Solitary erythema migrans in Georgia and South Carolina

Objective: To evaluate the incidence of Borrelia burgdorferi infection in h umans with erythema migrans (EM) in 2 southeastern states. Design: Prospective case series. Setting: Family medicine practice at academic center. Patients: Twenty-three patients with solitary EM lesions meeting Centers fo r Disease Control and Prevention (CDC) criteria for Lyme disease. Interventions: Patients underwent clinical and serologic evaluation for evi dence of B burgdorferi infection. All lesions underwent photography, biopsy , culture and histopathologic and polymerase chain reaction analysis for B burgdorferi infection. Patients were treated with doxycycline hyclate and f ollowed up clinically and serologically. Main Outcome Measures: Disappearance of EM lesions and associated clinical symptoms in response to antibiotic therapy; short-term and follow-up serolo gic assays for diagnostic antibody; growth of spirochetes from tissue biops y specimens in Barbour-Stoenner-Kelly II media; special histopathologic sta ins of tissue for spirochetes; and polymerase chain reaction assays of tiss ue biopsy specimens for established DNA sequences of B burgdorferi. Results: The EM. lesions ranged from 5 to 20 cm (average, 9.6 cm). Five pat ients (22%) had mild systemic symptoms. All lesions and associated symptoms resolved with antibiotic therapy. Overall, 7 patients (30%) had some evide nce of B burgdorferi infection. Cultures from 1 patient (4%) yielded spiroc hetes, characterized as Borrelia garinii, a European strain not known to oc cur in the United States; 3 patients (13%) demonstrated spirochetallike for ms on special histologic stains; 5 patients (22%) had positive polymerase c hain reaction findings with primers for flagellin DNA sequences; and 2 pati ents (9%) were seropositive for B burgdorferi infection using recommended 2 -step CDC methods. No late clinical sequelae were observed after treatment. Conclusions: The EM lesions we observed are consistent with early Lyme dise ase occurring elsewhere, but laboratory confirmation of B burgdorferi infec tion is lacking in at least 16 cases (70%) analyzed using available methods . Genetically variable strains of B burgdorferi, alternative Borrelia speci es, or novel, uncharacterized infectious agents may account for most of the observed EM lesions.