Erythema Nodosum Flashcards
Define erythema nodosum
Panniculitis – inflammation of subcutaneous fat
What are the causes/risk factors of erythema nodosum?
Delayed hypersensitivity reaction to antigens
• Systemic disease e.g. sarcoidosis, IBD, Behçet’s disease
• Infection e.g. Streptococcus, TB, Yersinia, leprosy, EBV, histoplasmosis,
blastomycosis, toxoplasmosis
• Malignancy e.g. leukaemia, Hodgkin’s disease
• Drugs e.g. sulphonamides, penicillin, OCP
• Pregnancy
• Idiopathic
What are the symptoms of erythema nodosum?
- Tender red/violet nodules typically on shins (also thighs, forearms)
- Fatigue
- Fever
- Anorexia
- Weight loss
- Arthralgia
What are the signs of erythema nodosum?
- Tender red/violet dome-shaped nodules
- Low grade pyrexia
- Tender joints, painful on movement
What investigations are carried out for erythema nodosum?
• FBC, ESR, and anti-streptolysin-O (ASO) titres should be assessed on presentation and 2 to 4 weeks later.
• CXR and tuberculin testing are also indicated initially in all patients.
- CXR demonstrates bilateral hilar adenopathy in sarcoidosis; unilateral hilar adenopathy in TB.
• Inflammatory bowel disease may be investigated with endoscopy.
• Serum IgD level is high in Behcet’s disease.
• Serum agglutinins and stool cultures are positive in Yersinia infections.
• Rheumatological causes: This may be further investigated by taking x-rays of affected joints, RF testing, or other testing as indicated by the clinical picture.
• Skin biopsy: Erythema nodosum is primarily a clinical diagnosis, but biopsy may be indicated for atypical lesions, such as those that demonstrate ulceration or that have an atypical distribution.
