CRP and syphilis: At the visit before diagnosis, a median (IQR) of 59 (49–66) days prior, 6 patients had an elevated CRP (defined by a value >2 mg/L), including 3 with a current symptomatic sexually transmitted infection (STI; 1 with gonorrhea, 1 with gonorrhea and chlamydia, and 1 with chlamydia and syphilis).