Psoriasis ☺️

Question 1

Epidemiology
Genetics and environment
Pathophysiology

Answer 1

2-3% of population affected
Common in white
20s and 60s

HLA B13-17 - P
HLA B27 - PA
Worsened by skin trauma, stress, strep infection
Improved with sunlight

Abnormal T cell activity => overproduction of keratin and angiogenesis

Question 2

Describe the skin presentation of psoriasis

• plaque
• guttate
• flexural
• pustular

Answer 2

Plaque - most common

• demarcated red, scaly silvery patches
• extensors, sacrum, scalp
• pinpoint bleeding when picked

Guttate

• transient psoriatic rash triggered by strep infection 2-4wks before
• red, teardrop lesions on trunk, limbs

Flexural
-smooth skin

Pustular
-palms and sores

Question 3

What are the other associated features

• nails
• joints

Answer 3

Nail pitting, onycholysis
Psoriatic arthritis (dactylitis and enthesitis)
-rheumatoid like polyarthritis
-asymmetrical oligoarthritis
-sacroilitis
-DIP joints
-arthritis mutilans

Associated with other seronegative conditions

Question 4

Complications of psoriasis

Answer 4

Psoriatic arthritis
Increased risk of 
-metabolic syndromes
-CVD, VTE
-psych distress

Question 5

Management

• topical
• specialist
• medical

Answer 5

Topical

• CS
• emollients
• vitamin D analogues
• tar

Specialist
-phototherapy

Systemics

• methotrexate
• ciclosporin
• fumaric acid esters

Biologics

• TNFa
• IL12/23
• IL17
• IL23/p19

Question 6

Investigations

Diagnosis

Answer 6

Xray of hands and feet - coexistance of erosive changes and new bone formation

• periostitis
• pencil in cup

Xray of sacroiliac joints for axial involvement

Diagnosis based on criteria