Keloid

A scar that doesn't know when to stop. When the skin is injured, cells grow back to fill in the gap. Somehow, they normally "know" when the scar tissue is level with the skin, at which point the cells stop multiplying. When the cells keep on reproducing, the result is a what is called a overgrown (hypertrophic) scar or a keloid. The result is a keloid — a tough heaped-up scar that rises quite abruptly above the rest of the skin. It is irregularly shaped and tends to enlarge progressively. In other words, keloids are due to an excessive response to trauma such as a cut to the skin. In creating a normal scar, connective tissue in the skin is repaired by the formation of collagen. This occurs in the dermis (the layer of skin just below the epidermis, the outer layer of skin). Keloids arise when there is too much collagen formed in the dermis during the repair of connective tissue. To develop keloids, a person must be susceptible to keloid formation. This susceptibility is clearly genetic. For instance, keloids are known to have occurred in 5 successive generations within a single family. People of African or Asian descent are more likely to get keloids than people with lighter skin. These peoples tend to have keloid susceptibility genes. This tendency to form keloids is important when someone of African or Asian descent is considering elective plastic surgery; the surgery can cause more trouble than it cures. The dense tumorlike scar was called a "keloid" ("chéloďde" in French) in 1835 by the dermatologist Jean-Louis Albert. However, the word "keloid" was already in use in France as early as 1817, according to the Nouveau Petit Robert Dictionaire. The origin of the term "keloid" is not entirely certain. The Petit Robert attributes it to the Greek word "chele" meaning in French "pince" and in English "a talon, claw, or hoof." Other authorities such as Dorland's Illustrated Medical Dictionary attribute "keloid" to the Greek " kelis", "blemish" or to the Greek "kele", "a rupture."

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A nodular, firm, movable, nonencapsulated, often linear mass of hyperplastic scar tissue, tender and frequently painful, consisting of wide irregularly distributed bands of collagen; occurs in the dermis and adjacent subcutaneous tissue, usually after trauma, surgery, a burn, or severe cutaneous disease such as cystic acne, and is more common in blacks. SYN: cheloid. [G. kele, a tumor (or kelis, a spot), + eidos, appearance]

- acne k. a chronic eruption of fibrous papules that develop at the site of deep folliculitis, usually on the back of the neck at the hairline. SYN: folliculitis keloidalis.

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ke·loid also che·loid 'kē-.lȯid n a thick scar resulting from excessive growth of fibrous tissue and occurring esp. after burns or radiation injury

keloid adj

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n.

an overgrowth of fibrous scar tissue following trauma to the skin. It does not resolve spontaneously but may be flattened by applied pressure or with injections of potent corticosteroids. Keloid formation is particularly common at certain sites, such as the breastbone or ear lobe; surgical excision of benign (nonmalignant) lesions from such sites is therefore best avoided. See also scar.

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ke·loid (keґloid) [Gr. kēlis blemish + -oid] a sharply elevated, irregularly shaped, progressively enlarging scar due to formation of excessive amounts of collagen in the dermis during connective tissue repair.

Keloids.