Psoriasis

Question 1

Who normally gets guttate psoriasis?

Answer 1

Children and adolescents.

Question 2

What normally precedes a guttate psoriasis?

Answer 2

streptococcal infection 2-4 weeks prior to the lesions appearing

(e.g. strep throat)

Question 3

Features of guttate psoriasis

Answer 3

• tear drop papules on the trunk and limbs
• tends to be acute onset over days

Question 4

Management of guttate psoriasis

Answer 4

• most resolve within 2-3 months
• topical agents as per psoriasis
• UVB phototherapy
• tonsillectomy if recurrent strep infections

Question 5

Pathophysiology of psoriasis

Answer 5

Genetic: associated:
HLA-B13, HLA-B17, HLA-Cw6.

Immunological:
abnormal T-cell activity stimulates keratinocyte proliferation

Question 6

What can worsen psoriasis?

Answer 6

• Skin trauma
• stress
• Streptococcal infection
• alcohol
• Drugs: beta blockers, lithium, antimalarials, NSAIDs and ACEi, infliximab
• Withdrawal of systemic steroids

Question 7

Types of psoriasis

Answer 7

plaque psoriasis
- scaly plaques affecting extensor surfaces and scalp

flexural psoriasis
- skin is smooth

guttate psoriasis
- triggered by a streptococcal infection
- red teardrop papules

pustular psoriasis
- on palms and soles

Question 8

Whaat nail signs can be seen in psoriasis

Answer 8

pitting,
onycholysis

Question 9

What is the first line treatment of chronic plaque psoriasis

Answer 9

potent corticosteroid OD + vitamin D analogue OD

one applied in the morning and the other in the evening

for up to 4 weeks

Question 10

If a potent corticosteroid and vitamin D analogue do not work as first line treatment in psoriasis, what can be tried?

Answer 10

second-line: vit D analogue BD

third-line:
- potent corticosteroid BD for up to 4 weeks
- or a coal tar preparation OD/BD

Question 11

What treatments can be offered for psoriasis in Secondary Care?

Answer 11

Phototherapy
- narrowband UVB
- 3 times a week

Photochemotherapy
- psoralen + UVA (PUVA)
S/E: skin ageing, SCC

Systemic therapy:
- MTX
- Ciclosporin
- Systemic retinoids
- Biologics

Question 12

Management of scalp psoriasis

Answer 12

Use topical agent to remove adherent scale (eg. containing salicylic acid/oils

then apply topical potent steroid

Question 13

What is the maximum length of time topical steroids can be used on the face?

Answer 13

2 weeks/ 1 month
high risk of skin atrophy and side effects

Question 14

Systemic side-effects may be seen when potent corticosteroids are used on what percentage of the body area?

Answer 14

> 10% of the body surface area

Question 15

How long should you leave between courses of topical steroids?

Answer 15

4-week break

Question 16

What is the maximum length of time you should be using a potent topical steroid and a VERY potent topical steroid

Answer 16

8 weeks - potent
4 weeks - very potent

Question 17

Mechanism of action of Vitamin D analogues

Answer 17

↓ cell division and differentiation
=> ↓ epidermal proliferation

Question 18

Advantages and disadvantages of vitamin D analogues

Answer 18

ADV:
- adverse effects uncommon
- can be used long-term
- do not smell or stain

DISADV:
- reduce the scale and thickness of plaques but not the erythema
- must be avoided in pregnancy

Question 19

Mechanism of action of dithranol

Answer 19

inhibits DNA synthesis

Question 20

Disadvantages of Dithranol as a psoriasis treatment

Answer 20

• can cause burning, staining
• need to leave on for 30mins before washing off