A 37 year old woman presents to the ED with a week long history of a tender rash on the lower limbs and feeling non-specifically unwell. There is no history of trauma.
- What is the most likely diagnosis?
- What features in the clinical history and image point towards this?
- What diagnoses are associated with this condition?
- What investigation and treatment is required in ED?
Reveal the ICE answer
This patient has erythema nodosum. The pointers in this case include the duration, the fact that it is tender and that the distribution is on the lower limbs (especially anterior tibial) – looking like fading bruises
Erythema nodosum is a panniculitis most probably due to antigen/antibody deposition in the subcutaneous and deep dermal tissues. Though many cases are “idiopathic” it is often associated with underlying conditions such as:
- Bacterial infections – streptococcal, TB, yersinia
- Other infections – chlamydia, hepatitis B
- Inflammatory bowel disease – Crohn’s and ulcerative colitis
- Drugs – sulphonamides, oral contraceptive
- Malignancies – lymphoma, leukaemia
Although the lesions can be biopsied to confirm the diagnosis, ED investigation is largely aimed at detecting serious underlying causes. Investigation should always include a CXR (for sarcoid & TB) and an FBE/ESR (thinking lymphoma & leukaemia). Depending on history and examination, targeted testing for other infections as above may be needed. Symptomatic treatment is with ibuprofen, and in severe cases steroids, with an expectation most cases will resolve over 2-4 weeks.
Ian’s clinical emergencies