Eschar (; ; ; or ''an'' eschar) is a slough or piece of
dead tissue
Death is the end of life; the Irreversible process, irreversible cessation of all biological process, biological functions that sustain a living organism. Death eventually and inevitably occurs in all organisms. The remains of a former o ...
that is cast off from the surface of the skin, particularly after a
burn injury, but also seen in
gangrene
Gangrene is a type of tissue death caused by a lack of blood supply. Symptoms may include a change in skin color to red or black, numbness, swelling, pain, skin breakdown, and coolness. The feet and hands are most commonly affected. If the ga ...
,
ulcer
An ulcer is a discontinuity or break in a bodily membrane that impedes normal function of the affected organ. According to Robbins's pathology, "ulcer is the breach of the continuity of skin, epithelium or mucous membrane caused by sloughin ...
,
fungal infections
Fungal infection, also known as mycosis, is Infection, a disease caused by pathogenic fungi, fungi. Different types are traditionally divided according to the part of the body affected: superficial, subcutaneous tissue, subcutaneous, and system ...
,
necrotizing spider bite wounds,
tick bites associated with
spotted fever
A spotted fever is a type of tick-borne disease which presents on the skin. They are all caused by bacteria of the genus '' Rickettsia''. Typhus is a group of similar diseases also caused by ''Rickettsia'' bacteria, but spotted fevers and typhus a ...
s and exposure to cutaneous
anthrax
Anthrax is an infection caused by the bacterium '' Bacillus anthracis'' or ''Bacillus cereus'' biovar ''anthracis''. Infection typically occurs by contact with the skin, inhalation, or intestinal absorption. Symptom onset occurs between one ...
. The term ‘eschar’ is not interchangeable with ‘scab’. An eschar contains necrotic tissue whereas a scab is composed of dried blood and
exudate
An exudate is a fluid released by an organism through pores or a wound, a process known as exuding or exudation.
''Exudate'' is derived from ''exude'' 'to ooze' from Latin language, Latin 'to (ooze out) sweat' (' 'out' and ' 'to sweat').
Medi ...
.

Black eschars are most frequently attributed in medicine to cutaneous anthrax (infection by ''
Bacillus anthracis
''Bacillus anthracis'' is a gram-positive and rod-shaped bacterium that causes anthrax, a deadly disease to livestock and, occasionally, to humans. It is the only permanent (obligate) pathogen within the genus ''Bacillus''. Its infection is a ty ...
''), which may be contracted through herd animal exposure and also from ''
Pasteurella multocida'' exposure in cats and rabbits. A newly identified human rickettsial infection, ''R. parkeri''
rickettsiosis, can be differentiated from
Rocky Mountain spotted fever
Rocky Mountain spotted fever (RMSF) is a bacterial disease spread by ticks. It typically begins with a fever and headache, which is followed a few days later with the development of a rash. The rash is generally Petechial rash, made up of small s ...
by the presence of an eschar at the site of inoculation.
[
]
Eschar is sometimes called a ''black wound'' because the wound is covered with thick, dry, black
necrotic tissue.
Eschar may be allowed to slough off naturally, or it may require surgical removal (
debridement
Debridement is the medical removal of dead, damaged, or infected tissue to improve the healing potential of the remaining healthy tissue. Removal may be surgical, mechanical, chemical, autolytic (self-digestion), or by maggot therapy.
In ...
) to prevent infection, especially in immunocompromised patients (e.g. if a
skin graft
Skin grafting, a type of graft (surgery), graft surgery, involves the organ transplant, transplantation of skin without a defined circulation. The transplanted biological tissue, tissue is called a skin graft.
Surgeons may use skin grafting to ...
is to be conducted).
If eschar is on a limb, it is important to assess peripheral pulses of the affected limb to make sure blood and lymphatic circulation is not compromised. If circulation is compromised, an
escharotomy
An escharotomy is a surgical procedure used to treat full-thickness (third-degree) circumferential burns. In full-thickness burns, both the epidermis and the dermis are destroyed along with sensory nerves in the dermis. The tough leathery tissue ...
, or surgical incision through the eschar, may be indicated.
Escharotic
An ''escharotic'' is a substance that kills unwanted or diseased tissue, usually skin or superficial growths like warts, leaving them to
slough
Slough () is a town in Berkshire, England, in the Thames Valley, west of central London and north-east of Reading, at the intersection of the M4, M40 and M25 motorways. It is part of the historic county of Buckinghamshire. In 2021, the ...
off. Examples include:
* inorganic reagents, such as strong acids and alkalis, or
cytotoxic
Cytotoxicity is the quality of being toxic to cells. Examples of toxic agents are toxic metals, toxic chemicals, microbe neurotoxins, radiation particles and even specific neurotransmitters when the system is out of balance. Also some types of dr ...
salts of
heavy metals
upright=1.2, Crystals of lead.html" ;"title="osmium, a heavy metal nearly twice as dense as lead">osmium, a heavy metal nearly twice as dense as lead
Heavy metals is a controversial and ambiguous term for metallic elements with relatively h ...
, for example zinc or silver
* organic compounds such as
sanguinarine
Sanguinarine is a polycyclic quaternary alkaloid. It is extracted from some plants, including the bloodroot plant, from whose scientific name, ''Sanguinaria canadensis,'' its name is derived; the Mexican prickly poppy (''Argemone mexicana''); ''C ...
,
salicylic acid
Salicylic acid is an organic compound with the formula HOC6H4COOH. A colorless (or white), bitter-tasting solid, it is a precursor to and a active metabolite, metabolite of acetylsalicylic acid (aspirin). It is a plant hormone, and has been lis ...
, and certain medicines like
imiquimod
Imiquimod, sold under the brand name Aldara among others, is a medication that acts as an immune response modifier that is used to treat genital warts, superficial basal cell carcinoma, and actinic keratosis.
Scientists at 3M's pharmaceutica ...
* Irritant or corrosive fluids from plants, such as
latex
Latex is an emulsion (stable dispersion) of polymer microparticles in water. Latices are found in nature, but synthetic latices are common as well.
In nature, latex is found as a wikt:milky, milky fluid, which is present in 10% of all floweri ...
or
resin
A resin is a solid or highly viscous liquid that can be converted into a polymer. Resins may be biological or synthetic in origin, but are typically harvested from plants. Resins are mixtures of organic compounds, predominantly terpenes. Commo ...
s from various species of ''
Ficus
''Ficus'' ( or ) is a genus of about 850 species of woody trees, shrubs, vines, epiphytes and hemiepiphytes in the family (biology), family Moraceae. Collectively known as fig trees or figs, they are native throughout the tropics with a few spe ...
'', ''
Euphorbia
''Euphorbia'' is a large and diverse genus of flowering plants, commonly called spurge, in the family (biology), family Euphorbiaceae.
Euphorbias range from tiny annual plants to large and long-lived trees, with perhaps the tallest being ''Eu ...
'', ''
Carica
''Carica'' is a genus of flowering plants in the family Caricaceae including the papaya (''C. papaya'' syn. ''C. peltata'', ''C. posoposa''), a widely cultivated fruit tree native to the American tropics.
The genus was formerly treated as inc ...
'', or ''
Taraxacum
''Taraxacum'' () is a genus of flowering plants in the family Asteraceae, which consists of species commonly known as dandelions. The scientific and hobby study of the genus is known as taraxacology. The genus has a near-cosmopolitan distribu ...
''
*
refrigerant
A refrigerant is a working fluid used in the cooling, heating, or reverse cooling/heating cycles of air conditioning systems and heat pumps, where they undergo a repeated phase transition from a liquid to a gas and back again. Refrigerants are ...
s, which kill the tissue by freezing; examples include liquid nitrogen, solid
carbon dioxide
Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...
, and its solution in
ether
In organic chemistry, ethers are a class of compounds that contain an ether group, a single oxygen atom bonded to two separate carbon atoms, each part of an organyl group (e.g., alkyl or aryl). They have the general formula , where R and R� ...
Escharotics have long been used in medicine. In conventional modern practice some still are useful for topical treatment of growths such as warts. For lack of anything better in the past, escharotics once were more widely used, and for example, popular products included so-called
black salve
Black salve, also known by the brand name Cansema, is an ineffective and unsafe alternative cancer treatment. The product is commonly classified as an escharotic—a topical paste which destroys skin tissue and leaves behind a scar called an es ...
s, with ingredients such as
zinc chloride
Zinc chloride is an Inorganic chemistry, inorganic chemical compound with the chemical formula, formula ZnCl2·''n''H2O, with ''n'' ranging from 0 to 4.5, forming water of hydration, hydrates. Zinc chloride, anhydrous and its hydrates, are colo ...
, plus sanguinarine in the form of bloodroot extract. These and others were traditional as topical treatments for localised skin cancers in
herbal medicine
Herbal medicine (also called herbalism, phytomedicine or phytotherapy) is the study of pharmacognosy and the use of medicinal plants, which are a basis of traditional medicine. Scientific evidence for the effectiveness of many herbal treatments ...
. They combined unreliability in eradication of the cancer, with harmful effects such as scarring, serious injury, and disfigurement. Consequently escharotic salves now are strictly regulated in most western countries, and available on prescription only. Some prosecutions have been pursued over unlicensed sales of escharotic products such as
Cansema.
See also
*
Wound healing
Wound healing refers to a living organism's replacement of destroyed or damaged tissue by newly produced tissue.
In undamaged skin, the epidermis (surface, epithelial layer) and dermis (deeper, connective layer) form a protective barrier again ...
References
External links
{{Medical resources
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, MedlinePlus = 002355
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Medical Separation of the Eschar
Cutaneous conditions
Necrosis