A 10-year-old boy was brought with complaints of fever for 7 days along with dyspnea on exertion and rashes all over his chest and upper limbs. The child was a known case of rheumatic heart disease with mitral regurgitation. The child had experienced similar rash in a waxing and waning pattern with intermittent pains in bilateral knee joints over the past 6 months. On examination, the child had a serpiginous rash with a raised erythematous rim over torso and upper arms (Fig. 1). ESR was elevated (140 mm/hr). Chest X-ray showed cardiomegaly, and echocardiography revealed severe mitral regurgitation and moderate aortic regurgitation with normal left ventricular function.

Fig. 1 Typical serpiginous pattern of the rash in erythema marginatum.

Erythema marginatum is an evanescent, non-pruritic rash that typically occurs on the trunk and extremities, but usually does not affect the face. Erythema marginatum occurs in patients who have rheumatic fever, and it is one of the major Jones criteria for the diagnosis of rheumatic fever. It occurs in less than 10% of rheumatic fever cases and difficult to detect in dark skinned people.