perivascular inflammation?

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

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

Inflammation is inside the vessel, vessel wall inflamed, can be caused by sepsis; EX: diamond skin disease in pigs

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

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

How can you characterize a hyperplastic pattern of inflammation?

Acanthosis, very common, cannot tell much about the cause

What two patterns of inflammation go together?

luminal folliculitis and furunculosis

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

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

How can you characterize furunculosis?

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

How can you characterize an epidermal pustule?

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)

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

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)

What type of dermatitis is seen here?

perivascular

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

interface; discoid lupus

What type of dermatitis is seen here?

Folliculitis that has progressed to furunculosis

What gross lesions can be seen with acute dermatitis?

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

What microscopic lesions can be seen with acute dermatitis?

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

What can happen during resolution of acute dermatitis?

Complete restitution, scarring, or progression to chronic inflammation

What change is seen here?

Acute dermatitis, pyoderma, erythema, ruptured pustules

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

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

What causes greasy pig disease?

Severe superficial cutaneous infection with Staph. hyicus

What are gross lesions seen with chronic dermatitis?

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

What are micro lesions seen with chronic dermatitis?

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

What can occur during resolution of chronic dermatitis?

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

What can be seen here?

chronic dermatitis: alopecia, epidermal thickening, scale, crust

What is happening here?

Demodicosis: alopecia, thickened skin, crust

What is happening here in this bovine?

Thickened hyperplastic skin - coalescing nodules or plaque, hyperkeratinized (Stephanofilaria)