Erythema Nodosum, Idiopathic

Erythema nodosum (EN) is a skin condition in which red bumps (nodules) form on the shins. Less commonly, the nodules form on other areas of the body such as the thighs and forearms. The lesions begin as firm, hot, red, painful lumps and progress to a purplish color. EN is a type of inflammatory disorder affecting the layer of fat under the skin (http://dermnetnz.org/dermal-infiltrative/panniculitis.html" target="_blank">panniculitis). Other symptoms that may accompany the skin findings include the following: fever, a general feeling of being ill. joint aches, and swelling of the affected area. In many cases, EN is presumed to be a delayed reaction to https://www.nlm.nih.gov/medlineplus/ency/article/002224.htm" target="_blank">antigens associated with various infections, drugs, and certain systemic diseases. In some cases, however, EN has no identifiable cause (idiopathic); in these cases, clinical follow-up is needed to rule out certain conditions including https://www.nlm.nih.gov/medlineplus/ency/imagepages/19219.htm" target="_blank">inflammatory bowel disease, https://rarediseases.info.nih.gov/gard/7607/sarcoidosis/resources/1" target="_blank">sarcoidosis, https://www.nlm.nih.gov/medlineplus/lymphoma.html" target="_blank">lymphoma, and https://rarediseases.info.nih.gov/gard/848/behcets-disease/resources/1" target="_blank">Behcet's disease. Treatment may include rest, nonsteroidal anti-inflammatory drugs (NSAIDS), steroids, hot or cold compresses, potassium iodide solution, and supportive bandages or https://www.nlm.nih.gov/medlineplus/ency/patientinstructions/000597.htm" target="_blank">compression stockings. Symptoms usually resolve within six weeks, but EN may become a chronic disorder lasting for months and, occasionally, for years. Approximately 30% cases of idiopathic EN may last more than 6 months.