erythema nodosum

Question 1

definition of erythema nodosum

Answer 1

panniculitis (inflammation of the subcutaneous fat tissue)

presenting as red or violet subcutaneous nodules

Question 2

aetiology of erythema nodosum

Answer 2

delayed hypersensitivity reaction to antigens associated with various agents, drugs and other diseases

infection

systemic disease

malignancy

drugs

pregnancy

25% of cases have no underlying cause identified

Question 3

infection that can cause erythema nodosum

Answer 3

bacterial

• streptococcus
• TB
• yersinia
• rickettsia
• chlamydia
• leprosy
• leptospirosis

viral

• EBV

fungal

• histoplasmosis
• blastomycosis
• coccidioidomycosis

protozoal

• toxoplasmosis

Question 4

systemic disease that can cause erythema nodosum

Answer 4

sarcoidosis

IBD

behcet’s disease

Question 5

malignancy that can cause erythema nodosum

Answer 5

leukaemia

Hodgkin’s disease

Question 6

drugs that can cause erythema nodosum

Answer 6

sulphonamides

penicillin

OCP

dapsone

BCG vaccine

Question 7

epidemiology of erythema nodosum

Answer 7

young adults

female more

Question 8

sx of erythema nodosum

Answer 8

tender red or violet nodules develop bilaterally on the skins and occaisionally on the thighs and forearms

fatigue,

fever,

anorexia,

weight loss

arthralgia

symptoms of underlying cause

Question 9

signs of erythema nodosum

Answer 9

crops of red or violet dome-shaped nodules on both shins (occasionally involving thighs or forearms) - tender to palpation

low grade pyrexia

joints may be tender and painful on movement

signs of underlying path

Question 10

Ix for erythema nodosum

Answer 10

to determine the underlying pathology

• blood
  
  • anti-streptolysin-O titre at dx and 2-4weeks later to assess for antecedent streptococcal infection
  • FBC
  • UE
  • CRP ESR
  • LFT
  • serum ACE - high in sarcoidosis
• ​throat swab and culture
• mantoux/Heaf skin testing - for TB
• CXR
  
  • hilar lymphadenopathy
  • evidence of sacroidosis, TB and fungal infections