Study guide integument (Ginn)

Question 1

Function of the skin

Answer 1

• Temp and blood pressure regulation
• fluid regulation
• protection barrier to outside world
• sensation
• nutrient metabolism: Vit D
• Immune functions: SALT

Question 2

Layers of skin

Answer 2

• Epidermis
  
  • surface of skin
  • cell turnover ~ 10 days
• Dermis
  
  • made of collagen and elastin
• Adnexa
  
  • hair follicles
  • apocrine glands (sweat glands)
  • halocrine glands (sebaceous glands)
  • mammary glands
• Panniculus
  
  • subcutis

Question 3

Epidermis

Answer 3

• Stratum corneum (top)
• +/- stratum lucidum
• Stratum granulosum
• Stratum spinosum
  
  • contains melanocytes
• Stratum basale (bottom)

Question 4

Diagnostic approach

Answer 4

• Signalment
• history: duration, pruritis, other animals
• Response/failure to tx
• overall health status

Question 5

Primary/secondary lesion

Answer 5

• Primary lesion
  
  • best for bx
• Secondary lesion
  
  • evolution of primary lesion over time

Question 6

epidermal response to injury

Acanthosis

Answer 6

• Acanthosis
  
  • hyperplasia of cells in epidermis
  • usually stratum spinosum
• regular: rare
• irregular: most common
  
  • yeast infection
• Papillated
  
  • papillomas or warts
• Psuedocarcinomatosis
  
  • severe, chronic trauma

Question 7

epidermal response to injury

hyperkeratosis

Answer 7

• hyperkeratosis
  
  • inc width of stratum corneum
• orthokeratotic
  
  • buildup of excess keratin after normal cornification
  • no nuclei
• perakeratotic
  
  • thickening of stratum corneum with retention of nuclei
• Disease
  
  • ichtyosis: congenital skin disorder, skin thickened with scales, hyperkeratosis crack into plates resembling fish scales
  • superficial necrolytic dermatitis
  • seborrhea

Question 8

epidermal response to injury

dyskeratosis

Answer 8

• dyskeratosis
  
  • prematur keratinization of cells in epidermis
  • often seen wtih parakeratosis
  • cells rounded up, hypereosinophilic, nuclear degeneration

Question 9

epidermal response to injury

apoptosis

Answer 9

• apoptosis
  
  • individual programmed cell death
• diseases
  
  • SLE
  • erythema multiforme
  • UV light damage

Question 10

epidermal response to injury

necrosis

Answer 10

• necrosis
  
  • can be partial/full thickness
• causes
  
  • adverse drug rxns: toxic epidermal necrolysis

Question 11

epidermal response to injury

cutaneous atrophy

Answer 11

• cutaneous atrophy
  
  • decreases in number and size of cells
  • most common cause is endocrine dz

Question 12

epidermal response to injury

Edema

Answer 12

• Edema
  
  • fluid in between cells of epidermis or within individual cells of epidermis
• Intercellular
  
  • spongiosis: widening of spaces between keratinocytes
• Intracellular: fluid accumulation in the cells
  
  • hydropic degeneration: at dermal-epidermal junction, causes separation of cells
  • ballooning degeneration: at superficial layers of the epidermis.
    
    • vesicle could form
    • often associated with viral infections

Question 13

epidermal response to injury

Acantholysis

Answer 13

• acantholysis: loss of cohesion between keratinocytes due to breakdown of cell-to-cell attachments
  
  • type II hypersensitivity: Pemphigus foleaceous
  • enzymatic destruction: bacterial infection

*pemphigus foleaceous: primar lesion: pustule; secondary lesion: acantholysis

Question 14

epidermal response to injury

crusts

Answer 14

• crusts
  
  • surface collection of plasma, leukocytes
  • most vesicles, bullae and pustules for and then crust is secondary lesion

Question 15

epidermal response to injury

vesicles/bullae

Answer 15

• Vesicles/bullae
  
  • fluid filled spaces at the epidermis or epidermal/dermal junction
• pathogenesis
  
  • marked spongiosis, hydropic or ballooning degeneration
  • enzymatic destruction
  • immune destruction-acantholysis or other
  • mechanical destruction-burn, friction
  • genetic structural defects

Question 16

epidermal response to injury

Pustules

Answer 16

• pustule
  
  • collection of fluid and inflammatory cells in epidermis or sub-epidermis region
• Neutrophilic:
  
  • bacterial and some autoimmune dzs
• Eosinophils:
  
  • parasitic dz, allergic, immune, microbial, some idiopathic
• Pautrier’s microabscesses:
  
  • collection neoplastic lymphocytes in epidermis
  • specific for mycoses, fungoides/epitheliotrophic cutaneous lymphoma

Question 17

epidermal response to injury

changes in pigmentation

Answer 17

• hyperpigmentation:
  
  • chronic inflammation or idiopathic
• hyperpigmentation:
  
  • damage to melanocytes or basement membrane zone
  • defects in formation of melanin of lack of melanocytes

Question 18

Follicular changes

Hyperkeratosis

Answer 18

• Hyperkeratosis: similar to epidermal
  
  • primary seborrhea
  • vit A responsive dermatosis
  • endocrine dermatosis
  • others

Question 19

epidermal response to injury

atrophy

Answer 19

• atrophy: shrinking of hair follicles
  
  • endocrinopathies
  • ischemia
  • traction

Question 20

epidermal response to injury

Folliculitis

Answer 20

• Folliculitis: inflammation of the hair follicle
  
  • folliculocentric papules
  • patchy alopecia
• Cause folliculitis in dogs
  
  • Demodex
  • dermatophytes
  • bacteria
• Cause of folliculitis in cats
  
  • dermatophytes

Question 21

epidermal response to injury

furunculosis

Answer 21

• furunculosis: wall of follicle is destroyed by infiltrate and contents of hair follicle are in dermis
  
  • folliculocentric nodule
  • can have ulcerative draining lesions

Question 22

epidermal response to injury

dysplasia

Answer 22

• dysplasia
  
  • abnormal development of hair follicle that leads to alopecia

Question 23

Dermal response to injury

edema

Answer 23

• edema
  
  • uticaria: hives
  • angioedema: edema of dermis and subcutis
  • type I hypersensitivity rxn
    
    • insect bites
    • vax rxns
    • food allergy
    • atopy
    • drug rxns

Question 24

dermal response to injury

mucinosis

Answer 24

• mucinosis: stringy characteristic to dermis
  
  • inc amount leads to puffy looking skin
  • sharpeis have inc mucin

Question 25

dermal response to injury

collagen

Answer 25

• collagen
  
  • fibrosis
  • degeneration/collagenolysis
  • mineralization
    
    • often dystrophic mineralization in hyperadrenocorticism (calcinosis cutis)

Question 26

subcutis response to injury

panniculitis

Answer 26

• panniculitis
  
  • inflammation of the panniculus

Question 27

subcutis response to injury

fat necrosis

Answer 27

• fat necrosis
  
  • may occur anytime there is inflammation

Question 28

Vessel response to injury

vasodilation

Answer 28

• vasodilation
  
  • may lead to erythema, edema

Question 29

Vessel response to injury

vasculitis

Answer 29

• vasculitis
  
  • thrombosis
  • ischemia
  • edema
  • hemorrhage
  • atrophy

Question 30

BX

Answer 30

• devastating dz
• neoplasm
• unsuccessful treatments
• no clue about the dz
• quick answer
• primary lesions: leading margins, edges of ulcers, crusts
• multiple sites

Question 31

Cellular infiltrates

Answer 31

• neutrophils: active inflammation
• Eosinophils: allergic or ectoparasites
• Mononuclear phagocytes: persisten antigen in tissue
  
  • macrophages
  • epitheliod macs
  • multinucleated giant cells
• Lymphocytes/plasma cells: indicates local/systemic antigen stim
  
  • type IV hypersensitivity
• Mast cells: some normal, too many = IgE mediated hypersensitivity

Question 32

Perivascular dermatitis

Answer 32

• Most common type dermatitis
• aggregates of inflammatory cells around hair follicles
• generic inflammatory response

Question 33

Types of perivascular dermatitis and assoc dz

Answer 33

• Eosinophils
• Irregular epidermal hyperplasia
  
  • acral lick dermatitis
  • flea bite hypersensitivity
  • sarcoptic mange
  • atopic dermatitis
• orthokeratotic hyperkeratosis
  
  • seborrhea
  • icthyosis
• parakeratotic hyperkeratosis
  
  • Zn responseive dermatitis
  • malassezia dermatitis
• severe ulceration
  
  • hot spot
  • photosensitization

Question 34

Interface dermatitis

about

Answer 34

• inflammation at interface between epidermis and dermis
• target: anything in basal layer, epidermal junction
• hydropic degeneration/apoptosis in basal layer
• bands of lymphs, plasma cells, macs at epidermal/dermal juncton
• pigmentary incontinence
• +/- vesicles at interface

Question 35

Interface dermatitis

Pathogenesis

Answer 35

• cytotoxic T cll attack on keratinocytes, melanocytes or basement membrane components
• non-immune mediated damage
• unknown

Question 36

Interface dermatitis

Diseases

Answer 36

• Toxid Epidermal Necrosis (TEN)
• Erythema multiforme (EM)
• Systemic lupus erythematosus (SLE)
• Uveodermatologic syndrome (VKE)

Question 37

Vasculitis

about

Answer 37

• leukocytes within the walls of capillaries and venules
• will see evidence of vessel damage
• edema, necrosis/thrombosis, leukoclasis
• mild damage
  
  • atrophy and alopecia
• severe damage
  
  • cutaneous infarction and ulceration
• if multicentric
  
  • lesions at extremities (places with little collateral blood flow)
    
    • tail, footpads, ears

Question 38

Vasculitis

pathogenesis

Answer 38

• Type III hypersensitivity: immune complex deposition in vessels
• primary bacterial skin disease
• bacterial septicemia
• systemic infection with endotheliotropic organisms such as rickettsia
• rabies vax assoc vasculitis

Question 39

Nodular to diffuse dermatitis

about

Answer 39

• Dermis +/- panniculus infiltrates of leukocytes
• types of leukocytes present help point to a cause

Question 40

Nodular to diffuse dermatitis

pathogenesis

Answer 40

• persistence of antigen in tissue stimulates cell mediated immune response
• Gross lesions: multiple papules, nodues
• Fungi: zygomycetes , deep pyoderma, higher bacteria
• Parasites, protozoans
• Oomycetes: pythum, lageridium
• Algae
• Idiopathic: sterile
• foreign material
• neoplasms
• Histiocytic disorders
• eosinophilic granulomas

Question 41

Vesicular or pustular dermatitis

about

Answer 41

• Intradermal
  
  • subcorneal: pemphigus folliaceous, superficial pyoderma
  • suprabasilar: pemphigus vulgaris (row of tombstones)
• Subepidermial
  
  • burns, SLE, TEN, Bullous pemphigoid

Question 42

Vesicular or pustular dermatitis

pathogenesis

Answer 42

• Marked spongiosis, hydropic or ballooning degeneration
• Enzymatic destruction
• Immune destruction
• Mechanical destruction: burn, friction
• Genetic: structural defects

*Level of vesicle formation, degree and type of cellular infiltrate, signalment and distribution of lesions all are needed to determine the disease present

Question 43

Folliculitis

Answer 43

• inflammation of the hair follicle
• folliculocentric papules, patchy alopecia
• cause of folliculitis in dogs:
  
  • demodex
  • dermatophytes
  • bacterial infection
• cause of folliculitis in cats
  
  • dermatophytes

Question 44

Furunculosis

Answer 44

• wall of follicle is destroyed by infiltrate and contents of hair follicle are in dermis
  
  • folliculocentric nodule
  • can have draining lesions

Question 45

Atrophic dermatoses

about

Answer 45

• symmetric hypotricosis, think skin
• comedones (black heads)
• Telangiectasia (vessels in skin are very torturous)
• Hyperpigmentation (inc pigment)

Question 46

Atrophic dermatoses

pathogenesis

Answer 46

• hormonal imbalance (hyperadrenocorticism, hypothyroidism, sex hormone imbalance)
• ischemia: if focal
• need additional clinical and biochem info for definitive diagnosis