Erythema marginatum is a distinctive reactive annular erythema most commonly associated with acute rheumatic fever secondary to streptococcal infection. It is typically found on the trunk and proximal extremities. It usually follows the onset of migratory arthritis, but it may occur months after carditis. Erythema marginatum is typically nonpruritic and overall asymptomatic. Approximately 10% of patients with acute rheumatic fever have the associated rash of erythema marginatum. It is observed more frequently in children than in adults. Erythema marginatum is one of the major Jones criteria, the set of criteria used to diagnose acute rheumatic fever.

Rarer conditions that have been associated with erythema marginatum include psittacosis and C1 esterase inhibitor deficiency (also known as hereditary angioedema). Of note, a case of hemorrhagic erythema marginatum was reported as a cutaneous toxicity to sorafenib in a patient undergoing treatment for hepatocellular carcinoma.