Erythema Nodosum

Question 1

Define:

Answer 1

Panniculitis (inflammation of the subcutaneous fat) that appears as red or violet subcutaneous nodules on bilateral shins

Question 2

Infectious causes:

Answer 2

Bacterial - Streptococcus (most common cause)
Mycobacterium - TB or leprosy 
Viral - EBV 
Fungal - histoplasmosis 
Yersinia

Question 3

Malignancy causes:

Answer 3

Leukaemia

Hodgkin’s

Question 4

Systemic disease causes:

Answer 4

IBD
Sarcoidosis (good prognosis where lupus pernio is poor)
Behcet’s

Question 5

Drug causes:

Answer 5

Sulphonamides 
Penicillin 
OCP
Dapsone 
BCG vaccine 
Pregnancy

Question 6

Aetiology:

Answer 6

Delayed hypersensitivity.

30-50% are idiopathic

Question 7

Epidemiology:

Answer 7

Common in young adults

3x more common in females

Question 8

Symptoms:

Answer 8

Tender violet or red nodules bilaterally on both shins (can be on forearms or thighs but rare)

Weight loss

Fatigue

Fever

Anorexia

Arthalagia

Symptoms of cause

Question 9

Signs:

Answer 9

Crops of violet or red nodules bilaterally on both shins (can be on forearms or thighs but rare)

Tender to touch

Low grade pyrexia

Painful on movement

Signs of the cause

Question 10

Investigations:

Answer 10

To identify the cause

Anti- streptolysin-O titres (to if it is streptococcus)

Bloods - FBC/ESR/CRP - to see if it is an infection or inflammation

Throat swabs + cultures

Mantoux skin test - TB

CXR - to check if TB, sarcoidosis or fungal