erythema nodosum

erythema no·do·sum -nō-'dō-səm n a skin condition characterized by small tender reddened nodules under the skin (as over the shin bones) often accompanied by fever and transitory arthritic pains and commonly considered a manifestation of hypersensitivity

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a type of predominantly septal panniculitis usually occurring as a hypersensitivity reaction to any of numerous provoking agents, including infections (especially beta-hemolytic streptococcal infections and tuberculosis); drugs (especially oral contraceptives and sulfonamides); sarcoidosis; and certain enteropathies. It may also be idiopathic. It most often affects young women, with transient, inflammatory, nonulcerating nodules that are tender, multiple, and bilateral, usually on the shins. Lesions involute slowly, leaving bruiselike patches without scarring. The acute disease is often associated with mild constitutional symptoms such as fever, malaise, and arthralgias. A chronic variant sometimes occurs without serious associated systemic disease. See also e. nodosum migrans.