Erythema Nodosum Flashcards
Define Erythema Nodosum (+ what type of reaction is it)
Cutaneous hypersensitivity reaction consisting of erythematous, tender nodules due to panniculitis (inflammation of the subcutaneous fat tissue)
Type IV hypersensitivity (delayed)
Aetiology of Erythema Nodosum
Idiopathic (60%)
Pregnancy
Bacterial: Streptococcal, TB | Leprosy | Brucellosis, Yersinia | Mycoplasma P
Fungal: Coccidiomycosis | histoplasmosis | blastomycosis | Dermatophytosis
Viral and chlamydial: Psittacosis | infectious mononucleosis | Hep B
Drugs e.g. sulfonamides, oral contraceptives, bromides and iodides
Malignancy: lymphoma, leukaemia, paraneoplastic
Behçets disease
IBD
Sarcoidosis
Whipple’s disease
Epidemiology of Erythema Nodosum
Peak 20-30
Women affected more frequently than men, especially in the childbearing years
Associated with pregnancy and lactation
Tuberculosis: tropical countries Behçets disease: Turkey and Mediterranean xoast Fungal: US Brucellosis: Dairy workers and farmers Psittacosis: exposure to birds
Symptoms of Erythema Nodosum
Nodules
- Found on the shins most commonly, also found on thighs and forearms
- Bilateral
- Red or violet
- Does NOT tend to ulcerate or scar
Red eyes
Fatigue, fever, anorexia, weight loss
Joint pain (arthralgia)
Generalised with erythema and swelling
Symptoms of cause
Signs of Erythema Nodosum on examination
Nodules
- Bilateral on shins or other areas (thighs, forearms)
- Tender to palpation
- Red or violet
Low-grade pyrexia
Joints tender and painful on movement
Investigations for Erythema Nodosum
Clinical diagnosis on exam + find the cause
Skin testing: positive for causative organism (fungal)
FBC: WCC raised
Anti-streptolysin-O (ASO) titre: Group A beta heamolytic strep. detection
Serum ACE: ?sarcoidosis
CXR: bilateral hilar adenopathy (sarcoidosis) | Unilateral hilar adenopathy (tuberculosis, histoplasmosis, coccidioidomycosis, and brucellosis)
