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Erythema nodosum

Last updated: September 9, 2020

Summarytoggle arrow icon

Erythema nodosum (EN) is an inflammation of subcutaneous fat caused by a delayed hypersensitivity reaction. Women in early adulthood are commonly affected. Most cases are idiopathic, but an association with a variety of diseases, including infections and autoimmune disorders (e.g., ulcerative colitis), is possible. The characteristic lesions are painful nodules on the lower legs (particularly shins). EN is a clinical diagnosis. The condition typically heals spontaneously within a few weeks and, therefore, generally requires no more treatment than supportive care (e.g., analgesia).

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Epidemiologytoggle arrow icon

References:[1]

Epidemiological data refers to the US, unless otherwise specified.

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Etiologytoggle arrow icon

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Pathophysiologytoggle arrow icon

References:[2][3]

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Clinical featurestoggle arrow icon

  • Nonspecific symptoms: : fever, arthralgia
  • Painful, subcutaneous nodules on both pretibial (anterior leg) surfaces (less common on other areas of skin)
    1. Firm, erythematous (1st week)
    2. Fluctuant (without suppuration) and bluish (2nd week)
    3. Progressively fades (i.e., yellow or brown hue)

References:[2][3]

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Diagnosistoggle arrow icon

References:[2]

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Treatmenttoggle arrow icon

  • Symptomatic treatment
  • Treat underlying disease
  • In severe or refractory cases: systemic steroids

References:[2]

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Prognosistoggle arrow icon

  • Usually self-limiting (within 2–8 weeks), or resolves earlier with effective treatment of underlying disease
  • Recurrence following discontinued treatment is common

References:[2][4]

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