Pyoderma gangrenosum

Question 1

What is it?

Answer 1

a rare, non-infectious, inflammatory disorder

very painful skin ulcer - mainly lower legs

Question 2

what is usually affected?

Answer 2

lower legs

Question 3

pathophysiology

Answer 3

pyoderma gangrenosum is classified as a neutrophilic dermatosis

neutrophilic dermatoses are skin conditions characterised by dense infiltration of neutrophils in the affected tissue and this is often seen on biopsy

Question 4

causes

Answer 4

idiopathic in 50%
inflammatory bowel disease in 10-15%
ulcerative colitis
Crohn’s
rheumatological
rheumatoid arthritis
SLE
haematological
myeloproliferative disorders
lymphoma
myeloid leukaemias
monoclonal gammopathy (IgA)
granulomatosis with polyangiitis
primary biliary cirrhosis

Question 5

location

Answer 5

typically on the lower limb

soften at the site of a minor injury as in this patient’s case and this is known as pathergy

Question 6

initial features

Answer 6

usually starts quite suddenly

small pustule, red bump or blood-blister

Question 7

later features

Answer 7

the skin then breaks down resulting in an ulcer which is often painful

the edge of the ulcer is often described as purple, violaceous and undermined.

the ulcer itself may be deep and necrotic

Question 8

what systemic features may be accompanied?

Answer 8

fever

myalgia

Question 9

Ix

Answer 9

clinical and histology

Question 10

Mx

Answer 10

oral steroids 1st line

immunosuppressive therapy

surgery needs to be postponed until disease is controlled to prevent spread