dermpath erosive, depigmenting

Question 1

Erosive and depigmenting diseases
- basic principle
- caused by?

Answer 1

Basic principle: input : output balance
◼ greater loss or less produced
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Caused by 3 DermPath Patterns
◼ Vesiculopustular dermatitis
◼ Epidermal cytotoxic (interface) dermatitis
◼ Vasculitis

Question 2

The Language of Skin:
- Macule definition
- histo pattern

Answer 2

• A Macule is a circumscribed, non- palpable, up to 1 cm diameter lesion that is the result of alteration of the skin pigmentation
• Lentigenes (“freckles”) are examples of pigmented macules.
• Histological term: HYPERPIGMENTATION - localised

Question 3

The Language of Skin:
- Leukoderma definition
- histo?

Answer 3

• Leukoderma is a lack of pigmentation of skin, sometimes referred to as depigmentation or vitiligo
• Histological term: LOSS OF PIGMENT, PIGMENTARY INCONTINENCE

Question 4

The Language of Skin:
Excoriation/ulcer?
histo term?

Answer 4

• Excoriation is partial loss of epidermis
• Ulceration is full thickness loss of epidermis
• Histological term: EROSION or ULCERATION

Question 5

DERMPATH pattern:
5. CYTOTOXIC / INTERFACE DERMATITIS
- causes

Answer 5

◼ Immune mediated diseases
◼ Adverse reaction to drugs
◼ Toxic reaction
◼ Physicochemical injury
◼ Idiopathic

Question 6

CYTOTOXIC / INTERFACE DERMATITIS - presentation

Answer 6

often presents as a depigmenting (leukoderma) or ulcerative condition

Question 7

CYTOTOXIC / INTERFACE DERMATITIS
- targets / pathogenesis, different ways it can occur and diseases implicated
- what can mimic this?

Answer 7

Disease targets keratinocytes causing single cell death.
◼ Diseases targeting stratum basale (basal)
> Cutaneous lupus erythematosis (CLE) Such as Discoid lupus erythematosus (DLE)
◼ Diseases targeting all levels (transepidermal)
> Erythema multiforme - like (EM)
> Toxic epidermal necrosis/Stevens Johnson syndrome – ‘drug’ reactions
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◼ Fungal dermatitis and superficial pyoderma can mimic this.

Question 9

DERMPATH pattern: 7. VASCULITIS
◼ Causes, broadly

Answer 9

Infectious
◼ Virus
◼ Bacteria (sepsis)
◼ Fungal
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Noninfectious
◼ Immune mediated (Type 3 hypersensitivity)
◼ Breed associated

Question 9

VASCULITIS - common bacterial and viral diseases / pathogens in pigs
- common pathogens / conditions in other animals

Answer 9

◼ Sepsis
> Diamond skin disease of pigs
◼ Viral
> Porcine circovirus, EVA, MCF
◼ Purpura hemorrhagica > rare complication of equine strangles
◼ Immune mediated
◼ Breed associated
> Jack Russell terrier
> German shepherd
> Dermatomyositis of collie breeds
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- any time the target is blood vessels, can be skin lesions

Question 10

classic lesion of vasculitis

Answer 10

Fibrinoid necrosis of the vessel wall

Question 11

VASCULITIS – clinical correlates

Answer 11

• Footpad ulcers - Central location
• Ear margins