# Why Is the Duration of Erythema Migrans at Diagnosis Longer in Patients with Lyme Neuroborreliosis Than in Those without Neurologic Involvement?

## TL;DR

This study finds that the duration of the erythema migrans skin lesion is longer in patients with Lyme neuroborreliosis compared to those without neurological symptoms.

## Contribution

The study confirms that EM duration is longer in LNB patients, regardless of the specific neurological manifestation.

## Key findings

- EM duration in LNB patients was significantly longer than in patients without neurological involvement.
- There was no significant difference in EM duration between different types of LNB.
- Patients with LNB may delay seeking treatment due to unawareness of EM or its importance.

## Abstract

In prior studies, the skin lesion erythema migrans (EM) was present for a longer time period before diagnosis of concomitant borrelial meningoradiculoneuritis (Bannwarth’s syndrome) compared to EM patients without neurologic symptoms. To determine if this observation pertains to other manifestations of Lyme neuroborreliosis (LNB), we compared EM characteristics in patients with borrelial meningoradiculoneuritis (n = 122) to those with aseptic meningitis without radicular pain (n = 72 patients), and to patients with EM but without neurologic involvement (n = 12,384). We also assessed factors that might impact duration. We found that the duration of EM at diagnosis in patients with borrelial meningoradiculoneuritis was not significantly different compared with those with LNB without radicular pain (34 vs. 26 days; p = 0.227). The duration of EM for each of these clinical presentations of LNB, however, was significantly longer than in patients with EM without LNB (10 days; p < 0.001). Contributing factors to this difference might have been that patients with LNB failed to recognize that they had EM or were unaware of the importance of not delaying antibiotic treatment for EM. In conclusion, the duration of the EM skin lesion in EM patients with LNB is longer than in patients with just EM, irrespective of the type of LNB.