Sensitivity of Two-Tiered Lyme Disease Serology in Children With an Erythema Migrans Lesion.

In our prospective cohort of 192 children with a physician-diagnosed erythema migrans (EM) lesion, two-tier Lyme disease serology had higher sensitivity in children with multiple EM lesions (76.8% multiple lesions vs. 38.1% single EM; difference 38.7%, 95% confidence interval 24.8%-50.4%). The diagnosis of cutaneous Lyme disease should be based on careful physical examination rather than laboratory testing.