Erythema Nodosum

Question 1

Erythema Nodosum

Lesion histology and symptom

Answer 1

acute or chronic inflammation of subcutaneous fat (panniculitis)
• round, red, tender, poorly demarcated nodules

Question 2

Erythema Nodosum sites

Answer 2

asymmetrically arranged on extensor lower legs (typically shins), knees, arms

Question 3

Erythema Nodosum asoc. symptoms

Answer 3

arthralgia, fever, malaise

Question 4

Erythema Nodosum

Etiology

Answer 4

• 40% are idiopathic
• drugs: sulfonamides, OCPs (also pregnancy), analgesics, trans retinoic acid
• infections: GAS, TB, histoplasmosis, Yersinia
• inflammation: sarcoidosis, Crohn’s > UC
• malignancy: acute leukemia, Hodgkin’s lymphoma

Question 5

Erythema Nodosum
Epidemiology.
Duration of the lesion

Answer 5

15-30 yr old, F:M 3:1

• lesions last for days and spontaneously resolve in 6 wk

Question 6

Erythema Nodosum Investigations

Answer 6

CXR (to rule out chest infection and sarcoidosis)

• throat culture, ASO titre, PPD skin test

Question 7

Erythema Nodosum. Management

Answer 7

symptomatic: bed rest, compressive bandages, wet dressings
• NSAIDs, intralesional steroids
• treat underlying cause