Psoriasis

Question 1

What is psoriasis?

Answer 1

Chronic immune mediated disease
Sharply demarcated erythematous plaques with micaceous scale
M=F, 20-30 and 50-60 yrs

Question 2

How is psoriasis a systemic disease?

Answer 2

5-30% develop psoriatic arthritis
Psychological implications
Metabolic syndrome

Question 3

Describe the pathogenesis of psoriasis

Answer 3

Polygenic predisposition and environmental triggers
35-90% have FH
HLA-Cw6 (chromosome 6)
Psoriasis susceptibility regions - PSORS1-9
Infections, drugs, trauma and sunlight

Question 4

Describe the pathophysiology of psoriasis

Answer 4

Adaptive immune system - T cells
Stressed keratinocytes
Activation of dermal dendritic cells (dDCs)
dDCs - lymph nodes, present uncertain antigen to naïve T cells
Differentiation into Th1, 17 and 22
This causes psoriasis dermis and plaque formation as more keratinocytes produced

Question 5

What do interleukins and TNF alpha do?

Answer 5

Amplify inflammatory cascade stimulate keratinocyte proliferation
VEGF - angiogenesis
Neutrophils in acute, active and pustular disease
Cell cycle reduced from 28 days to 3-5

Question 6

Describe the histology of psoriasis

Answer 6

Hyperkeratosis - thickening of stratum corneum
Neutrophils in stratum corneum
Psoriasiform hyperplasia - acanthosis (thickening of squamous cell layer) with elongated rete ridges
Dilated dermal capillaries and T cell infiltration

Question 7

What is included in the examination of a patients skin with psoriasis?

Answer 7

Distribution
Sharply demarcated erythematous papulo-squamous plaques
Pink or purple in light skin and dark down in dark skin
Numerous small and widely disseminated papules and plaques
Erythroderma (red man syndrome) and pustules

Question 8

What is looked at when examining patient?

Answer 8

Skin, nails, scalp and Koebner phenomenon

Question 9

Describe chronic plaque psoriasis

Answer 9

Symmetrical and extensor surfaces
Scaly plaques on elbows and/ or knees
Thick scale and large salmon coloured

Question 10

Describe Guttate psoriasis

Answer 10

Children and adolescents
Can be triggered from viral or bacterial infection - check ASO titre (for strep.)
Acute onset generalised rash - 205mm pink papules with fine scale
Worse on trunk and proximal extremities

Question 11

What are the results of Guttate psoriasis?

Answer 11

May resolve or may trigger chronic psoriasis in susceptible patients

Question 12

Describe palmo-plantar psoriasis or pustulosis

Answer 12

Rash on hands and feet - thick, red and scaly with yellowish brown lesions at edges
Smoking is RF
Sterile inflammatory bone lesions

Question 13

Describe the presentation of scalp psoriasis

Answer 13

Severe dandruff, pink hyperkeratotic plaques at her scalp extending to hairline, neck and forehead
Can also have nail psoriasis
Can lead to alopecia at affected areas

Question 14

Describe flexural/ inverse psoriasis

Answer 14

Less scale
Bilateral axillary rash, shiny pink to red sharply demarcated plaques with no scale
Can be triggered or superinfected by localised dermatophyte candida or bacterial infection

Question 15

Describe pustular psoriasis

Answer 15

Acute onset of generalised red, tender patches
Multiple yellow pustules are seen - sterile
Sometime systemic symptoms
Can overlap with AGEP - acute generalised erythematous pustulosis

Question 16

What are some risk factors for pustular psoriasis?

Answer 16

Pregnancy, rapid taper/ stop of steroids, hyperglycaemia and infection

Question 17

Describe erythrodermic psoriasis

Answer 17

Red man syndrome - More than 80% of body surface is involved
History of stable chronic plaque psoriasis
Shivery and generally unwell
Erythematous with fine scale
Pyrexia and low blood pressure

Question 18

How is psoriasis diagnosed?

Answer 18

Clinical and skin biopsy if atypical

Question 19

What are some differential diagnosis for psoriasis?

Answer 19

Seborrhoeic dermatitis
Lichen planus - sexual forms
Mycosis fungoides
Bowen’s disease, drug eruption, infection, secondary syphilis, contact dermatitis and extramammary pagets

Question 20

How is psoriasis managed in primary care?

Answer 20

Emollients - creams and ointments
Soap substitutes
Vitamin D3 analogues
Coal Tar creams
Topical steroids - use with care. Flexures and genitalia
Salicylic acid

Question 21

What is the mechanism of vitamin D3 analogues?

Answer 21

Inhibit epidermal proliferation

Question 22

What is the treatment used in secondary care for psoriasis?

Answer 22

Optimise topical therapy
Crude coal tar
Dithranol - can burn and not used regularly
UVB phototherapy
Oral retinoids - Acitrectin and Teratogenic

Question 23

What immunosuppression is used for psoriasis?

Answer 23

Methotrexate - can treat psoriasis arthritis and max improvement is 8-12 weeks
Ciclosporin - fast acting but can cause renal side effects and carcinogenicity

Question 24

What small molecule is used for treatment of psoriasis?

Answer 24

Otezla - supresses immune system

Question 25

What biologic therapies are used in treatment of psoriasis?

Answer 25

Anti-TNF - etanercept, infliximab, adalimumab and certolizumab
IL-12,23 - Ustekinumab
IL-17 - secukinumab
IL-23 - tildrakizumab
Patient can form antibodies so may need to switch biologic

Question 26

What is used for monitoring progress in psoriasis?

Answer 26

Psoriasis area severity index (PASI) - surface area, plaque colour, thickness and scale
Dermatology Life Quality Index (DLQI)

Question 27

What is the treatment for erythrodermic psoriasis?

Answer 27

Recognition, admit, fluid balance, bloods/ IV access and thick greasy ointment emollients

Question 28

What is psoriasis associated with?

Answer 28

CVD, smoking, alcohol, metabolic syndrome, depression, suicide, potential harmful light and drug therapies and risks of long term immunosuppression