Erythema NodosumCase: A pre-teen girl, living in central California, recently started on fluconazole, now presenting with a bilateral leg rash. What is your diagnosis? Click on the image for a larger view.

Poll Results

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Erythema nodosum, secondary to coccidioidomycosis


Erythema nodosum is a cutaneous reaction consisting of inflammatory, tender erythematous subcutaneous nodular lesions. The classically painful rash is located on the lower extremities and usually regresses spontaneously. It is associated with a wide variety of disease processes1,2 including:

  • Most common cause: Streptococcal infections
  • Other causes:
    • Behcet’s syndrome
    • Oral contraceptive use
    • Pregnancy
    • Sarcoidosis
    • Tuberculosis
    • Viral infections

Coccidioidomycosis is endemic to certain arid parts of the Southwest United States. Erythema nodosum is the most characteristic reactive cutaneous manifestation of coccidioidomycosis. It presents 1-3 weeks after onset of illness and is usually self-limited.3 While strep infections are the most common cause of erythema nodosum, in a patient who has recently visited the American southwest, suspect coccidioidomycosis.


Master Clinician Bedside Pearls

Stuart Swadron, MD

Stuart Swadron, MD – Professor of Emergency Medicine, Keck School of Medicine of the University of Southern California (provided to ALiEM and recorded by Swadron, 2014)

Schwartz R, Nervi S. Erythema nodosum: a sign of systemic disease. Am Fam Physician. 2007;75(5):695-700. [PubMed]
Psychos D, Voulgari P, Skopouli F, Drosos A, Moutsopoulos H. Erythema nodosum: the underlying conditions. Clin Rheumatol. 2000;19(3):212-216. [PubMed]
Bettinger C, Zimmermann H. New investigations on hematoxylin, hematein, and hematein-aluminium complexes. I. Spectroscopic and physico-chemical properties of hematoxylin and hematein. Histochemistry. 1991;95(3):279-288. [PubMed]
Jeff Riddell, MD

Jeff Riddell, MD

Assistant Professor of Clinical Emergency Medicine
Co-Director, Medical Education Fellowship
LA County + USC Emergency Medicine Residency, Department of Emergency Medicine
Keck School of Medicine of the University of Southern California