Erythema marginatum
Summary
Erythema marginatum is the evanescent, non-pruritic rash of acute rheumatic fever, appearing as pink macules with serpiginous, raised borders and central clearing on the trunk and proximal limbs. It is a major Jones criterion but is uncommon and easily missed.
Detail
The lesions expand outward with a well-demarcated advancing edge while the centre clears, producing annular or polycyclic figures, and they characteristically spare the face. The rash is fleeting, migrating over hours, may be brought out by heat, and is neither itchy nor painful, which distinguishes it from urticaria. It occurs in fewer than ten per cent of cases of acute rheumatic fever, so its absence means nothing, but its presence is highly suggestive. The revised Jones criteria require evidence of preceding group A streptococcal infection plus either two major criteria or one major and two minor; the major criteria are carditis, polyarthritis, chorea, erythema marginatum, and subcutaneous nodules. Erythema marginatum should not be confused with erythema migrans of Lyme disease, which is solitary, larger, slowly expanding over days, and follows a tick bite.
Sources
- First Aid for the USMLE Step 1
- Nelson Textbook of Pediatrics
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