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DefinitionErythema nodosum is an inflammatory disorder. It involves tender, red bumps (nodules) under the skin. CausesIn about half of cases, the exact cause of erythema nodosum is unknown. The remaining cases are associated with an infection or other systemic disorder. Some of the more common infections associated with the disorder are:
Erythema nodosum may occur with sensitivity to certain medicines, including:
Sometimes, erythema nodosum may occur during pregnancy. Other disorders linked to this condition include leukemia, lymphoma, sarcoidosis, rheumatic fever, Behcet disease, and ulcerative colitis. The condition is more common in women than it is in men. SymptomsErythema nodosum is most common on the front of the shins. It may also occur on other areas of the body such as buttocks, calves, ankles, thighs, and arms. The lesions begin as flat, firm, hot, red, painful lumps that are about 1 inch (2.5 centimeters) across. Within a few days, they may become purplish in color. Over several weeks, the lumps fade to a brownish, flat patch. Other symptoms may include:
Exams and TestsYour health care provider can diagnose this condition by looking at your skin. Tests that may be done include:
TreatmentThe underlying infection, drug, or disease should be identified and treated. Treatment may include:
Outlook (Prognosis)Erythema nodosum is uncomfortable, but not dangerous in most cases. Symptoms most often go away within about 6 weeks, but may return. When to Contact a Medical ProfessionalContact your provider if you develop symptoms of erythema nodosum. ReferencesJames WD, Elston DM, Treat JR, Rosenbach MA. Diseases of the subcutaneous fat. In: James WD, Elston DM, Treat JR, Rosenbach MA, Neuhaus IM, eds. Andrews' Diseases of the Skin: Clinical Dermatology. 13th ed. Philadelphia, PA: Elsevier; 2020:chap 23. Korsten P, Sweiss NJ, Baughman RP. Sarcoidosis. In: Firestein GS, Budd RC, Gabriel SE, Koretzky GA, McInnes IB, O'Dell JR, eds. Firestein & Kelley's Textbook of Rheumatology. 11th ed. Philadelphia, PA: Elsevier; 2021:chap 124. Moon M, Guerrero AM, Li X, Koch E, Gehris RP. Dermatology. In: Zitelli BJ, McIntire SC, Nowalk AJ, Garrison J, eds. Zitelli and Davis' Atlas of Pediatric Diagnosis. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 8. Shields BE, Forrestel A, Rosenbach M. Erythema nodosum. In: Lebwohl MG, Heymann WR, Coulson IH, Murrell DF, eds. Treatment of Skin Disease: Comprehensive Therapeutic Strategies. 6th ed. Philadelphia, PA: Elsevier; 2022:chap 76. Zamore R, Bewtra M, Ogdie A. Inflammatory bowel disease-associated arthritis and other enteropathic arthropathies. In: Firestein GS, Budd RC, Gabriel SE, Koretzky GA, McInnes IB, O'Dell JR, eds. Firestein & Kelley's Textbook of Rheumatology. 11th ed. Philadelphia, PA: Elsevier; 2021:chap 83. | |
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Review Date: 7/1/2023 Reviewed By: Ramin Fathi, MD, FAAD, Director, Phoenix Surgical Dermatology Group, Phoenix, AZ. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. No warranty of any kind, either expressed or implied, is made as to the accuracy, reliability, timeliness, or correctness of any translations made by a third-party service of the information provided herein into any other language. © 1997- A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited. | |