Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Y4 SA - Dermatology > Immune mediated skin disease > Flashcards

Immune mediated skin disease Flashcards

1
Q

What is an immune mediated skin disease?

A

The immune system fails to tolerate self antigens and it mounts a response against normal skin components

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is a primary immune mediated skin disease?

A

No identifiable trigger factor present = idiopathic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is a secondary immune mediated skin disease?

A

Exogenous trigger antigen, most commonly drug, bacteria or virus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How you should patients with potential immune mediated skin disease be clinically assessed?

A
  • Consider signalment (particularly breed) & key historical features
  • Look for primary lesions
  • Look at distribution of lesions
  • Make differential diagnosis list
  • Run tests according to differentials
  • Interpret results in line with clinical findings
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

List some diagnostic tests that can be used to diagnose immune mediated skin disease

A
  • Skin scrapes & trichography
  • Lesion cytology
  • Bacterial/fungal culture and susceptibility testing
  • Haematology, biochemistry: to give a general picture of the animal’s heath before treatment
  • Urinalysis
  • Diagnostic imaging: radiography, ultrasonography
  • Blood smear cytology
  • Coombs test
  • Antinuclear antibody (ANA) test
  • Skin biopsy & histopathology
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How is cytology used to narrow down the DDX

A

Cytology to differentiate sterile from infectious disease (and rule out secondary bacterial infection)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How is skin biopsy and histopathy used to narrow down the DDX

A

Rule out neoplasia, atypical infectious diseases and determine skin pathology (definitive diagnosis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the advantages of cytology

A

Easy, cheap, rapid (in house) results
Differentiate sterile from septic (infectious) disease
Determine type of inflammation
May inform management prior to histopath results

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Mixed neutrophils and macrophages indicate what type of inflammation?

A

Sterile pyogranulomatous inflammation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Neutrophils with cocci bacteria indicate what type of inflammation?

A

Coccoid bacterial inflammation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Direct impression smears can be used for which lesion types?

A

Pustules, exudative lesions (erosions, ulcers), draining tracts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

FNA can be used for what types of lesions?

A

Nodules, plaques, tumours, lymph nodes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

When in the diagnostic process in skin biopsy and histopathology used?

A

Test often comes after cytology once the differential list has been narrowed down

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Where are samples taken when doing skin biopsies?

A
  • Take multiple biopsies +3
  • Sample primary lesions
  • Sample range of lesions to represent disease process
  • Sample whole lesion where possible
  • Avoid eroded / ulcerated lesions (or sample from margin to include epidermis) - If only these lesions are present you need to sample from the lesion margins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Name the 4 most common primary lesions seen in immune mediated skin disease

A
  • Pustules
  • Plaques/nodules
  • Erythematous macules/patches
  • Hypopigmented macules/patches
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

List some other lesions seen in immune mediated skin disease

A

Alopecia
Vesicles
Erosions/ulcers
Crusts
Purpura
Scale

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Define an erosion

A

Loss of the surface layer of the epidermis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Define an ulcer

A

Loss of full thickness of the epidermis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Are ulcers and erosions primary or secondary lesions?

A

Secondary
- less helpful in making DDx

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the most common causes of ulcers and erosions?

A

Keratinocyte death, loss of KC adhesion, self trauma (pruritus), secondary bacterial infections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are crusts?

A

Dried exudate on skin surface
- Pus from pustules
- Exudate from erosions/ulcers
- Blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Define a pustule

A

A circumscribed elevation of skin containing pus
Pus is formed from infiltrating neutrophils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Case 1:
- Physical examination = General WNL except pyrexia 40oC and mild peripheral lymphadenomegaly
- Lesion morphology = Rare pustule, thick, adherent crusts, pus, erosions
- Lesion distribution = Multifocal - Dorsal muzzle, periocular, medial pinnae, footpads

What are the 4 DDx?

A
  • Bacterial infection (pyoderma/folliculitis)
  • Pemphigus foliaceus
  • Superficial pustular drug reaction (rare)
  • Superficial pustular dermatophytosis (rare)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are acantholytic keratinocytes?

A

Large epithelial cells (larger than neutrophils) – rounded (normal keratinocytes are normally anuclear and angular)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Describe the pathophysiology of canine pemphigus foliaceous
- Auto-antibodies (mainly IgG) target components of desmosomes that link keratinocytes in superficial epidermis - Separation of KCs > acantholytic ‘rounded up’ KCs - Neutrophilic inflammatory response > superficial pustules with free floating acantholytic KCs
26
Describe the appearance of pemphigus foliaceous on histopathology
Subcorneal (superficial) pustular dermatitis with acantholytic keratinocytes
27
Name the most common autoimmune skin disease of dogs
Pemphigus foliaceus
28
Describe the signalment of pemphigus foliaceus
Middle aged (any), predisposed breeds akita, chow chow, cocker spaniel, dachshund, Labrador retriever, British bulldog & Shetland sheep dog (affects many breeds)
29
Describe feline pemphigus foliaceous
- Less common than dog PF - Signalment: X - Lesion distribution: face, claw fold (paronychia) and nipples - Prognosis fair
30
Define a plaque
Flat elevation of skin more than 1cm in diameter. Cause by infiltration of cells of coalition of papules
31
Define a nodule
Circumscribed solid elevation > 1cm diameter, usually extending into deeper skin layers. Caused by massive infiltration of cells
32
Describe the signalment of Eosinophilic furunculosis of the face
Young adults
33
How does Eosinophilic furunculosis of the face present?
History: rapid onset, intense pruritus Lesion morphology: eroded/ulcerated plaques and nodules Distribution: face Cytology: eosinophilic inflammation Histopathology: eosinophilic folliculitis & furunculosis
34
Describe the signalment of Sterile granulomatous dermatitis and lymphadenitis (juvenile cellulitis)
Puppies (sporadic cases in adults)
35
How does Sterile granulomatous dermatitis and lymphadenitis (juvenile cellulitis) present?
History: acute onset, non-pruritic (painful), pyrexia, lethargy Lesion morphology: follicular nodules (furuncules) & plaques (often eroded & crusted), diffuse swelling, alopecia (check for Demodex), lymphadenomegaly Distribution: face (muzzle, periocular, pinnae), lymph nodes
36
Describe the cytology and histology of Sterile granulomatous dermatitis and lymphadenitis (juvenile cellulitis)
FNA cytology: sterile pyogranulomatous inflammation Histopath: sterile perifollicular granulomatous-pyogranulomatous inflammation & furunculosis
37
Define a macule
flat area of skin discolouration < 1cm diameter
38
Define a patch
flat area of discolouration > 1cm diameter
39
List 3 DDx of Hypopigmented or erythematous macules & patches
Hypopigmentation, erythematous macules/patches, erosions/ulcers
40
Describe the clinical presentation of facial discoid lupus erythematous
- Loss of cobblestone surface - Hypopigmented macules and patches - Erosions, ulcers and crusting - Black to blue to pink pigmentary change - Note biopsies taken from blue pigmentary change rather than ulcers or crusting - Hypopigmentation, erosion, crusting periocular skin and lips - Severe ulceration and crusting
41
Describe the history of an animal with Erythema multiforme (major/minor)
Acute onset, non-pruritic, +/- systemic signs (pyrexia, lethargy, inappetence) Trigger: virus, drug, vaccine, microbial infection, neoplasia, systemic disease, food (can be idiopathic)
42
Describe the lesions seen in cases of Erythema multiforme (major/minor)
- Primary lesion = annular erythematous macule (may be targetoid) - Can see vesicles, bullae, wheals, ulceration, crusts - Distribution: ventral abdomen > generalised, mucosae (often oral cavity)
43
Describe the 'target lesions' seen in erythema multiforme major/minor
Erythematous macules spread peripherally producing annular or arciform pattern - Central erythema/pupura, ring of clear oedema (may be raised), ring of erythema = target lesion - Centre may be a vesicle/bulla resulting in ulcers and crusts
44
Describe the cytology and histopathology of erythema multiforme major/minor
Cytology: sterile non-specific inflammation (NB ulcers may be secondarily infected!) Histopathology: keratinocyte apoptosis (death), lymphocyte satellitosis, interface (epidermis/dermis) dermatitis
45
The degree of apoptosis in erythema multiforme determines?
Severity of epithelial loss i.e. EM vs SJS vs TEN
46
Describe the main features of hyperkeratotic erythema multiforme
Chronic, persistent Older dogs Idiopathic Lesions more exudative and crusting Often face and ears but can be generalised
47
Describe Stevens-Johnson syndrome
Erythema multiforme No target lesions More ulcerative – lose large sections of skin Guarded prognosis
48
What is the signalment of Uveodermatologic syndrome
young to middle aged, Akita predisposed
49
Describe the history and clinical presentation of Uveodermatologic syndrome
History: acute bilateral uveitis, non-pruritic Lesion morphology: hypopigmented macules > patches, erythematous macules, erosions, ulcers, crusts Distribution: face; nose, lips, periocular skin (occasionally footpads, scrotum, perineum)
50
List the DDx for immune mediated alopecia
Sebaceous adenitis Alopecia areata Dermatomyositis Ischaemic dermatopathy Post-injection alopecias
51
Which test is used to rule out demodicosis and dermatophytosis?
Trichography +/- skin scrapes
52
Describe the signalment of sebaceous adenitis
Standard poodle*, Akita*, vizsla, *autosomal recessive mode of inheritance
53
How does sebaceous adenitis present?
History: non-pruritic unless SBI Lesion morphology: partial alopecia and poor coat quality, follicular casts and scale Distribution: generalised
54
Describe the cytology and histopathology of sebaceous adenitis
Cytology: no significant findings unless SBI Histopath: pyogranulomatous inflammation targeting sebaceous glands > destruction of sebaceous glands and hair follicle atrophy
55
Describe how cases of alopecia areata present
History: non pruritic, chronic onset Lesion morphology: focal to multifocal, partial to complete patches of alopecia +/- erythema and hyperpigmentation Distribution: head/face
56
Describe the histological appearance of alopecia areata
Lymphocytic destruction of hair bulbs
57
Describe the signalment of Dermatomyositis/ischaemic dermatopathy
Young collies, SSD, Beauceron shepherd, Belgian shepherd, PWD predisposed to dermatomyositis (familial)
58
Describe the clinical presentation of Dermatomyositis/ischaemic dermatopathy
History: non-pruritic, chronic course +/- myositis Quite a rare disease Lesion morphology: focal to multifocal alopecia with variable hyperpigmentation, hypopigmentation, scaling, erosion/ulceration & crusting Distribution: face and extremities (dorsal digits, pinnae & tail tips, nails)
59
Describe the histological appearance of Dermatomyositis/ischaemic dermatopathy
Chronic dermal & vascular inflammation > follicular atrophy (include muscle in biopsy to check myositis)
60
How is immune mediated disease managed?
- Removal/treatment of any external triggers e.g. Drugs, UV light: sunscreen, food - Control of inappropriate immune response: Immunosuppressive/immunomodulatory drugs

Y4 SA - Dermatology (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions