Erythrema Nodosum

Question 1

Define Erythema Nodosum

Answer 1

Common cutaneous hypersensitivity reaction with erythematous tender nodules-most commonly on shins, thighs, buttocks

will fade in time into pigmented area

usually a result of immune triggers and infections

Question 2

Aetiology and risk factors of Erythema Nodosum

Answer 2

Streptococcus is one of the most common causes, along with IBD
Sarcoidosis
Tuberculosis and beret disease can also cause it-esp in less developped world
Histoplasmosis/coccimycosis-fungal-also a cause, esp in rural US

No cause found in 60%

Risk factors
Women 20-30's
Streptococcus infection prior
IBD
Sarcoidosis
Tuberculosis
Fungal infections
Oral contraceptives

Question 3

Epidemology of Erythema Nodosum

Answer 3

More frequent in Europe and USA
peak 20 to30

women 6x >men
mainly depends on incidence of causative disease

Question 4

Signs and Sx of Erythema Nodosum

Answer 4

Want to take good Hx-esp what happened before/any associated Sx
main goal is identifying aetiology

Lesions are red, tender, Non ulcerated, immobile patches on the shins
-resolves within 8 weeks
can be other places but rare

Joint pain and swelling can present along side-
Examinations are normal if idiopathic

But can have signs of infections (lungs-TB, strep)
Or IBD (bowels)
Dont ignore rheumathoid causes-sarcoidosis
want to rule out Strep, TB, sarcoidosis

Question 5

Investigations of Erythema Nodosum

Answer 5

Clinical diagnosis is often all thats needed
Biopsy can be used to confirm

Finding cause
FBC/U&E-signs of infection or inflame-usually raised WCC

anti-streptolysin 0-elevated in strep infection

CXR-Unilateral hilar adenopathy–reveal TB or Histoplasmosis/coccidomycosis/brucellosis
bilateral-sarcoidosis

any other Ix for IBD,