Psoriasis

Question 1

What is the genetic factor linked to psoriasis?

Answer 1

HLA - Cw6

Question 2

What are the pathological features in psoriasis?

Answer 2

Increases turnover of keratinocytes in epidermis
Thickened, parakeratotic (no nuclei) stratum corneum
Munro micro abscesses
Absence of granular layer
Expanded stratum spinosum
Large capillary vessels in dermis

Question 3

Give some examples of precipitating factors for a flare up of psoriasis?

Answer 3

Emotional stress
Infection e.g. strep throat --> guttate psoriasis
Drugs
Alcohol, smoking
Trauma --> Koebner phenomenon 
HIV/AIDS
UV radiation (10% worsen, 90% improve)

Question 4

Which drugs might trigger psoriasis?

Answer 4

Beta blockers
Lithium
Antimalarials
Withdrawal of steroids

Question 5

Describe the morphology and distribution of chronic plaque psoriasis?

Answer 5

Erythematous, scaly, raised plaques
On extensor aspects of knees, elbows, sacrum and scalp
Often symmetrical

Question 6

What is the Auspitz sign seen in psoriasis?

Answer 6

removing scale reveals pin-point bleeding

Question 7

What is the Koebner phenomenon?

Answer 7

Development of psoriasis as a site of trauma (2-6 weeks post trauma)

Question 8

What is the treatment for scalp psoriasis?

Answer 8

Olive oil (softens plaques)
Tar shampoo
Tar/salicylic acid ointment

Question 9

How does guttate psoriasis present?

Answer 9

guttate = raindrop appearance
–> multiple small psoriatic lesions on trunk
7-10 days post strep throat

Question 10

What is flexural psoriasis?

Answer 10

Shiny red well-demarcated plaques in groin, axilla or inframammary (under boobs)
Scale not prominent as moist areas

Can be confused with fungal infection or intertrigo

Question 11

What is the treatment for flexural psoriasis?

Answer 11

Mild TCS/antifungal preparation

e.g. Trimovate cream or Canesten HC cream

Question 12

What is palmoplantar psoriasis?

Answer 12

Very painful/disabling psoriasis on palms and soles –> fissures
Very thick hyperkeratosis

Question 13

What is palmoplantar pustulosis?

Answer 13

Not psoriasis, related disorder
Sterile yellow pustules fading to brown macules on palms/soles –> scaling
Strong association with smoking

Question 14

What is erythrodermic psoriasis?

Answer 14

Erythroderma = > 90% of skin surface red

Uncommon complication, usually in patients with known/deteriorating psoriasis

Question 15

What are some causes of erythrodermic psoriasis?

Answer 15

Withdrawal of potent steroids
Drug reactions
UV burns

Question 16

What are the complications of erythrodermic psoriasis?

Answer 16

Hypothermia
Cardiogenic shock
Dehydration
Anaemia
Hypoalbuminaemia

Question 17

What is the treatment for erythrodermic psoriasis?

Answer 17

Fluids
Emollients
Immunosuppressants

Question 18

What is generalised pustular psoriasis and what are the features?

Answer 18

Sterile pustules within areas of psoriasis
Painful, fever, malaise
Hypoalbuminaemia, hypocalcaemia, leukocytosis

Question 19

What are some causes of generalised pustular psoriasis?

Answer 19

Withdrawal of steroids
Infection
Pregnancy
Hypocalcaemia

Question 20

What is the management for generalised pustular psoriasis?

Answer 20

Same as erythrodermic psoriasis

Question 21

What are some of the nail changes seen in psoriasis?

Answer 21

Nail pitting
Onycholysis
Oil drop lesions (orange/brown area)
Subungual hyperkeratosis
Nail deformity

Question 22

What is onycholysis?

Answer 22

Separation of nail from bed - white at tip

Question 23

Which conditions are associated with severe psoriasis?

Answer 23

Higher incidence of obesity, DM, metabolic syndrome, CVD and stroke

Question 24

What are the 3 steps in treatment of psoriasis?

Answer 24

1. topical agents
2. phototherapy
3. oral treatments

Question 25

Which topical therapies are used in psoriasis?

Answer 25

``` Regular emollients Coal tar (effective but messy) Dithranol (burns normal skin and stains clothes) Vitamin D analogues Salicylic acid (removes hyperkeratosis) TCS ```

Question 26

Which topical therapy is first line for mild psoriasis and give an example?

Answer 26

Vitamin D analogues e.g. Calcipotriol (dovonex)

Question 27

How/when should TCSs be used in psoriasis?

Answer 27

Mild TCS can be used, often in combination with dovonex e.g. Dovobet Avoid potent TCS --> risk of rebound flare (erythroderma, pustular psoriasis) Also remember risk of flare if taking oral steroids for another condition

Question 28

What are the options for phototherapy in psoriasis?

Answer 28

UVB 3x per week for 6-8 weeks | PUVA (psoralen + UVA)

Question 29

What are the acute side effects of phototherapy?

Answer 29

Erythema/blistering (sunburn) Photoconjunctivitis Exacerbation of herpes simplex

Question 30

What are the chronic effects of phototherapy?

Answer 30

Photoageing | Photocarcinogenesis

Question 31

What are the systemic treatments available for severe psoriasis?

Answer 31

Methotrexate (good if psoriatic arthritis) Ciclosporin Retinoids Biologics