Septicemia is a serious, rapidly progressing, life-threatening infection that can arise secondary to localized infections of the respiratory, genitourinary or gastrointestinal tract, or from the skin. It may precede or coincide with infections of the bone, central nervous system or other tissues; it can rapidly lead to septic shock and death, being associated with organisms such as meningococci that can lead to shock, adrenal collapse and disseminated intravascular coagulation.

Onset of septicemia is heralded by spiking fevers and chills, rapid breathing and heart rate, the outward appearance of being seriously ill (toxic) and a feeling of impending doom. These symptoms rapidly progress to shock with decreased body temperature (hypothermia), falling blood pressure, confusion or other changes in the mental status, and clotting abnormalities evidenced by hemorrhagic lesions in the skin.