Misdiagnosis of erythema migrans.

BACKGROUND

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.

PATIENTS AND METHODS

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.

RESULTS

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.

CONCLUSIONS

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