Pathology of the Skin

Question 1

What is hyperkeratosis?

Answer 1

Increased thickness of keratin layer

Question 2

What is parakeratosis?

Answer 2

persistence of nuclei in the keratin layer (pre-malignant or inflam)

Question 3

What is acanthosis?

Answer 3

Increased thickness of epithelium

Question 4

What is Papillomatosis?

Answer 4

Irregular epithelial thickening

Question 5

Spongiosis?

Answer 5

oedema fluid between cells

Question 6

What are the 4 classifications of inflam skin diseases?

Answer 6

spongiotic
psoriasiform
lichenoid-basal layer damage
vesiculobullous- blistering

Question 7

What is the aetiology of acne?

Answer 7

Increased androgens at puberty
increased androgen sensitivity of sebaceous glands
keratin plugging of pilosebaceous units - then rupture
infection with anaerobic bacterium

Question 8

What is the bacteria that infects pilosebaceous units in acne vulgaris?

Answer 8

corynebacterium acnes

Question 9

What is a comedone?

Answer 9

Follicules impacted and distended by incompletely desquamated keratinocytes and sebum

Question 10

What is a blackhead?

Answer 10

open comedone

Question 11

What is a whitehead?

Answer 11

closed comedone

Question 12

Is Rosacea more common in females or males?

Answer 12

Females

Question 13

Give the clinical features of rosacea

Answer 13

recurrent facial flushing (erythema)
scaling
visible blood vessels 
small pustules 
thickening of the skin (rhinophyma)

Question 14

What can trigger/aggravate rosacea?

Answer 14

sunlight
alcohol
spicy foods
stress

Question 15

What is the pathology of rosacea?

Answer 15

Vascular ectasia
Patchy inflammation with plasma cells
Pustules
Perifollicular granulomas
Follicular Demodex mites often noted (possibe allergic reaction to mites)

Question 16

What are the primary features of immunobullous disorders?

Answer 16

blisters

Question 17

What is pemphigus?

Answer 17

Loss of integrity of epidermal cell adhesion

Question 18

What does pemphigus respond to?

Answer 18

steriods

Question 19

Which subtype of pemphigus make sup 80% of cases of pemphigus?

Answer 19

Pemphigus vulgaris

Question 20

Describe what happens in pemphigus vulgaris?

Answer 20

Desmoglein 3 maintains desmosomal attachments
Immune complexes form on cell surface
Complement activation and protease release
Disruption of desmosomes
End result is ACANTHOLYSIS – epithelium dissolves
Intraepidermal bulla

Question 21

What are the auto-antibodies in pemphigus vulgaris directed against?

Answer 21

desmoglein 3

Question 22

Where does pemphigus vulgaris affect?

Answer 22

skin esp. scalp, face, axillae, groin, trunk

Question 23

Where can pemphigus vulgaris affect? Not usually.

Answer 23

Mucoa - mouth and respiratory tract

Extensive mucosal involvement may be fatal

Question 24

What is common to all variants of pemphigus?

Answer 24

the process of acantholysis = lysis of intercellular adhesion sites

Question 25

How dos pemphigus vulgaris present?

Answer 25

Produces fluid filled blisters which rupture to form shallow erosions

Question 26

On fluorescent staining of the skin with pemphigus vulgaris, what is it said to resemble?

Answer 26

chicken wire

Question 27

What is bullous pemphigoid?

Answer 27

Subepidermal blister with no evidence of acantholysis

Question 28

What do the auto-antibodes in bullous pemphigoid react with?

Answer 28

Circulating antibodies (IgG) react with a major and/or minor antigen of the hemidesmosomes anchoring basal cells to basement membrane. The result is local complement activation and tissue damage

Question 29

How would you describe bullous pemphigoid?

Answer 29

discrete fluid filled blisters due to breaking of the DEJ

Question 30

What is the hallmark of dermatitis herpetiformis?

Answer 30

papillary dermal microabscess

Question 31

where and how does dermatitis herpetiformis present?

Answer 31

Symmetrical intensely itchy lesions on the elbows, knees and buttocks (often excoriated)

Question 32

What is dermatitis herpetiformis associated with?

Answer 32

coeliac disease and HLA-DQ2 haplotype

Question 33

Explain the autoimmunity aspect of dermatitis herpetiformis.

Answer 33

- 90% with DH have gluten sensitive enteropathy (may be asymptomatic) - DIF shows deposits of IgA in dermal papillae - IgA antibodies target gliadin component of gluten but cross react with connective tissue matrix proteins - Immune complexes form in dermal papillae and activate complement and generate neutrophil chemotaxins.