We report the case of a four-year-old girl who died within hours after she was seen for pain in the knee and varicella. The death was due to fulminant sepsis with group-A Streptococcus. The postmortem examination revealed a bacterial infection of the varicella skin lesions, which resulted in bacteremia leading to generalized sepsis. The pain in the knee was initially thought to be secondary to septic arthritis, varicella arthritis, or osteomyelitis, but it was diagnosed after death as septic popliteal thrombophlebitis associated with fulminant group-A streptococcal septicemia. We report the case of our patient to bring attention to this rare but life-threatening cause of pain in the knee.