Clinical Features:

• A hypersensitivity reaction pattern that occurs secondary to multiple causes, including gastrointestinal, fungal and other infections; inflammatory bowel disease; sarcoidosis; oral contraceptive pills; malignancy and certain drugs.
• Female predominance with a peak age between 20 and 30 years
• Acute onset of tender bright red nodules, most commonly on the anterior shins, resolving in a few weeks

Histologic Features:

• Septal panniculitis comprised mainly of neutrophils, often with some admixed lymphocytes and eosinophils
• The septa also display some degree of edema and/or hemorrhage.
• The inflammation extends into the adjacent periphery of the fat lobules, but the lobules are otherwise largely unaffected.
• Older lesions show thickening of the septa with a predominantly mononuclear infiltrate progressing to eventual granulomatous inflammation and greater involvement of the lobules.

Cases associated with this book:

Erythema nodosum
Author: Artur Zembowicz M.D. Ph.D.

Conference: DermatopathologyConsultations.com Teaching Collection

Erythema nodosum
Author: Stephen Lyle, M.D., Ph.D.

Conference: DermatopathologyConsultations.com Teaching Collection