Psoriasis

Question 1

What is psoriasis?

Answer 1

Chronic, genetically determined, immune mediated, inflammatory skin condition
Characterised by typical well defined scaly plaques
Can involve nails, hair and joints

Question 2

Epidemiology of psoriasis?

Answer 2

3% of UK population
M=F
Peak incidences 20s, 50s
>1/3 family history (2/3 in presentation before 20yrs)
Systemic disease, link to metabolic syndrome and CVD

Question 3

Different types of psoriasis?

Answer 3

Chronic plaque
Flexural
Acute guttate
Scalp
Palmoplantar
Nail
Pustular
Erythrodermic

Question 4

Causes of psoriasis?

Answer 4

Overactivity of the immune system
Excess production of TH1 cytokines (especially TNF-alpha)
Vascular proliferation and increased cell turnover (from 28 days to 3-5)

Question 5

Environmental risk factors?

Answer 5

Genetics
Infection (Strep, Candida)
Drugs (Lithium, NSAIDS, steroid withdrawal, beta-blockers)
Trauma (Koebner phenomenon - spread with trauma)

Question 6

Histology in psoriasis?

Answer 6

Hyperkeratosis (thickening of stratum corneum)
Neutrophils in stratum corneum
Hypogranulosis
Psoriaform hyperplasia: Acanthosis with elongated rete ridges
Dilated dermal capillaries
T cell infiltration

Question 7

What accounts for 90% of psoriasis?

Answer 7

Chronic plaque psoriasis

Question 8

How is chronic plaque psoriasis commonly managed in the primary care setting?

Answer 8

Topical treatments

Question 9

Guttate psoriasis?

Answer 9

Commonly post-viral
Usually self-limiting
Responds well to phototherapy
May recur

Question 10

Palmoplantar psoriasis?

Answer 10

Greatest impact on patients life

Question 11

Scalp psoriasis?

Answer 11

Could be seborrhoeic dermatitis

Question 12

Nail psoriasis

Answer 12

Pathognomonic features

• Pitting
• Onycholysis

Question 13

Flexural/Inverse psoriasis?

Answer 13

Shiny pink/red sharply demarcated plaque with no scaling

Question 14

Pustular psoriasis?

Answer 14

Acute onset generalised red, tender patches with multiple yellow pustules

Question 15

Erythrodermic psoriasis?

Answer 15

‘Red man’ syndrome
>90% body surface involved
Needs inpatient treatment

Question 16

Differential diagnoses?

Answer 16

Seborrhoeic dermatitis (especially face/scalp)
Lichen planus (check forearm, oral mucosa)
Mycosis fungoides (older patient, sudden onset plaques or resistant to treatment)

Question 17

Initial treatment of psoriasis?

Answer 17

Emollients
Vitamin D3 analogues
Tar creams
Topical steroids
Salicylic acid

Dithranol
Anthralin

Question 18

Second line treatment?

Answer 18

UVB phototherapy
Acitretin (teratogenic)
Methotrexate
Cyclosporine
Inpatient tar (crude coal tar in zinc ointment)
Biologics e.g. Infliximab, adalimumab, ustekinumab