February 2015 | Case of the month - gain CPD points

• The diagnosis was consistent with Pyoderma gangrenosum (PG), a rare, neutrophilic dermatosis, commonly associated with systemic disease
   
• Although there are a number of PG variants, the typical presentation is a painful ulcer (or ulcers) that grows rapidly and develops an irregular, undermined, blue-purple edge
   
• 50-70% of cases have an underlying cause, approximately equally divided between three groups:
  • Inflammatory bowel disease (IBD), especially ulcerative colitis
  • Haematological conditions, especially myeloid leukaemia's. Also myelodysplasia and monoclonal gammopathy
  • Inflammatory arthritis such as rheumatoid arthritis
     
• PG affects males and females equally. It can arise at any age, but is more common over the age of 50. Pain is the predominant complaint and is out of proportion to the clinical findings 
   
• Typical features of PG include:
  • It usually starts quite suddenly, and sometimes at the site of a minor injury
  • Although any body site can be affected, the lower legs are the most common site
  • The initial lesion may be a papule, pustule or bulla, but this soon develops in to an ulcer
  • The ulcer (or ulcers) enlarges rapidly (normally > 1 cm per day), with an irregular, undermined, purple-blue edge
  • Untreated, the ulcer may continue to enlarge, persist unchanged or slowly heal. Deep ulcers heal with scarring, sometimes with a cribriform pattern 
     
• ​Pathergy - patients with PG may demonstrate pathergy, which is an exaggerated skin injury (the development of a papule, pustule or ulcer) within a few days of minor trauma. This can be tested for by using a sterile needle and making pricks in the skin

For more information on Pyoderma gangrenosum and its management please click on the link.