Erythema Nodosum

Question 1

Erythema nodosum

Answer 1

Where red lumps appear across the patient’s shin

Question 2

Pathophysiology of erythema nodosum

Answer 2

Inflammation of the subcutaneous fat on the shins due to a hypersensitivity reaction

Question 3

Conditions associated with erythema nodosum

Answer 3

Streptococcal throat infections

Gastroenteritis

Mycoplasma pneumoniae

Tuberculosis

Pregnancy

Medications

Chronic diseases:

• Inflammatory bowel disease
• Sarcoidosis
• Lymphoma
• Leukaemia

Question 4

WHich medications are associated with erythema nodosum

Answer 4

Oral contraceptive pill and NSAIDs

Question 5

Presentation of erythema nodosum

Answer 5

Red, inflamed, subcutaneous nodules across both shins.

Nodules are raised and can be painful and tender.

Over time the nodules settle and appears as bruises

Question 6

Investigations for erythema nodosum

Answer 6

FBC - lymphoma/leukaemia

CRP - sarcoidosis/IBD

Throat swab - Streptococcal throat infections

CXR - TB, sarcoidosis, mycoplasma pneumonia

Stool microscopy and culture - gastroenteritis

Faecal calprotectin - IBD

Question 7

Management of erythema nodosum

Answer 7

Treat underlying cause

Supportive treatment

Question 8

When does erythema nodosum typically resolve

Answer 8

6 weeks but can last longer