Eschar also restricts distribution of systemically administered antibiotics because of its avascularity.
From the en.wikipedia.org
The skin barrier is replaced by eschar.
From the en.wikipedia.org
As a result, applying bloodroot to the skin may destroy tissue and lead to the formation of a large scab, called an eschar.
From the en.wikipedia.org
More examples
A dry scab formed on the skin following a burn or cauterization of the skin
An eschar (and from the Greek word eschara (scab)) is a slough 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, and exposure to cutaneous anthrax. ...
A dry, dark scab or scar, especially as a result of burning
The scab formed when a wound or skin is sealed by the heat of cautery or burning. Also the dark crusted ulcer (tache noire) at the site of the chigger (mite larva) bite in scrub typhus.
A scab or dry crust that results from trauma, such as a chemical or electrical burn, infection, or excoriating skin disease. Blackened/carbonized tissue created by electrosurgical or laser energy.