Psoriasis

Question 1

pathogenesis of psoriasis

Answer 1

hyperproliferation of keratinocytes

- faster epidermal turnover time

Question 2

what drives the inflammation in psoriasis

Answer 2

T cells (TH1 + TH17)
IL-12, IL-17, IL-23

Question 3

Histological features of psoriasis

Answer 3

parakeratotic stratum corneum (contains nuclei- usually none)
absence of granular layer
expanded prickle cell layer

Question 4

trigger for flare ups of psoriasis

Answer 4

stress
alcohol + smoking 
drugs: beta blockers, lithium, anti-malarial, steroid withdrawal
Infection: strep throat
Trauma - koebner phenomenon

Question 5

what is the most common type of psoriasis?

how does it present?

Answer 5

chronic plaque psoriasis

• extensor aspects of knees, elbows, sacrum and scalp
• palpable, raised plaques with surface scale
• usually symmetrical

Question 6

what is auspitz sign

Answer 6

removing scale reveals pin point bleeding

Question 7

what is the koebner phenomenon

Answer 7

psoriasis may develop in sites of trauma 2-6 weeks after trauma sustained

• scratches
• burns
• surgical trauma

Question 8

nail symptoms in psoriasis

Answer 8

pitting - small indentations
onycholysis- plate separation due to subungal hyperkeratosis
oil drop lesions - red/yellow discolouration

Question 9

multiple small psoriatic lesions on trunk 7-10 days following streptococcal sore throat in young patient (15-25 years). Most likely diagnosis?

Answer 9

guttate psoriasis

• self limiting
• can use emollients

Question 10

treatment of scalp psoriasis

Answer 10

Mild: tar based shampoo
Severe: potent steroid, then scale removal agent, then fit D analogue

Question 11

appearance of flexural psoriasis

Answer 11

red, shiny smooth patches - less scaly- in groin/armpits

- can be confused with fungal infection

Question 12

what is palmoplantar psoriasis

Answer 12

very thick hyperkeratosis on palms/soles

painful + disabling

Question 13

treatment of palmoplantar psoriasis

Answer 13

topical tar preparations 
salicylic acid 
topical steroids
phototherapy 
systemic immunosuppressants

Question 14

features of pustular psoriasis

Answer 14

sterile pustules (neutrophils) on skin
painful skin, fever, malaise
hypoalbuminaemia, hypocalcaemia and leucocytosis frequent

Question 15

causes of pustular psoriasis

Answer 15

withdrawal of steroids
pregnancy
lithium
hypocalcaemia

Question 16

what is palmoplantar pustulosis

Answer 16

sterile yellow pustules fading to brown macules on hands/feet
strong association with smoking

Question 17

treatment of pustular psoriasis

Answer 17

emollients
fluid balance
systemic therapy often needed - methotrexate / cyclosporin

Question 18

features of erythrodermic psoriasis

Answer 18

> 90% of skin surface red

- usually in patient with known plaque psoriasis

Question 19

complications of erythrodermic psoriasis

Answer 19

hypovolaemia
hypothermia
cardiogenic shock

Question 20

treatment ladder for psoriasis

Answer 20

1. topical therapy
   - emollients
   - tar preparations
   - vit D analogues
   - salicylic acid
   - dithranol
   - topical seroids
2. photherapy
3. oral treatments

Question 21

emollients used in psoriasis

Answer 21

diprobase
epidermis
E45

Question 22

mechanism of action tar preparations

Answer 22

reduces DNA synthesis and epidermal proliferation

Question 23

what drug is dianthrol

Answer 23

vitamin A analogue - anti-mitotic

• should only be used on stable plaque psoriasis
• stains clothing purple

Question 24

examples of vit D analogues used in treatment of psoriasis

Answer 24

Calcipotriol

Calcitriol

Question 25

first line phototherapy in psoriasis

Answer 25

UVB

- 3x week for 6-8 weeks

Question 26

first line systemic therapy in psoriasis

Answer 26

methotrexate

• oral or IM injection once weekly
• regular monitoring of FBC, U+Es, LFTs

Question 27

what systemic medication can be used in acute severe psoriasis flares

Answer 27

ciclosporin

- side effects include hypertension and renal impairment