Lecture 6 Psoriasis

Question 1

Define Psoriasis

Answer 1

Chronic, genetically determined, immune-mediated, inflammatory skin condition, usually characterized by typical well defined, scaly, plaques.
Sharply demarcated erythematous plaques with micaceous scale

Question 2

What areas can psoriasis involve

Answer 2

Nails
Hair
Joints

Question 3

What are the clinical features of Psoriasis

Answer 3

• Red scaly plaques
• Symmetrical distribution
• Chronic plaque
• Flexural

Question 4

What is the aetiology of psoriasis

Answer 4

• Overactivity of the immune system
• Excessive production of TH1 Cytokines inc TNF-alpha
• Vascular proliferation (erythema), increased cell turnover (plaques and scaling)
• Genetics
• Environmental
• Infection- Strep, Candida
• Drugs- Lithium, Beta-blockers, NSAIDS, Steroid withdrawal
• Trauma – Koebner phenomenon (spread with trauma)
• Sunlight
– HLA, Cw6, B13, B17- age of onset
– PSORS1-9- susceptibility regions

Question 5

Pathogenesis of Psoriasis

Answer 5

• Epidermal infiltration by activated T cells
– Cell cycle reduced from 28 days to 3-5 days (built up plaques)
– VEGFCapillary angiogenesis
– Activation of dDC by IL and TNF alpha
– Differentiation into Th1, 17, 22

Question 6

What is the histology in psoriasis

Answer 6

Hyperkeratosis
Hypogranulosis
Psoriasiform
Dilated dermal capillaries
Perivascular lymphohistiocytic infiltrate; T cell infiltration

Question 7

How do you assess a patient

Answer 7

• Age & nature of onset
• Distribution- symmetrical/asymmetrical
• Effective or ineffective treatments
• Medical history
• Family history
• Medications
• QOL

Question 8

On examination of the skin what are you looking for

Answer 8

•	Skin
–	Distribution
–	Sharp demarcation
–	Pink/purple/dark brown/ hyperpigmented
–	Papules/macules/plaques
–	Erythroderma
–	Pustules
•	Nails
–	Onycholysis- lifting of nail from nail bed
–	Pitting
–	Oil spots
•	Scalp
–	More plaque like and scaly compared to dandruff
•	Koebner Phenomenon
–	Scars or injuries

Question 9

Subtypes of Psoriasis

Answer 9

Chronic Plaque Psoriasis
Guttate Psoriasis
Palmoplantar Psoriasis 
Scan Psoriasis
Flexural/inverse Psoriasis
Pustular psoriasis
Erythrodermic Psoriasis

Question 10

Management

Answer 10

•	Emollients
–	Creams- daytime
–	Ointments- overnight
•	Soap substitutes 
•	Vitamin D3 analogues (calcipotriol +/- Topical steroids) = inhibits epidermal proliferation
•	Tar creams
•	Topical steroid- flexural/genital
•	Salicylic acid (Keratolytic)- very scaly plaque to get through to root of the psoriasis
•	Crude coal tar
•	Dithranol- can burn
•	Anthralin
•	UVB phototherapy- Guttate
•	Oral retinoids (Vit A)
–	Acitretin
–	Impairment of LFTs/Lipids
–	Teratogenic

Question 11

Name immunosuppression treatments

Answer 11

•	Methotrexate
–	Once a week
–	Psoriatic arthritis
•	Ciclosporin
–	Fast acting
–	Renal SEs, Carcinogen
–	Maximum of year

Question 12

How do you monitor Psoriasis

Answer 12

• PASI- Psoriasis Area Severity Index (objective)
• DLQI- Dermatology Life Quality Index (subjective)
• Bloods- if on systemic treatment

Question 13

How do you manage erythrodermic psoriasis

Answer 13

• Admit
• FLUID BALANCE
• Bloods / IV access
• Thick greasy ointment emollients