Lyme disease can be classified using the terminology of
syphilis. In this series of 95 cases from the upper midwest, early cases, defined as an illness of less than 2 months, were more likely to have lived in or recently visited a highly endemic area. Unlike late cases, early cases presented entirely in the nonwinter months (p less than .001). Early disease was further subdivided into primary and secondary disease. Ninety percent of primary and 43% of secondary cases had
erythema migrans, while no late cases had active
erythema migrans (p less than .001). Clinical manifestations of nonspecific
inflammation, except for
arthralgia, were more common in early than late disease (p less than .01). In secondary cases, monoarticular
arthritis was slightly more common than polyarticular
arthritis, with the reverse occurring in late disease (p less than .05). Indirect fluorescent antibody testing revealed a ratio of
IgM to
IgG antibodies to be helpful in distinguishing early from late disease. Antibacterial
therapy in early, primary cases caused Jarisch-Herxheimer reaction 7% of the time. Despite longer and more frequent parenteral
therapy, late
Lyme disease frequently required
retreatment, owing to poor clinical response (p less than .05).