Case definitions for European
Lyme disease have been published. However, multiple erythema migrans may pose a diagnostic challenge. Therefore, we retrospectively reviewed the clinical and serological findings and response to therapy in a cohort of consecutive 54 patients with PCR-confirmed erythema migrans, referred to a university dermatology clinic. The proportion of patients with multiple erythema migrans lesions (usually 2 or 3) was almost equal (46%) to the proportion of patients with single erythema migrans lesions (54%). All patients, except for 2 multiple erythema migrans patients with a concomitant autoimmune
disease, completely responded to treatment. In conclusion, multiple erythema migrans may be more common than anticipated, and since only 50% of the patients were seropositive when seeking medi-cal help, PCR testing of skin lesions is helpful to confirm the diagnosis in clinically atypical cases.