Misdiagnosis of erythema migrans

Erythema migrans is a clinical diagnosis that carries possible long-term repercussions. Despite widespread awareness of the clinical presentation of erythema migrans, incorrect diagnosis occurs.

We describe 13 cases in which erythema migrans was misdiagnosed and discuss some pitfalls in diagnosis. These cases were seen at a tertiary referral center in Connecticut, a state where Lyme disease is endemic. The patients selected for inclusion were those who most clearly illustrate potential difficulties involved in making the diagnosis of erythema migrans.

The diagnosis of erythema migrans was missed in 5 patients due to atypical presentations. Eight patients with skin eruptions closely mimicking erythema migrans were incorrectly diagnosed with erythema migrans.

There are pitfalls associated with the diagnosis of erythema migrans that may result in overdiagnosis or underdiagnosis.