From the Guidelines
Erythema nodosum should be treated based on the underlying cause, with systemic corticosteroids required in severe cases and immunomodulators or anti-TNF for relapsing and resistant forms. The diagnosis of erythema nodosum is made on clinical grounds, and in atypical cases, a skin biopsy might be helpful 1. Treatment is usually based on that of the underlying inflammatory bowel disease (IBD). Key considerations in managing erythema nodosum include:
- Identifying and addressing the underlying cause, such as IBD, infections, or medications
- Using systemic corticosteroids in severe cases, as recommended by the European evidence-based consensus on extra-intestinal manifestations in inflammatory bowel disease 1
- Considering immunomodulators or anti-TNF for relapsing and resistant forms of erythema nodosum, as suggested by the same consensus 1
- Providing symptom relief through rest, leg elevation, and non-steroidal anti-inflammatory drugs (NSAIDs) if necessary. The most recent and highest quality study on this topic is from 2016, published in the Journal of Crohn's and Colitis 1, which provides guidance on the diagnosis and treatment of erythema nodosum in the context of IBD.
From the Research
Definition and Characteristics of Erythema Nodosum
- Erythema nodosum is the most frequent clinico-pathological variant of the panniculitides, characterized by inflammatory, tender, nodular lesions, usually located on the anterior aspects of the lower extremities 2.
- The disorder is a cutaneous reaction consisting of painful, erythematous, subcutaneous nodules mainly localized to the pretibial areas, often bilateral and symmetrical, ranging from 1 to 5 cm in diameter 3.
- The typical eruption consists of a sudden onset of symmetrical, tender, erythematous, warm nodules and raised plaques usually located on the shins, ankles, and knees, which may become livid red or purplish and finally exhibit a yellow or greenish appearance 2.
Associated Conditions and Causes
- Erythema nodosum may be associated with a wide variety of diseases, including infections, sarcoidosis, rheumatologic diseases, inflammatory bowel diseases, medications, autoimmune disorders, pregnancy, and malignancies 2.
- The most common identifiable causes are streptococcal infections, primary tuberculosis, sarcoidosis, Behçet disease, inflammatory bowel disease, drugs, and pregnancy 4.
- In approximately 50% of cases, the condition is idiopathic 3.
Diagnosis and Diagnostic Algorithm
- The diagnosis is mainly clinical, with biopsy reserved for atypical cases 3.
- A diagnostic algorithm can be used to optimize the initial work-up, including an initial assessment of core symptoms, diagnostic work-up, differential diagnosis, and recommended therapies 4.
- Laboratory and instrumental examinations, such as complete blood cell count, erythrocyte sedimentation rate, and/or C-reactive protein, throat swab culture, antistreptococcal O titers, and a chest radiograph, may be performed to identify any underlying trigger disease 5, 3.
Treatment and Management
- Treatment of erythema nodosum should be directed to the underlying associated condition, if identified 2.
- Most cases of erythema nodosum are self-limited and require no treatment, with bed rest and leg elevation recommended to reduce discomfort 3.
- Nonsteroidal anti-inflammatory drugs (NSAIDs) are the first-line treatment for pain management, and other options, such as potassium iodide and colchicine, may be used 2, 6.
- Systemic corticosteroids are rarely indicated in erythema nodosum and should be used with caution, as they may be contraindicated in certain underlying conditions, such as infections 2, 5.