Wednesday, 22 September 2010

MRCP revision battle 18.2: Psoriasis

Psoriasis is an autoimmune disease that classically causes a silver-scale topped rash on the skin.

It affects 1-2% of the population.

The cause is believed to be abnormal activity of the type 1 T helper cells.
It is associated wtih HLA CW6, B13, B17 and B27.

Females tend to be affected at a younger age than males.

The main 'types' of psoriasis are:
  1. chronic plaque
  2. generalised pustular
  3. palmo-plantar pustulosis
    • strong association with smoking
    • tends to affect middle-aged females
  4. guttate
    • usually young adults/teenagers
    • is often preceded by a strep infection 2-4 weeks before
    • resolves spontaneously in 2-3 weeks
  5. nail
  6. flexural

Athropathy is a feature in 8% and may be in the form of :
  • symmetric arthritis - appears rheumatoid-like; 50%
  • asymmetric arthrtitis - 35% - dactylitis
  • arthritis mutilans - <5%
  • spondylitis
  • distal interphalangeal predominant

Psoriasis can be worsened by multiple factors, including:
  • trauma
  • infection
  • post-partum
  • beta blockers
  • lithium
  • stress
  • alcohol
  • NSAIDs

Management for skin psoriasis is by a host of lotions and potions - coal tar, dithranol, topical vitamin D.... if these haven't already been drummed into you a brief visit to the BAD website (british association of dermatologists, trying to sound cool) to recap might be a good idea.

Now for a brief skirmish with Beau's lines