Psoriasis

Question 1

What is psoriasis?

Answer 1

• Chronic autoimmune inflammatory skin disease
  
  • Due to hyperproliferation of keratinocytes
  • Inflammatory cell infiltration
• Causes:
  
  • Patches of silvery scales
  • Itchy/sore red flaky area of skin

Question 2

Name three types of psoriasis

Answer 2

• Chronic plaque psoriasis (80-90%)
• Guttate: raindrop lesions
• Seborrhoeic
• Flexural
• Pustular: palmar-plantar
• Erythrodermic: whole body

Question 3

What are the characteristic features of skin lesions in psoriasis?

Answer 3

• Epidermal hyperproliferation
• Abnormal keratinocyte differentiation
• Lymphocyte inflammatory infiltrate

Question 4

Name two conditions that may be associated with psoriasis

Answer 4

• Psoriatic arthritis
• Metabolic syndrome; ischaemic heart disease
• IBD: particularly Crohn’s disease
• Anxiety; depression
• VTE
• Non-melanoma skin cancer

Question 5

Give four presenting features of psoriatic arthritis

Answer 5

• Seronegative inflammatory arthritis
  
  • Affecting up to 30% of people with psoriasis
  • Typical time lag of 5-10 years
• One of the following presentations:
  
  • Symmetrical rheumatoid-like polyarthritis (30-40%)
  • Mono- or oligoarthritis: hands and feet
  • DIPJ involvement: characteristic dactylitis
  • Spondylitis
  • Arthritis mutilans
• Enthesitis; night-time pain in axial skeleton
• Nail changes (90%)

Question 6

Name four triggers for onset or exacerbation of psoriasis

Answer 6

• Streptococcal infection: esp guttate psoriasis
• Drugs ^eg. lithium; NSAIDs; ACEi; penicillin
• Trauma: ‘Koebner phenomenon’
• UV light exposure
• Psychological stress
• Excessive alcohol
• Smoking
• Hormonal: puberty; post-partum; menopause

Question 7

What is the Koebner phenomenon?

Answer 7

Trauma to uninvolved skin followed by psoriasis 7-14 days later

Question 8

Give four presenting features of psoriasis

Answer 8

• Well-demarcated erythematous scaly plaques
  
  • May be itchy; burning; painful
• Extensor surfaces of the body; over scalp
• Auspitz sign
• Nail changes: pitting; discolouration; onycholysis; dystrophy
• Psoriatic arhtritis

Question 9

What is Auspitz sign?

Answer 9

Scratching/removal of psoriatic scales causes capillary bleeding

Question 10

Outline the management of psoriasis

Answer 10

• Avoid precipitating factors; emollients reduce scaling
• Topical therapies: localised and mild psoriasis
  
  • Vitamin D
  • Corticosteroids
  • Coal tar; retinoids; keratolytics; scalp preparations
• Phototherapy: extensive psoriasis
• Oral therapies: extensive and severe psoriasis; systemic
  
  • MTX
  • Retinoids
  • Ciclosporin

Question 11

List three x-ray features of psoriatic arthritis

Answer 11

• Asymmetrical or symmetrical DIPJ involvement
• ‘Pencil in cup’ osteolysis
• Proliferative erosions

Question 12

How is psoriatic arthritis managed?

Answer 12

• Physiotherapy
• Short term steroids or NSAIDs
• DMARDs
• Biologics: infliximab, adalimumab, etanercept
• Dermatology referral