Eschar is a hard, dry layer of dead tissue over a wound. Along with slough and necrotic tissue, it’s one of the kinds of devitalized tissue that debridement removes — but it is the one that is sometimes deliberately left alone.
Here’s why. Debridement may be contraindicated for dry and intact eschars with no clinical evidence of underlying infection. One example is an unstageable pressure ulcer with an intact eschar at the sacrum, buttock, or heel. In that case the intact eschar serves as a biological covering over the underlying skin defect.
A biological covering. It is doing the job a dressing would otherwise do, and removing it would open the wound underneath.
Both conditions matter, and they go together. Dry and intact. And no clinical evidence of underlying infection. If either one is not true, this is not the situation being described.
There’s a downside to having one. A sore covered in dead skin that is yellow, tan, green, or brown can’t be staged, because the dead skin makes it hard to tell how deep the sore is.
So a wound with intact eschar may be watched rather than treated, and nobody can say how deep it is while the covering is there. That is an uncomfortable position, and it’s worth understanding rather than reading as neglect.
What changes it is any sign that the covering is no longer dry and intact, or that something is happening underneath. That is a clinical judgment made by examination — and you should never try to remove dead tissue yourself.