Psthology of Rashes Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

what is the endocrine function of the skin?

A

UV stimulation of vitamin D

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

what happens when cells become corneocytes?

A

nuclei are lost

cells are then shed from the upper surface of skin

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

what is contained within the granular layer?

A

keratohyalin granules

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

what do melanocytes do and how?

A

synthesise melanin pigment and transfer it to keratinocytes via dendritic processes
found in basal layer

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

what do Langerhans cells do?

A

found in upper and mid-dermis and act as sentinels monitoring environment for antigens and initiate inflammation through dendritic function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what are the 2 parts of the dermis?

A

papillary dermis = thin superficial layer

reticular dermis = thicker deeper layer containing type 1 collagen and skin appendages

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

what is the epidermal basement membrane made of?

A

laminin and collagen 4

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

what holds the dermis onto the epidermis?

A

hemi-desmosomes at the dermo-epidermal junction

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

what is parakeratosis?

A

persistence of nuclei in cells in the keratin layer - sign that epidermal turnover is too fast - psoriasis

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

what is acanthosis?

A

increased thickness of epithelium

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

what is papillomatosis?

A

irregular epithelial thickening

growth of dermal papilla upwards into the epidermis

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

what is spongiosis?

A

oedema fluid between squamous cells of the epidermis, increasing the prominence of intracellular prickles
hallmark of eczema

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

what are the 4 main reaction patterns of inflammatory skin disease?

A

spongiotic-intraepidermal oedema - eczema
psoriasiform - elongation of rete ridges - psoriasis
lichenoid - basal layer damage - lichen planus, lupus
vesiculobullous - blistering - pemphigoid, pemphigus, dermatitis herpatiformis

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

describe the pathogenesis of psoriasis

A

increased epidermal turnover leads to epidermal hyperplasia
complement attracts neutrophils to keratin layer
koebner phenomenon
hereditary factors (specific HLA types)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what are some features of psoriasis plaques?

A

well defined
erythematous as blood vessels run close to the top due to dermal papillae
symmetrical
on extensor surfaces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is guttate psoriasis?

A

lots of smaller coin sized plaques instead of few large ones

often after throat infection

17
Q

give 2 histological features of psoriasis

A

elongation/club shaped junction (dermal papillae)

accumulation of neutrophils in corneal layer

18
Q

how do lichenoid disorders develop?

A

damage to basal layer

lymphocytes attack the basal membrane cells when then start dropping into the dermis

19
Q

describe the histological appearance of lichen planus

A

irregular sawtooth acanthosis
formation of cytoid bodies
band-like infiltration of lymphocytes in the upper dermis
orthohyperkeratosis with hypergranulosis

20
Q

name 4 other types of lichenoid disorders

A

discoid lupus
erythema multiforme
toxic epidermal necrolysis
some drug rashes

21
Q

how does lichen planus present?

A
very itchy small papules with flat plaque topped surfaces
buccam striae (white lacey appearance in mouth)
22
Q

what are immunobullous disorders?

A

where an underlying immune disease causes blisters (bullae/vesicles)appear on the skin
pemphigus
pemphigoid
dermatitis herpatiformis

23
Q

what is pemphigus vulgaris?

A

rare autoimmune bullous disease where IgG auto-antibodies are made against desmoglein 3 which is important in maintaining desmosomal attachment between prickle cells

24
Q

how are desmosomes destroyed in pemphigus vulgaris?

A

immune complexes form on cell surfaces (auto IgG etc)

complement activated and proteases released which disrupt desmosomes resulting in acantholysis

25
Q

how does pemphigus vulgaris present? is this the same with all pemphigus?

A

fluid filled blisters which can rupture to form erosions

common on scalp, face, axillae, groin, trunk and mucosa (e.g mouth)

26
Q

what does pemphigus vulgaris look like histologically?

A

basal layer still attached to dermis

destruction between cells of suprabasal epidermis

27
Q

how is pemphigus vulgaris tested for?

A

immunoflouresence

chickenwire pattern as antibodies between squamous epidermal cells light up

28
Q

what are the differences between pemphigus and pemphigoid?

A
pemphigoid = subepidermal blisters with no evidence of acantholysis
pemphigus = epidermal blisters with acantholysis
29
Q

what happens in bullous pemphigoid?

A

IgG antibodies react with a major antigen of hemidesmosomes which anchor basal cells of epidermis to the dermis at the junction
results in complement activation and tissue damage causing the epidermis to detach from the dermis and fluid to build up in between

30
Q

how is bullous pemphigoid tested for?

A

immunoflouresence

IgG deposited around the basal layer

31
Q

what is dermatitis herpatiformis?

A

relatively rare autoimmune bullous disease associated with HLA-DQ2 haplotype and occurs with coeliac disease

32
Q

how does dermatitis herpatiformis present?

A

intensely itchy symmetrical lesions on the elbows, knees and buttocks

33
Q

what is the histological appearance of dermatitis herpatiformis?

A

lots of neutrophils in the upper dermis causing micro abscesses

34
Q

what happens in dermatitis herpatiformis?

A

IgA in dermal papillae target gliadin in gluten but also cross react with connective tissue proteins, activating complement and generating neutrophil chemotaxins

35
Q

how is dermatitis herpatiformis tested for?

A

immunoflouresence shows IgA deposits in dermal papillae

36
Q

how does acne vulgaris develop?

A

increase in androgens at puberty
increased androgen sensitivity of sebaceous glands causes excess sebum production and blockage of pilosebaceous units, this results in inflammation and infection