Rashes

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

Question 3

What is acanthosis?

Answer 3

Increased thickness of epithelium

Question 4

What is papillomatosis?

Answer 4

Irregular epithelial thickening

Question 5

What is spongiosis?

Answer 5

Oedema fluid between squames appears to increase prominence of intercellular prickles

Question 6

What are the four main reaction patterns and what is an example of each?

Answer 6

Spongiotic-intraepidermal oedema
-Eczema
Psoriadiform 
-Elongation of the rete ridges
-Psoriases
Lichenoid-basal layer damage
-Lichen planus
Vesicobullous blistering
-Pemphigoid

Question 7

What is psoriasis?

Answer 7

Common chronic inflammatory dermatosis

Increased epidermal hyperplasia

Question 8

What is the koebner phenomenon and what exhibits it?

Answer 8

New lesions arising from sites of trauma

Psoriasis

Question 9

What are lichenoid disorders?

Answer 9

Conditions characterised by damage to the basal epidermis

Question 10

What does lichem planus look like?

Answer 10

Itchy flat-topped violaceous papules

Question 11

What is the histology of lichen planus?

Answer 11

Irregular sawtooth acanthosis
Hypergranulosis and orthohyperkeratosis
Band-like upper dermal infiltrate of lymphocytes
Basal damage with formation of cytoid bodies

Question 12

What is the primary feature of immunobullous disorders?

Answer 12

Blisters

Question 13

What is pemphigus?

Answer 13

Rare autoimmune bullous disease with loss of epidermal cell adhesion integrity

Question 14

Can pemphigus be fatal?

Answer 14

Yes

Question 15

Does pemphigus respond to treatment?

Answer 15

Yes, Steroids

Question 16

What is the most common subtype of Pemphigus?

Answer 16

Pemphigus vulgaris

Question 17

Is Pemphigus vulgaris autoimmune?

Answer 17

Yes

Question 18

What are the IgG auto-antibodies against in Pemphigus vulgaris?

Answer 18

Desmoglein 3 (maintains desmosomal attachments)

Question 19

What is the pathogenesis of Pemphigus vulgaris?

Answer 19

Immune complexes form on cell surface
Complement activation and protease release
Disruption of desmosomes
End result is acantholysis
Produces fluid filled blisters which rupture to form shallow eroisions

Question 20

What is acantholysis?

Answer 20

Lysis of intercellular adhesion sites

Question 21

What is the characteristic of bullous pemphigoid?

Answer 21

Subepidermal blister

Question 22

Is there acantholysis in bullous pemphigoid?

Answer 22

No

Question 23

What is the pathogenesis of bullous pemphigoid?

Answer 23

Circulating antibodies IgG react with a major and/or minor antigen of the hemidesmosomes anchoring basal cells to the basement membrance
This results in local complement activation and tissue damage

Question 24

What does immunoflouresence show in bullous pemphigoid?

Answer 24

Linear IgG and complement depositied around the BM

Older lesions show re-epithelialisation of their floor mimicking pemphigus vulgaris

Question 25

What is dermatitis herpetiformis strongly associated with?

Answer 25

Coeliac disease

Question 26

What haplotype is associated with dermatitis herpetiformis?

Answer 26

HLA-DQ2

Question 27

What are the symptoms of dermatitis herpetiformis?

Answer 27

Intensely itchy symmetrical lesions affecting the elbows, knees and buttocks

Question 28

What is the hallmark of dermatitis herpetiformis?

Answer 28

Papillary dermal microabscesses

Question 29

What does immunoflourescence show in dermatitis herpetiformis?

Answer 29

IgA deposits in dermal papillae

Question 30

What is the pathogenesis of dermatitis herpetiformis?

Answer 30

IgA antibodies target gliadin component of gluten but cross react with connective tissue matrix proteins Immune complexes form in the dermal papillae and activate complement and generate neutrophil chemotaxins

Question 31

Is Acne vulgaris common?

Answer 31

Very

Question 32

Where does acne affect?

Answer 32

Sebaceous gland sites Face Upper back Anterior chest

Question 33

What is the pathogenesis of acne?

Answer 33

Increased androgens at puberty Increased androgen sensitivity of sebaceous glands keratin plugging of pilosebaceous units Infection with anaerobic bacterium corynebacterium acnes

Question 34

Which gender is more commonly affected with rosacea?

Answer 34

Females

Question 35

What are the signs of rosacea ?

Answer 35

``` Pustules Recurrent facial flushing Visible blood vessels Vascular ectasia Thickening of skin - Rhinophyma patchy inflammation with plasma cells Perifollicular granulomas Follicular demodex mites ```

Question 36

What can trigger rosacea?

Answer 36

sunlight Alcohol Spicy food Stress

Question 37

What drugs do some rosacea cases respond to?

Answer 37

Tetracyclines