Erythema chronicum migrans and its clinical variants: a review

Erythema chronicum migrans (ECM) is the pathognomonic sign of the early stage of Lyme disease, a tick-borne illness caused by pathogenic species of Borrelia, a genus of bacteria of the spirochete phylum. Lyme disease has a broad spectrum of clinical manifestations that can vary in severity and imitate other diseases. ECM consists in a slow enlarging erythema with central clearing. Its recognition allows to state the diagnosis and prescribe the correct therapy and blood tests. But beside the classical manifestation of ECM, some other peculiar variants are possible, such as the vesiculobullous, the purpuric-hemorrhagic, the urticarial, the panniculitis-erysipeloid and the necrotic variant. It is important to know these variants in order to recognize Lyme disease in its early stage, and to avoid sequelae that can involve joints, hearts, central and peripheral nervous system. We present our experience with iconographic examples and check the literature about the possible manifestations of ECM.