Clinical data on symptomatic cutaneous reinfections due to Borrelia burgdorferi sensu lato in Slovenia.

backgroundSymptomatic reinfections with Borrelia burgdorferi sensu lato occur, but their clinical and microbiologic characteristics are insufficiently defined. It, therefore, remains unclear whether having had a primary infection influences the presentation or course of reinfection.

methodsWe compared the clinical and microbiologic findings in patients with primary infection versus reinfection, with each episode presenting with erythema migrans (EM). The analysis included a cohort of patients diagnosed with EM between 1990 and 2014 at an outpatient clinic in Slovenia.

resultsA total of 11,169 patients with EM were included, comprising 635 reinfections and 10,534 primary infections. Patients with reinfection were older (56 vs 48 years; p < 0.001), less frequently had multiple EM lesions (4.4% vs 7.3%; p = 0.022), and less often reported local symptoms at the EM site (42.5% vs 53.6%; p < 0.001). Reinfected patients were less often Borrelia IgM seropositive (35.0% vs 43.6%; p = 0.028) and more often IgG seropositive (63.0% vs 52.8%; p = 0.011). The rate of Borrelia isolation from EM skin lesions, however, was similar in both groups (53%). Reinfections were more frequent in immunocompromised than in immunocompetent patients (6.8% vs 2.4%; p < 0.001).

conclusionsCompared with primary infection, EM due to reinfection shows distinct clinical and serologic features and is less often disseminated. The increased frequency of reinfection among immunocompromised patients supports a role of host immunity in protection against Borrelia reinfection.

trial registrationNCT06835075.