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Psoriasis M009

Last amended 
11 January 2021

In this section

Current RMA Instruments
Reasonable Hypothesis SOP
13 of 2021
Balance of Probabilities SOP
14 of 2021
Changes from previous Instruments

SOP Bulletin 218

ICD Coding
  • ICD-9-CM Codes: 696.1, 694.3, 696.8
  • ICD-10-AM Codes: L40.0, L40.1, L40.2, L40.4, L40.8
Brief description

This skin disorder can affect any part of the body.  It is characterised by increased growth of skin, producing plaques of silvery scale covering sharply demarcated areas of red skin.  The appearance is significantly different when the disease affects the skin creases, genitals, palms of the hands and soles of the feet.

The basis of this disease is immune dysfunction associated with chronic inflammation. This disease chiefly affects the skin but can also affect the joints and eyes (blepharitis, conjunctivitis, corneal lesions and uveitis).  If joint involvement (psoriatic arthritis) is present it is considered using a separate RMA SOP.  Similarly, for the associated eye problems, there are relevant separate RMA instruments.

Confirming the diagnosis

The diagnosis is generally made on clinical grounds, based on the history and physical examination.  A skin biopsy may be necessary in some cases. 

The relevant medical specialist is a dermatologist.

Additional diagnoses covered by SOP
  • Acrodermatitis continua  – Psoriasis affecting the fingers and toes alone.
  • Erythrodermic psoriasis  – complication of unstable or worsening psoriasis. It is a generalised redness and scaling of the skin and can be life threatening.
  • Flexural psoriasis
  • Guttate psoriasis
  • Impetigo herpetiformis (also known as generalised pustular psoriasis).
  • Inverse psoriasis
  • Nummular psoriasis
  • Plaque psoriasis
  • Psoriasis vulgaris
  • Psoriatic nails – Note that less than 5% have psoriasis of the nails as the only manifestation of the condition.
  • Pustular psoriasis
Conditions not covered by SOP
  • Blepharitis* (psoriatic)
  • Conjunctivitis* (psoriatic)
  • Parapsoriasis#
  • Psoriatic arthropathy*
  • Pustulosis palmaris et plantaris#
  • Sebopsoriasis (overlap condition). In this case both psoriasis and seborrhoeic dermatitis* can be determined.

* another SOP applies

non-SOP condition

Clinical onset

Psoriasis can take a variety of clinical forms and can appear at different skin sites at different times.  Clinical onset will be the first manifestation of psoriasis (usually the characteristic rash) at any site.  Later development of psoriasis at different sites or in different forms can be considered as possible clinical worsening of psoriasis.

Clinical worsening

Psoriasis is normally a chronic condition with unpredictable remissions and relapses or unpredictable exacerbations.  A consideration of whether there has been clinical worsening beyond the normal course of the disease will generally require specialist medical opinion.