Keloids are overgrowths of fibrous tissue or scars that can occur after an injury to the skin. These heavy scars are also called cheloid or hypertrophic scars. In individuals prone to keloids, even minor traumas to the skin, such as ear piercing, can cause keloids. The word "keloid" itself comes from the Greek word for a crab's claw; it was first used by a French physician to describe the way that keloids grow sideways into normal skin.
Keloids can occur anywhere on the body, but they are most common on the earlobes, upper back, shoulders, and chest. The pattern of distribution of keloids differs according to race, with facial keloids more common in Caucasians and relatively uncommon in Asians. African Americans are more likely to develop keloids on the legs or feet than either Asians or Caucasians. In general, keloids consist of hard, raised scars that may be slightly pink or whitish. These may itch and be painful, and some keloids can grow to be quite large.
Causes and symptoms
Although the cause of keloids is unknown, it is thought that they are due to the body's failure to turn off the healing process needed to repair skin. When this occurs, extra collagen forms at the site of the scar, and keeps forming because it is not shut off. This results in keloid formation.
Keloids occur most frequently in individuals of African-American descent and in those with darker skin. They are more common in Polynesians and Chinese than in people from India or Malaysia. Caucasians are the least frequently affected by keloids. Other risk factors include a family history of keloids, surgery, acne, burns, ear piercing, vaccinations, or even insect bites. Spontaneous keloids have been reported occasionally in siblings. In addition, women and young people under the age of 30 are more prone to develop them. Keloids are infrequent among the elderly.
Although the association of keloids with darker skin pigmentation suggests a genetic linkage of some sort, no specific genes have been identified in connection with keloids as of the early 2000s.
Initially, keloids will begin as a small lump where the skin has been injured. This lump grows and can eventually become very large and cosmetically unacceptable.
A dermatologist can usually make the diagnosis of a keloid based on looking at the scar. In some cases, however, a biopsy may be necessary to rule out other types of skin lesions, such as tumors.
The treatment of choice for keloids is usually an injection of corticosteroid drugs such as cortisone directly into the lesion. These injections cause the keloid to become atrophic, or thinner, and are repeated every three to four weeks until the keloid has been resolved to the individual's satisfaction. Other therapies include laser treatment or radiation therapy, and topical treatments are undergoing study.
Surgery is often used in combination with corticosteroid injections. The injections are given for several weeks, and then the keloid is surgically removed. The injections are then continued for several weeks. Surgical removal of the keloid may also be used in conjunction with radiation therapy, which delivers small amounts of radiation to the affected area.
Another surgical option is cryosurgery, in which liquid nitrogen is used to freeze the tissues in the keloid. The treatment may need to be repeated to remove as much of the keloid as possible; however, cryosurgery prevents keloids from recurring in about 70% of patients.
Newer approaches include silastic gel sheeting, which makes use of pressure to flatten the keloid. The gel is applied and kept securely in place with tape, cloth, or an Ace bandage. The dressing is to be changed every seven to 10 days for as long as 12 months.
Finally, researchers are now studying a type of tape that has been soaked with steroids, which are released slowly into the keloid, causing it to thin over time.
Newer treatments include injections of interferon directly into the keloids, and local application of 5% imiquimod cream, which induces the skin where it is applied to produce interferon. The imiquimod cream is reported to significantly lower the risk of keloid recurrence.
Although keloids are unsightly, they are not life-threatening. Keloids do not have a tendency to develop into malignancies, but they can become cosmetically unacceptable. Keloids can gradually lessen after treatment, but many recur. And just as they can occur spontaneously, they can also resolve spontaneously.
Preventive measures include avoiding any trauma to the skin, and compression pressure dressing for high-risk patients who have suffered burns to their skin. Patients with a tendency to form keloids should avoid any sort of elective surgery. Individuals who are prone to develop keloids or who have a history of keloids should immediately care for any cuts or abrasions they may sustain.
To lower the risk of keloids, surgeons are advised to close incisions with as little tension on the sutures as possible, and to use buried sutures whenever possible.
Atrophy— A wasting away of, becoming thinner, less strong.
Corticosteroids— Any of several steroid medications used to suppress inflammation, allergic, or immune responses of the body.
Cryosurgery— The use of extreme cold to kill or remove tissue.
Beers, Mark H., MD, and Robert Berkow, MD., editors. "Benign Tumors." Section 10, Chapter 125 In The Merck Manual of Diagnosis and Therapy. Whitehouse Station, NJ: Merck Research Laboratories, 2004.
Berman, Brian, MD, PhD, and Sonia Kapoor, MBBS. "Keloid and Hypertrophic Scar." eMedicine November 30, 2001. 〈http://www.emedicine.com/derm/topic205.htm〉.
Dinh, Q., M. Veness, and S. Richards. "Role of Adjuvant Radiotherapy in Recurrent Earlobe Keloids." Australasian Journal of Dermatology 45 (August 2004): 162-166.
Mandal, A., D. Imran, and G. S. Rao. "Spontaneous Keloids in Siblings." Irish Medical Journal 97 (September 2004): 250-251.
American Academy of Dermatology. 930 N. Meacham Road, PO Box 4014, Schaumburg, IL 60168-4014. (847) 330-0230. Fax: (847) 330-0050. 〈http://www.aad.org〉.
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"Keloids." Gale Encyclopedia of Medicine, 3rd ed.. . Encyclopedia.com. (October 20, 2018). http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/keloids
"Keloids." Gale Encyclopedia of Medicine, 3rd ed.. . Retrieved October 20, 2018 from Encyclopedia.com: http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/keloids
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