摘要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, inflamma-tory 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 ery-thema 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.