Psoriasis

Psoriasis is a chronic, inflammatory skin disease characterised by keratinocyte hyperproliferation. The most common type is plaque psoriasis, which causes erythematous raised plaques on extensor surfaces.

Suggested approach to psoriasis OSCE station

Examine

• Dermatological skin exam
  • Skin
  • Scalp 
  • Ears 
• Nails
• Hand joints

Describing lesions

• Plaques
  • ‘There are multiple well-demarcated, raised erythematous plaques over the extensor surfaces.’
  • ‘These range in size from 1-6cm.’
  • ‘There is scaling across the surface of these lesions, but no other secondary features.’
  • ‘These lesions are consistent with chronic plaque type psoriasis.’
• Nails
  • ‘There is also evidence of pitting, subungual hyperkeratosis, onycholysis and Beau lines on the finger nails.’
  • ‘These are characteristic psoriatic nail changes.’
• Joints
  • ‘I can also see a symmetrical polyarthropathy of the distal inter-phalangeal joints with active synovitis.’
  • ‘This could be evidence of psoriatic arthritis.’

Differential diagnosis

• Other types of psoriasis
• Eczema

Types of psoriasis

Chronic plaque	Most common and described here
Guttate	Raindrop lesions
Seborrhoeic	Lesions around nose and ears
Flexural	Flexural surfaces affected
Pustular	Pustular lesions on palms/soles
Erythrodermic	>90% of skin affected

Management

• Avoid precipitants
• Emollients
• Topical treatments
  • Combination treatments (e.g. Dovobet ointment or Enstilar foam) often used first line
  • Vitamin D analogues, e.g. calcipotriol
  • Topical corticosteroids
  • Coal tar
  • Dithranol
  • Topical retinoids
• Phototherapy
• Systemic rheumatological drugs (methotrexate, ciclosporin, infliximab)

Questions

OSCE stations

1. Dermatological skin exam
2. Psoriasis skin exam
3. Psoriasis history
4. More here