Psoriasis

Question 1

Describe the appearance of Psoriasis in english?

Answer 1

Raised red clean-edged lesions with a sparkly scale.

Question 2

How does psoriasis affect the nails?

Answer 2

Psoriasis of the nails presents with:

• Onycholysis
• Pitting
• Oil spots

Question 3

Describe how Psoriasis biopsies appear histologically?

Answer 3

• Hyperkeratosis (Thickened stratum corneum)
• Munro’s Microabscesses (Neutrophils in S. Corneum)
• Psoriasiform Hyperplasia (Thick squamous cell layer, aka Acanthosis)
• Dilated dermal capillaries
• T cell infiltration

Question 4

Whats the DDX for Psoriasis?

Answer 4

Seborrhoeic Dermatitis
Lichen Planus
Mycosis Fungoides

Question 5

Describe the aetiology of Psoriasis?

Answer 5

A mixture of genetic susceptibility and an environmental trigger

Question 6

What genes determine Psoriasis susceptibility?

Answer 6

PSORS1-9 genes

Question 7

What are the main environmental triggers for Psoriasis?

Answer 7

Infection
Drugs
Trauma
Sunlight

Question 8

Age of onset is determined by a seperate gene?

Answer 8

HLA-Cw6

Question 9

When do most people develop Psoriasis?

Answer 9

Peaks at 20-30 and 50-60

But 75% occur before reaching 40

Question 10

What are the parts of Psoriasis’ pathogenesis?

Answer 10

T cells infiltrate epidermis- lead to inflammation. Increased production of TH1 cytokines esp TNF alpha.TNF-alpha linked to increased keratinocyte proliferation and flare ups.
In dermis- inflammation causes the blood vessels to dilate (vasodilation) at the border between the dermis and the epidermis= ERYTHEMA
Increased release of VEGF- vascular endothelial growth factor leads to angiogenesis
Vasodilation causes neutrophils to accumulate in the stratum corneum.
It also causes keratinocytes to proliferate and accumulate in the stratum Basale. ( cell proliferation increases from 28 days to 3-5)
THIS thins out the stratum Basale but thickens the stratum corneum as the rate at which the keratinocytes are being produced in greater than the rate at which they are being sloughed off.
-Increased cell turnover= plaques and scales

Question 11

How do stressed keratinocytes leads to Th cell activation and what is the consequence?

Answer 11

Keratinocytes activate Dermal Dendritic Cells (dDC)
dDCs trigger lymph nodes to present uncertain antigen to naive T cells
T cells differentiate to Th1, 17 & 22

Th cells cause the plaque formation

Question 12

How is keratinocyte proliferation stimulated?

Answer 12

Interleukins and Anti-TNFalpha amplify the inflammatory cascade

Question 13

What are the systemic signs of Psoriasis?

Answer 13

Psoriatic Arthritis
Psychosocial problems
Metabolic syndrome

Question 14

How is Psoriasis diagnosed?

Answer 14

CLinically

But if atypical take a biopsy and diagnose histologically

Question 15

How would you treat Psoriasis?

Answer 15

Emollients: creams or ointments -
Vitamin D3 analogues (Calcipotriol) +/- top steroids: inhibits epithelial proliferation
Tar creams
Topical steroids
Salicylic acid- removes plaques 
Dithranol
Anthralin- slows down division of cells

Question 16

How do Vit D3 analogues help Psoriasis?

Answer 16

They inhibit epidermal proliferation

Question 17

What are the systemic treatments for Psoriasis?

Answer 17

Retinoids

Immunosuppression

Biologics

Question 18

Describe retinoid use in Psoriasis?

Answer 18

E.g. Acitretin

You must monitor LFTs, lipids and educate that they’re teratogenic for up to 3 yrs post treatment

Question 19

Describe immunosuppresion use in Psoriasis?

Answer 19

Cyclosporin

Methotrexate

Question 20

How do we monitor patients with Psoriasis?

Answer 20

Psoriasis Area Severity Index (PASI)

Dermatology Life Quality Index (DLQI)

Question 21

List some variations of Psoriasis?

Answer 21

• Chronic plaque psoriasis
• Guttate Psoriasis
• Palmo-plantar Psoriasis
• Scalp Psoriasis
• Nail Psoriasis
• Flexure or Inverse Psoriasis
• Pustular Psoriasis
• Erythrodermic Psoriasis

Question 22

How does chronic plaque Psoriasis tend to present?

Answer 22

Large symmetrical plaques on the extensor surfaces

Particularly the backs of elbows/arms

Question 23

How does guttate Psoriasis occur/present?

Answer 23

In kids/adolescents following a viral/bacterial infection
Has lots of pinks spots
Usually self-limiting
Can be treated with phototherapy
It may develop into chronic plaque Psoriasis

Question 24

How does Palmo-plantar Psoriasis occur/present?

Answer 24

Rash on hands and feet

Thick, scaley

Red, yellow, brown lesions

Question 25

Why is scalp Psoriasis important?

Answer 25

It can often be missed in examination

And it can lead to alopecia

Question 26

How is flexural or inverse Psoriasis different?

Answer 26

shiny pink red/ no scales

Question 27

How does pustular Psoriasis occur/present?

Answer 27

Tiny sterile pustules in the plaques

IT occurs when:

• Pregant
• Hypocalcaemic
• Infected
• On rapid steroid withdrawel

Question 28

Whats particularly bad about Erythrodermic Psoriasis

Answer 28

Presents with fever
Covers 90% of skin
Rapid onset generalised erythema and lesions (>80% of body) +/- pustule clusters

Question 29

How do you manage Erythrodermic Psoriasis?

Answer 29

• Bloods (including excluding infection) [Elevated WCC]
• IV access
• Admit to hospital
• Thick/greasy emollient
• Fluid balance!!!
• Find the trigger
• Avoid steroids
• Systemic or Biologic therapy

Question 30

How does salycyclic acid help with treatment?

Answer 30

Removes plaques

Question 31

How does Anthralin help with treatment?

Answer 31

Slows down division of cells

Question 32

Prognosis

Answer 32

• Exacerbations/ remissions
• Progression to arthiritis in 5-10%
• Potential risk of reduced life expectancy
• Associated with the CVS, alcohol, smoking, depression, suicide , melanoma/ non-melanoma skin cancers, lymphoma