With the exception of very minor lesions, every wound (e.g., after accident, disease, or surgery) results in some degree of scarring.

High melanin levels and either African or Asian ancestry may make adverse scarring more noticeable.

Although they can be a cosmetic problem, keloid scars are only inert masses of collagen and therefore completely harmless and not cancerous.

This type of scarring is often associated with acne,[9][10] chickenpox, other diseases (especially Staphylococcus infection), surgery, certain insect and spider bites, or accidents.

Egg-laying animals have an umbilical scar which, depending on the species, may remain visible for life or disappear within a few days after birth.

If a wound heals quickly within two weeks with new formation of skin, minimal collagen will be deposited and no scar will form.

[18] Small full thickness wounds under 2mm reepithelize fast and heal scar free.

[26][citation needed] Scars form differently based on the location of the injury on the body and the age of the person who was injured.

[8] An injury does not become a scar until the wound has completely healed; this can take many months, or years in the worst pathological cases, such as keloids.

Over time, the fibroblasts continue to crawl around the matrix, adjusting more fibers and, in the process, the scarring settles and becomes stiff.

[citation needed] Generally, the myofibroblasts disappear from the wound within 30 days,[32] but can remain in pathological cases in hypertrophy, such as keloids.

[31][32] Myofibroblasts have plasticity and in mice can be transformed into fat cells, instead of scar tissue, via the regeneration of hair follicles.

[50] A meta-study by the Cochrane collaboration found weak evidence that silicone gel sheeting helps prevent scarring.

[51] Pressure dressings are commonly used in managing burn and hypertrophic scars, although supporting evidence is lacking.

[52] Care providers commonly report improvements, however, and pressure therapy has been effective in treating ear keloids.

[52] Verapamil, a type of calcium channel blocker, is considered a candidate drug for the treatment of hypertrophic scars.

A study conducted by the Catholic University of Korea concluded that verapamil-releasing silicone gel is effective and is a superior alternative to the conventional silicone gel where decreased median SEI, fibroblast count, and collagen density in all verapamil-added treatment groups were observed.

This was verified with quantifiable histomorphometric parameters; however, oral verapamil is not a good choice because of its effect of lowering blood pressure.

Topical silicone gel combined with verapamil does not lead to systemic hypotension, is convenient to apply, and shows enhanced results.

Deeper cuts need a multilayered closure to heal optimally, otherwise depressed or dented scars can result.

A clinical study is currently ongoing to assess the benefits of a treatment combining surgery and laser-assisted healing in hypertrophic or keloid scars.

Subcision is a process used to treat deep rolling scars left behind by acne or other skin diseases.

Once the skin has leveled, treatments such as laser resurfacing, microdermabrasion or chemical peels can be used to smooth out the scarred tissue.

[58] Research shows the use of vitamin E and onion extract (sold as Mederma) as treatments for scars is ineffective.

First attested in English in the late 14th century, the word scar derives from a conflation of Old French escharre, from Late Latin eschara,[64] which is the Latinisation of the Greek ἐσχάρα (eskhara), meaning "hearth, fireplace", but in medicine "scab, eschar on a wound caused by burning or otherwise",[65][66] and Middle English skar ("cut, crack, incision"), which is from Old Norse skarð ("notch, gap").

Treatments involving molecular mechanisms including avotermin,[67][68] ribosomal s6 kinase (RSK),[69] and osteopontin[70][71] were investigated at the time.

and scar-free healing had been operationalized and induced by four main regeneration techniques: by instrument, by materials, by drugs, and by in vitro 3-D printing.

In 2018, a silk-derived sericin hydrogel dressing was undergoing research, the material was shown to prevent scar formation.

[74] In 2021, researchers found that, verteporfin, an FDA-approved drug for eye disease, could enable scar-free healing in mice.