Which type of discoloration is considered the most permanent?

The type of discoloration considered the most permanent is postmortem extravascular discoloration. This occurs after death due to the breakdown of blood cells and the pooling of blood in the tissues, leading to a change in color that persists. Unlike other forms of discoloration that may resolve or change due to various interventions, this type remains consistent because it results from the physical and chemical changes that occur in the body postmortem.

Antemortem discoloration typically indicates a change in skin color due to physiological factors while the individual is still alive and may not be permanent, as it can fade or be treated. Postmortem lividity, while also a result of blood settling and causing a certain coloration, can change if the position of the body is altered after death. Chemical discoloration arises from the application of substances during embalming, which can be adjusted or reversed with different chemicals.

Therefore, given the nature of postmortem extravascular discoloration stemming from irreversible changes post-death, it stands out as the most permanent form of discoloration.