Eschar

An eschar (/ˈɛskɑːr/; Greek: ἐσχάρᾱ, romanized: eskhara; Latin: eschara) is a slough[1] or piece of dead tissue that is cast off from the surface of the skin, particularly after a burn injury, but also seen in gangrene, ulcer, fungal infections, necrotizing spider bite wounds, tick bites associated with spotted fevers and exposure to cutaneous anthrax.

A newly identified human rickettsial infection, R. parkeri rickettsiosis, can be differentiated from Rocky Mountain spotted fever by the presence of an eschar at the site of inoculation.

Eschar may be allowed to slough off naturally, or it may require surgical removal (debridement) to prevent infection, especially in immunocompromised patients (e.g. if a skin graft is to be conducted).

An escharotic is a substance that kills unwanted or diseased tissue, usually skin or superficial growths like warts, leaving them to slough off.

For lack of anything better in the past, escharotics once were more widely used, and for example, popular products included so-called black salves, with ingredients such as zinc chloride, plus sanguinarine in the form of bloodroot extract.