Clinical and epidemiological findings for patients with erythema migrans. Comparison of cohorts from the years 1993 and 2000.

OBJECTIVES: i) To present clinical and epidemiological findings on adult patients diagnosed with typical erythema migrans (EM) at our institution during the year 2000 and ii) To compare the findings with data obtained by the same approach for an identical group of patients from 1993, with the aim of testing the hypothesis that, because of increased knowledge of Lyme borreliosis in 2000 compared with 1993, patients will visit us earlier and consequently present with smaller skin lesions. PATIENTS AND METHODS: Patients who qualified for inclusion in the study were adults diagnosed with typical EM in 2000 and 1993 at the Lyme borreliosis Outpatients' Clinic, Ljubljana, Slovenia. Epidemiological and clinical data were obtained from a questionnaire.
RESULTS: In 2000, 535 patients had typical EM: 309 (57.8%) females and 226 (42.2%) males, aged 15-80 (median 47) years. Tick bite at the site of later EM was recalled by 311 (58.1%) patients a median of 14 days before the onset of the skin lesion, which was localised on the legs in 55.7% of patients. The median duration of EM prior to examination was 8.5 days, the largest diameter of EM was 12 (4-87) cm, and the average area of involved skin was 75 cm2. Thirty-six of 535 (6.7%) patients had more than one skin lesion (maximum number 21), 281/535 (52.5%) patients reported local symptoms (itching 45.2%, burning 12.9%, and pain 7.1%), and 191/535 (35.7%) reported systemic symptoms (fatigue 17.4%, headache 17.2%, myalgia 12.6%, arthralgia 11.2%, vertigo 3.6%, fever 2.5%, and chills 1.5%). In 1993, 892 patients with typical EM were diagnosed. They had similar characteristics to those in 2000 but were younger (44 versus 47 years; p = 0.025), more often remembered a tick bite (654/892 versus 311/535; p = 0.009), had a smaller diameter (10 versus 12 cm; p < 0.001) and surface area of EM (50.2 versus 75.0 cm2), presented more often with homogeneous skin lesions (378/892 versus 191/535; p = 0.010), and more frequently had some of the associated symptoms including nausea (43/892 versus 12/535; p = 0.021) and malaise (124/892 versus 51/535; p = 0.019).
CONCLUSIONS: The majority of findings for the cohorts of EM patients seen in 1993 and 2000 were comparable but--contrary to expectations--in 2000 the duration of EM prior to attending our clinic was not shorter, and the skin lesions were larger and less often homogeneous. These findings indicate that knowledge of Lyme borreliosis did not increase during the period from 1993 to 2000.