From the Guidelines
Erythema nodosum is diagnosed on clinical grounds, and treatment is usually based on that of the underlying condition, with systemic corticosteroids required in severe cases, as stated in the most recent and highest quality study 1. The diagnosis of erythema nodosum is made on clinical grounds, with a skin biopsy being helpful in atypical cases, as supported by multiple studies 1. Key characteristics of erythema nodosum include:
- Tender, red nodules typically appearing on the shins
- Can occur on other areas of the body
- Represents a delayed hypersensitivity reaction where immune complexes deposit in the subcutaneous fat, triggering inflammation Treatment focuses on addressing the underlying cause while managing symptoms, with options including:
- NSAIDs like ibuprofen or naproxen for pain and inflammation
- Bed rest and elevation of the affected limbs to reduce swelling and discomfort
- Potassium iodide solution to help resolve the nodules faster in some cases
- Oral corticosteroids like prednisone for severe or persistent cases
- Colchicine for recurrent cases, as recommended in the management of Behçet disease 1 It is crucial to identify and treat the underlying cause to prevent recurrence and achieve complete resolution, as erythema nodosum can recur and represents a reaction pattern to various triggers, including infections, medications, inflammatory bowel disease, sarcoidosis, or pregnancy.
From the Research
Diagnosis of Erythema Nodosum
- Erythema nodosum is characterized by tender, erythematous, subcutaneous nodules that typically are located symmetrically on the anterior surface of the lower extremities 2, 3, 4, 5, 6
- The disorder is a cutaneous reaction consisting of inflammatory, tender, nodular lesions, usually located on the anterior aspects of the lower extremities 2
- Erythema nodosum does not ulcerate and usually resolves without atrophy or scarring 2, 3, 4, 6
- Histopathologically, erythema nodosum is the stereotypical example of a mostly septal panniculitis with no vasculitis 2, 3
- A deep incisional or excisional biopsy specimen should be obtained for adequate visualization 4
- Diagnostic evaluation after comprehensive history and physical examination includes complete blood count with differential; erythrocyte sedimentation rate, C-reactive protein level, or both; testing for streptococcal infection; and biopsy 4, 5
Treatment of Erythema Nodosum
- Treatment of erythema nodosum should be directed to the underlying associated condition, if identified 2, 3, 5
- Usually, nodules of erythema nodosum regress spontaneously within a few weeks, and bed rest is often sufficient treatment 2, 3
- Aspirin, nonsteroidal anti-inflammatory drugs, such as oxyphenbutazone, indomethacin or naproxen, and potassium iodide may be helpful drugs to enhance analgesia and resolution 2, 3, 6
- Systemic corticosteroids are rarely indicated in erythema nodosum and before these drugs are administered an underlying infection should be ruled out 2, 3, 6
- Pain can be managed with nonsteroidal anti-inflammatory drugs 4
- It is possible to distinguish between an acute and a chronic form of erythema nodosum; in the acute form, an early stage and a late stage can be detected, both clinically and histologically 6