Psoriasis

Question 1

What is Psoriasis?

Answer 1

Chronic, immune mediated disease

Sharply demarcated erythematous plaques with micaceous scale

Systemic disease:
5-30% develop psoriatic arthritis
Psychosocial implications
Metabolic syndrome

Question 2

Who does Psoriasis affect?

Answer 2

3% of UK population, M=F
20-30yrs & 50-60yrs.
75% before 40yrs

Question 3

Psoriasis Pathogenesis

Answer 3

Polygenic predisposition + environmental triggers

35-90% have a family history

HLA-Cw6
(Chromosome 6)

Age of onset Psoriasis susceptibility regions 	PSORS1-9

Infection
Drugs
Trauma
Sunlight

Question 4

Psoriasis Genetics

Answer 4

HLA-Cw6
(Chromosome 6)

PSORS1-9

35-90% have a family history

Question 5

Psoriasis Immune Pathology

Answer 5

Adaptive immune system
T cells

Stressed keratinocytes

Activation of dermal dendritic cells (dDCs)
by interleukins:
TNF alpha

dDCs –> lymph nodes, present uncertain antigen to naïve T cells
Differentiation into:
Th (T helper) 1, 17 &22

• -> psoriatic dermis
• -> plaque formation

Question 6

Describe the process of keratinocyte proliferation seen in Psoriasis
* cell cycle length *

Answer 6

Interleukins & TNF alpha amplify inflammatory cascade, stimulate keratinocyte proliferation
VEGF  angiogenesis
Neutrophils in acute, active, pustular disease

** Cell cycle reduced from 28 days to 3-5 **

Question 7

Psoriasis Histology

Answer 7

Hyperkeratosis (thickening of stratum corneum)
Neutrophils in stratum corneum (Munro’s microabcesses)
Psoriasiform hyperplasia: acanthosis (thickening of squamous cell layer) with elongated rete ridges
Dilated dermal capillaries
T cell infiltration

Question 8

Psoriasis Munro’s microabcesses

Answer 8

Neutrophils in stratum corneum

Question 9

Psoriasiform hyperplasia:

Answer 9

acanthosis (thickening of squamous cell layer) with elongated rete ridges

Question 10

Histology of capillaries in Psoriasis:

Answer 10

Dilated

Question 11

Term used to describe - thickening of stratum corneum - in Psoriasis:

Answer 11

Hyperkeratosis

Question 12

O/E Psorosis

Answer 12

Skin
Distribution!
Sharply demarcated, erythematous, papulosquamous plaques
Pink or purple in light skin, dark brown or hyperpigmented in dark skin
Numerous small, widely disseminated papules & plaques
Erythroderma (>80% BSA)
Pustules

Question 13

Subtypes of Psoriasis:

54 year old male presents with a 15 year history of scaly plaques on both elbows. Over the last few months the rash has spread to involve large areas of his body.
He has recently lost his job and has been diagnosed with hypertension.

O/E he has large salmon coloured plaques on his arms, legs and back with thick scale.

Answer 13

Chronic Plaque Psoriasis: symmetric, extensor surfaces

15 YEAR HISTORY

Question 14

Subtypes of Psoriasis:

A 14 year old boy presents with an acute onset of a generalized rash.

O/E he has multiple 2-5 mm pink papules with a fine scale, worse on the trunk and proximal extremities.

His mother says that he had a throat infection 2-3 weeks prior to the rash.

Answer 14

Guttate psoriasis.

Children, adolescents.

Can be triggered by viral or bacterial infections. Check ASO titre.

May resolve, or may trigger chronic psoriasis in susceptible individuals.

Question 15

Subtypes of Psoriasis:

A 32 year old lady presents with several months’ history of a rash on her hands and feet. She works as a beautician / masseuse and wants it to be cured.

O/E the skin on the PALMS and SOLES appears thick, scaly and red with YELLOWIS brown LESIONS at the edges.

Answer 15

Palmo-plantar Psoriasis, or pustulosis.

Studies show that psoriasis of the palms and soles tends to have greater impact on QOL compared to more extensive psoriatic involvement not involving the palms and soles.

Smoking
Sterile inflammatory bone lesions

YELLOW - PUSTULES

Question 16

Subtypes of Psoriasis:

27 year old lady presents to your clinic complaining of severe dandruff. She has tried various shampoos with out much effect. She has noticed that the DANDRUFF is spreading onto her face as well.

O/E you see pink hyperkeratotic plaques at her SCALP, extending just beyond the hairline onto her neck and forehead. She has some pitting at her NAILS.

Answer 16

Scalp Psoriasis
Can lead to alopecia at affected areas

&

Nail Psoriasis
Difficult to treat

Question 17

Subtypes of Psoriasis:

A 36 year old man presents with several months history of a BILATERAL AXILLARY RASH.

He has been treated with topical and oral anti-fungal agents recently without any benefit. Skin scrapings show no growth.

O/E you see shiny pink to red sharply demarcated plaques with NO scale.

Answer 17

Flexural / Inverse PsoriasisLess scaleCan be triggered or superinfected by localised dermatophyte, candidal or bacterial infection – these are also differential diagnoses

Question 18

A 50 year old lady presents with an acute onset of generalised red, tender patches. On closer inspection of the patches multiple yellow pustules are seen.

Answer 18

Pustular Psoriasis

Sterile pustules, sometimes systemic symptoms

Pregnancy, rapid taper/stop steroids, hypocalcaemia, infection

Overlap with AGEP (pustular drug eruption)

Question 19

A 67 year old man arrives with a 35 years history of stable chronic plaque psoriasis.

His wife died 8 weeks ago and his psoriasis started to flare. He was prescribed 2 weeks course of oral Prednisolone, which was stopped without tapering. He presents feeling shivery and generally unwell.

O/E More than 80% of his body surface area is erythematous, with fine scale. He is pyrexial and has a low blood pressure.

Answer 19

Erythrodermic psoriasis

‘Red Man’ syndrome
>80% body surface area involved!!!

Question 20

Diagnostic Investigations - Psoriasis

Answer 20

Clinical

Skin biopsy if atypical

Question 21

Psoriasis other dy/dx

Answer 21

Seborrhoeic dermatitis

Lichen planus

Mycosis fungoides

Bowens disease, drug eruption, infection, secondary syphillis, contact dermatitis, extramammary Pagets…

Question 22

Psoriasis Primary Care

Management/treatment

Answer 22

<30% of patients seen in primary care are referred to dermatology

Emollients
Creams vs Ointments
Soap substitutes

Vitamin D3 analogues: inhibit epidermal proliferation
Coal Tar creams
Topical Steroid – with care.

Flexures, genitalia
Salicylic acid (keratolytic)

Question 23

Psoriasis Secondary Care

Management/treatment

Answer 23

Optimise topical therapy
Crude Coal Tar (inpatient or day treatment)
Dithranol: since 1916. Can burn.

UVB Phototherapy

Oral retinoids
Acitretin
Teratogenic

Question 24

Psoriasis

Immunosuppression, Small Molecules, Biologic Therapies:

Answer 24

Immunosuppression:
Methotrexate
Can treat psoriatic arthritis 
Max improvement 8-12 weeks
Ciclosporin
Fast acting
Renal SEs, carcinogenicity 

Small Molecules:
Otezla (apremilast)

Biologic Therapies:
Qualifying criteria, cost
Anti-TNF: Etanercept, infliximab, adalimumab, certolizumab
IL-12,23: Ustekinumab
IL-17: Secukinumab, brodalumab, ixekizumab
IL-23: tildrakizumab, guselkumab, risankizumab
Patient can form antibodies

Question 25

Psoriasis Monitoring Progress

Answer 25

Psoriasis Area Severity Index (PASI)
Surface area, plaque colour, thickness, scale
Dermatology Life Quality Index (DLQI)
QOL in last 1 week

Question 26

Erythrodermic Psoriasis

Answer 26

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

?Systemic or biologic treatment
?Trigger

Question 27

Key points to consider for Psoriasis

Answer 27

Professionalism
Be interested, examine patients properly

Chronic but treatable
Patient (and physician!) education, compliance

Consider QOL and metabolic factors

Potential for hugely successful, but also expensive, treatments