Psoriasis

Question 1

What causes the development of psoriasis?

Answer 1

Polygenic predisposition and environmental triggers

Family history is very common

Question 2

What HLA is associated with psoriasis?

Answer 2

HLA-Cw6 (Chromosome 6)

Question 3

What are examples of environmental triggers?

Answer 3

Infection

Drugs

Trauma

Sunlight

Question 4

What is the involvement of the immune system in psoriasis?

Answer 4

Stressed keratinocytes - activation of dermal dendritic cells

These dermal dendritic cells travel to the lymph nodes and present antigen to niave T cells

T cells differentiate into Th 1, 17 and 22

Leads to psoriatic dermis and plaque formation

Keratinocyte proliferation because interleukins and TNF alpha amplify inflammatory cascade

VEGF causes angiogenesis

Neutrophils in acute, active, pustular phase

The cell cycle is reduced from 28 days to 3-5 days

Question 5

What is the histology of psoriasis?

Answer 5

• 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 6

Describe the skin in psoriasis

Answer 6

–Sharply demarcated, erythematous, papulosquamous plaques

–Numerous small, widely disseminated papules & plaques

Pustules

Erythroderma

Question 7

Describe the nails in psoriasis

Answer 7

–Onycholysis, pitting, oil spots

Onchylosis: is a common medical condition characterized by the painless detachment of the nail from the nail bed, usually starting at the tip and/or sides.

Question 8

What is chronic plaque psoriasis?

Answer 8

Chronic

Salmon coloured plaques

Found on extensor surfaces and is extensive

Question 9

What is Guttate psoriasis?

Answer 9

Acute onset generalised rash

Papules

Affects children and adolescents

Papules worse on trunk and proximal extremities

Check ASO titre

Can be triggered by viral or bacterial infections

It may resolve or it may even trigger chronic psoriasis

Question 10

What form of psoriasis is associated with skin on the palms and soles appears thick, scaly and red with yellowish brown lesions at the edges?

Answer 10

Palmo-plantar Psoriasis

Question 11

What type of psoriasis is associated with severe dandruff - pink hyperkeratotic plaques at her scalp

Answer 11

Scalp psoriasis

Question 12

What type of psoriasis causes pitting in the nails?

Answer 12

Nail psoriasis

Question 13

What type of psoriasis is likely to occur bilaterally in the axilla?

With NO scale

Answer 13

Flexural / inverse psoriasis

Question 14

What can trigger or even superinfect flexural psoriasis?

Answer 14

Can be triggered or superinfected by localised dermatophyte, candidal or bacterial infection – these are also differential diagnoses

Question 15

What type of psoriasis has generalised red tender patches with multiple yellow pustules?

Answer 15

Pustular psoriasis

Pustules are sterile - sometimes features systemic symptoms

Question 16

What causes pustular psoriasis?

Answer 16

Pregnancy

Rapid taper / stoppping steroids

Hypocalcaemia

Infection

Question 17

Erythrodemic psoriasis is often a complication of psoriasis - what is the differential?

Answer 17

Red man syndrome - drug reaction to vancomycin

Question 18

What is the diagnosis of psoriasis?

Answer 18

Skin biopsy

Question 19

What are the differential diagnosis’ for psoriasis?

Answer 19

• Seborrhoeic dermatitis
• Lichen planus
• Mycosis fungoides

Question 20

What is the treatment of psoriasis?

Answer 20

Most treated in primary care - less than 30 % are referred to dermatology

Emollients (creams vs ointments)

Soap substitutes

Vitamin D3 anologues - these inhibit epidermal proliferation

Coal tar creams

Topical steroid

Salycilic acid (keratolytic) - this is a descaling agent

Question 21

What are the available treatments in dermatology?

Answer 21

• Crude Coal Tar (inpatient or day treatment)
• Dithranol: since 1916. Can burn.
• UVB Phototherapy (not the same as sunbed)

–Guttate

Question 22

What systemic disease is associated with psoriasis?

Answer 22

–5-30% develop psoriatic arthritis

–Psychosocial implications

–Metabolic syndrome – more susceptible to having cardiovscular complications

Question 23

What are the systemic treatments of psoriasis?

Answer 23

•Retinoid - Acitretin

–Teratogenic, LFTs, lipids

•Immunosuppression

–Methotrexate

• Can treat PsArthritis
• Max improvement 8-12 weeks

–Ciclosporin

•Renal, cancer risk

•Biologic Therapies

–Qualifying criteria, cost

–Anti-TNF: Etanercept, infliximab, adalimumab

–IL-12,23: Ustekinumab

–Patient can form antibodies to biologic

Question 24

Future treatments

Answer 24

• Targeted biologics
• IL-17,20,22
• Kinase inhibitors
• Ethical / cost dilemmas

–Adalimumab ~£9000 per year (£225000 for 25 years)

–Methotrexate ~£12.50 per year

Question 25

What is the treatment of Erythrodermic Psoriasis?

Answer 25

• Admit
• FLUID BALANCE
• Bloods / IV access
• Thick greasy ointment emollients
• ?Systemic or biologic treatment
• ?Trigger

Question 26

What can be used to monitor the progress of psoriasis?

Answer 26

•Psoriasis Area Severity Index (PASI)

–Surface area, plaque colour, thickness, scale

•Dermatology Life Quality Index (DLQI)

–QOL in last 1 week