Role of tetracycline in recalcitrant erythema nodosum

Erythema Nodosum: A Practical Approach and Diagnostic Algorithm

Erythema nodosum is the most common form of panniculitis and is characterized by tender erythematous nodules mainly in the lower limbs on the pretibial area. The exact cause of erythema nodosum is unknown, although it appears to be a hypersensitivity response to a variety of antigenic stimuli. Although the etiology is mostly idiopathic, ruling out an underlying disease is imperative before diagnosing primary erythema nodosum. Erythema nodosum can be the first sign of a systemic disease that is triggered by a large group of processes, such as infections, inflammatory diseases, neoplasia, and/or drugs. The most common identifiable causes are streptococcal infections, primary tuberculosis, sarcoidosis, Behçet disease, inflammatory bowel disease, drugs, and pregnancy. We propose a diagnostic algorithm to optimize the initial work-up, hence initiating prompt and accurate management of the underlying disease. The algorithm includes an initial assessment of core symptoms, diagnostic work-up, differential diagnosis, and recommended therapies. Several treatment options for the erythema nodosum lesions have been previously reported; nevertheless, these options treat the symptoms, but not the triggering cause. Making an accurate diagnosis will allow the physician to treat the underlying cause and determine an optimal therapeutic strategy.

Erythema nodosum

BACKGROUND

Erythema nodosum can be associated with a number of systemic diseases. There is, however, a paucity of information in the pediatric literature on this condition. The purpose of this article is to familiarize pediatricians with the evaluation, diagnosis, and treatment of erythema nodosum.

DATA SOURCES

A PubMed search was completed in Clinical Queries using the key terms "erythema nodosum".

RESULTS

Clinically, erythema nodosum presents with a sudden onset of painful, erythematous, subcutaneous nodules mainly localized to the pretibial areas. Lesions are usually bilateral and symmetrical, ranging from 1 to 5 cm in diameter. Erythema nodosum may be associated with a variety of conditions such as infection, medications, sarcoidosis, pregnancy, inflammatory bowel disease, vaccination, autoimmune disease, malignancy, and miscellaneous causes. The condition is idiopathic in approximately 50% of cases. The diagnosis is mainly clinical with biopsy reserved for atypical cases. To evaluate for the underlying cause, some basic laboratory screening studies are worthwhile in most cases and include a complete blood cell count, erythrocyte sedimentation rate and/or C-reactive protein, throat swab culture, antistreptococcal O titers, and a chest radiograph. Other tests should be individualized, guided by the history and physical examination results. Most cases of erythema nodosum are self-limited and require no treatment. Bed rest and leg elevation are generally recommended to reduce the discomfort. Nonsteroidal anti-inflammatory drugs are the first-line treatment for pain management.

CONCLUSIONS

As erythema nodosum is often a cutaneous manifestation of a systemic disease, a thorough search should be performed to reveal the underlying cause.