Home      Discussion      Topics      Dictionary      Almanac
Signup       Login
Keloid

Keloid

Overview
A keloid
is a type of scar
Scar
Scars are areas of fibrous tissue that replace normal skin after injury. A scar results from the biological process of wound repair in the skin and other tissues of the body. Thus, scarring is a natural part of the healing process. With the exception of very minor lesions, every wound results in...

, which depending on its maturity, is composed mainly of either type III (early) or type I (late) collagen
Collagen
Collagen is a group of naturally occurring proteins found in animals, especially in the flesh and connective tissues of mammals. It is the main component of connective tissue, and is the most abundant protein in mammals, making up about 25% to 35% of the whole-body protein content...

. It is a result of an overgrowth of granulation tissue (collagen type 3) at the site of a healed skin injury which is then slowly replaced by collagen type 1. Keloids are firm, rubbery lesions or shiny, fibrous nodules
Nodule (medicine)
For use of the term nodule in dermatology, see Nodule In medicine, a nodule refers to a relatively hard, roughly spherical abnormal structure....

, and can vary from pink to flesh-coloured or red to dark brown in colour.
Discussion
Ask a question about 'Keloid'
Start a new discussion about 'Keloid'
Answer questions from other users
Full Discussion Forum
 
Recent Discussions
Encyclopedia
A keloid
is a type of scar
Scar
Scars are areas of fibrous tissue that replace normal skin after injury. A scar results from the biological process of wound repair in the skin and other tissues of the body. Thus, scarring is a natural part of the healing process. With the exception of very minor lesions, every wound results in...

, which depending on its maturity, is composed mainly of either type III (early) or type I (late) collagen
Collagen
Collagen is a group of naturally occurring proteins found in animals, especially in the flesh and connective tissues of mammals. It is the main component of connective tissue, and is the most abundant protein in mammals, making up about 25% to 35% of the whole-body protein content...

. It is a result of an overgrowth of granulation tissue (collagen type 3) at the site of a healed skin injury which is then slowly replaced by collagen type 1. Keloids are firm, rubbery lesions or shiny, fibrous nodules
Nodule (medicine)
For use of the term nodule in dermatology, see Nodule In medicine, a nodule refers to a relatively hard, roughly spherical abnormal structure....

, and can vary from pink to flesh-coloured or red to dark brown in colour. A keloid scar is benign
Benign
A benign tumor is a tumor that lacks the ability to metastasize. Common examples of benign tumors include moles and uterine fibroids.The term "benign" implies a mild and nonprogressive disease. Indeed, many kinds of benign tumors are harmless to human health...

, non-contagious, but sometimes accompanied by severe itchiness and pain, and changes in texture. In severe cases, it can affect movement of skin.

Keloids should not be confused with hypertrophic scars, which are raised scars that do not grow beyond the boundaries of the original wound.

Occurrence


Keloids expand in claw-like growths over normal skin. They have the capability to hurt with a needle-like pain or to itch without warning, although the degree of sensation varies from patient to patient.

If the keloid becomes infected, it may ulcerate. Removing the scar is one treatment option, however may result in more severe consequences i.e. the probability that the resulting surgery scar will also become a keloid is high, usually greater than 50%. Laser treatment has also been used with varying degrees of success.

Keloids form within scar tissue
Scar
Scars are areas of fibrous tissue that replace normal skin after injury. A scar results from the biological process of wound repair in the skin and other tissues of the body. Thus, scarring is a natural part of the healing process. With the exception of very minor lesions, every wound results in...

. Collagen
Collagen
Collagen is a group of naturally occurring proteins found in animals, especially in the flesh and connective tissues of mammals. It is the main component of connective tissue, and is the most abundant protein in mammals, making up about 25% to 35% of the whole-body protein content...

, used in wound repair, tends to overgrow in this area, sometimes producing a lump many times larger than that of the original scar. Although they usually occur at the site of an injury, keloids can also arise spontaneously. They can occur at the site of a piercing and even from something as simple as a pimple or scratch. They can occur as a result of severe acne
Acne vulgaris
Acne vulgaris is a common human skin disease, characterized by areas of skin with seborrhea , comedones , papules , pustules , Nodules and possibly scarring...

 or chickenpox
Chickenpox
Chickenpox or chicken pox is a highly contagious illness caused by primary infection with varicella zoster virus . It usually starts with vesicular skin rash mainly on the body and head rather than at the periphery and becomes itchy, raw pockmarks, which mostly heal without scarring...

 scarring, infection at a wound site, repeated trauma to an area, excessive skin tension during wound closure or a foreign body in a wound. Keloids can sometimes be sensitive to chlorine. Keloid scars can grow, if they appear at a younger age, because the body is still growing.

Histologically, keloids are fibrotic tumors characterized by a collection of atypical fibroblasts with excessive deposition of extracellular matrix components, especially collagen, fibronectin, elastin, and proteoglycans. Generally, keloids contain relatively acellular centers and thick, abundant collagen bundles that form nodules in the deep dermal portion of the lesion. Keloids present a therapeutic challenge that must be addressed, as these lesions can cause significant pain, pruritus (itching), and physical disfigurement. They may not improve in appearance over time and can limit mobility if located over a joint.

Keloids affect both sexes equally, although the incidence in young female patients has been reported to be higher than in young males, probably reflecting the greater frequency of earlobe piercing among women.
There is a fifteen times higher frequency of occurrence in highly pigmented people. Persons of African descent are at increased risk of keloid occurrences.

History in medicine


Keloids were described by Egyptian surgeons around 1700 BC. Baron Jean-Louis Alibert
Jean-Louis-Marc Alibert
Jean-Louis-Marc Alibert was a French dermatologist born in Villefranche-de-Rouergue, Aveyron. He was a pioneer of French dermatology....

 (1768–1837) identified the keloid as an entity in 1806. He called them cancroïde, later changing the name to chéloïde to avoid confusion with cancer. The word is derived from the Greek χηλή, chele, meaning "hoof
Hoof
A hoof , plural hooves or hoofs , is the tip of a toe of an ungulate mammal, strengthened by a thick horny covering. The hoof consists of a hard or rubbery sole, and a hard wall formed by a thick nail rolled around the tip of the toe. The weight of the animal is normally borne by both the sole...

", here in the sense of "crab pincers", and the suffix -oid, meaning "like". For many years, Alibert's clinic at L'Hôpital Saint-Louis was the world’s center for dermatology
Dermatology
Dermatology is the branch of medicine dealing with the skin and its diseases, a unique specialty with both medical and surgical aspects. A dermatologist takes care of diseases, in the widest sense, and some cosmetic problems of the skin, scalp, hair, and nails....

.

Intentional keloids


The Olmec
Olmec
The Olmec were the first major Pre-Columbian civilization in Mexico. They lived in the tropical lowlands of south-central Mexico, in the modern-day states of Veracruz and Tabasco....

 of Mexico in pre-Columbian
Pre-Columbian
The pre-Columbian era incorporates all period subdivisions in the history and prehistory of the Americas before the appearance of significant European influences on the American continents, spanning the time of the original settlement in the Upper Paleolithic period to European colonization during...

 times used keloid scarification
Scarification
Scarifying involves scratching, etching, burning, or superficially cutting designs, pictures, or words into the skin as a permanent body modification.In the process of body scarification, scars are formed by cutting or branding the skin...

 as a means of decoration. In the modern era, women of Egypt are intentionally scarified with facial keloids as a means of decoration. The Nuer and Nuba
Nuba
Nuba is a collective term used here for the peoples who inhabit the Nuba Mountains, in Sudan, Africa. Although the term is used to describe them as if they composed a single group, the Nuba are multiple distinct peoples and speak different languages...

 use lip plugs, keloid tattoos along the forehead, keloid tattoos along the chin and above the lip, and cornrows. As a part of a ritual, the people of Papua New Guinea
Papua New Guinea
Papua New Guinea , officially the Independent State of Papua New Guinea, is a country in Oceania, occupying the eastern half of the island of New Guinea and numerous offshore islands...

 cut their skin and insert clay or ash into the wounds so as to develop permanent bumps (known as keloids or weals). This painful ritual honors members of their tribe who are celebrated for their courage and endurance.

Locations of keloids


Keloids can develop in any place that an abrasion has occurred. They can be the result of pimples, insect bites, scratching, burns, or other skin trauma. Keloid scars can develop after surgery.
They are more common in some sites such as central chest, the back and shoulders and the ear lobes. They can also occur on body piercings.
Most common spots are earlobes, arms, and over the collar bone.

Incidence


People of all ages can develop a keloid. Children under 11 are less likely to develop keloids, even when they get their ears pierced. Keloids may also develop from pseudofolliculitis barbae
Pseudofolliculitis barbae
Pseudofolliculitis barbae , also known as barber's itch, folliculitis barbae traumatica, razor bumps, scarring pseudofolliculitis of the beard, and shave bumps, is a medical term for persistent irritation caused by shaving....

, continued shaving when one has razor bumps will cause irritation to the bumps (a possible location for future cancerous growth), infection and over time keloids will form. It would thus be wise for a person with razor bumps to stop shaving for a while and have the skin repair itself first before undertaking any form of hair removal. It is also speculated that the tendency to form keloids is hereditary and may be passed down from generation to generation.Keloids can tend to appear to grow over the years without even piercing the skin, almost acting out like a slow fungus growth, and the reason for this is unknown. If a Keloid shall grow too big, removal is the only solution, resulting in a scar or in worse cases amputation.

Treatments


The best treatment is prevention in patients with a known predisposition. This includes preventing unnecessary trauma or surgery (including ear piercing, elective mole removal), whenever possible. Any skin problems in predisposed individuals (e.g., acne, infections) should be treated as early as possible to minimize areas of inflammation.
  • lntra-lesional corticosteroids — Intra-lesional corticosteroid
    Corticosteroid
    Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex. Corticosteroids are involved in a wide range of physiologic systems such as stress response, immune response and regulation of inflammation, carbohydrate metabolism, protein catabolism, blood electrolyte...

    s are first-line therapy for most keloids. A systematic review found that up to 70 percent of patients respond to intra-lesional corticosteroid injection with flattening of keloids, although the recurrence rate is high in some studies (up to 50 percent at five years) While corticosteroids are one of the more common treatments, injections into and in close proximity to keloid tissue can be highly painful and can produce undesirable results in female patients, as per any other testosterone-based treatment.
  • Excision — Scalpel excision may be indicated if injection therapy alone is unsuccessful or unlikely to result in significant improvement. Excision should be combined with preoperative, intraoperative, or postoperative triamcinolone or interferon injections. Recurrence rates from 45 to 100 percent have been reported in patients treated with excision alone; this falls to below 50 percent in patients treated with combination therapy.
  • Silicone gel sheeting — Silicone gel sheeting
    Silicone scar sheet
    Silicone scar sheets are a type of treatment used to prevent the formation of new scars and to reduce the appearance of existing scars. The scar sheet is lined on one side with silicone gel. The other side is often lined with a smooth fabric or a transparent film...

     has been used for the treatment of symptoms (e.g., pain and itching) in patients with established keloids as well as for the management of evolving keloids and the prevention of keloids at the sites of new injuries. A systematic review of controlled trials found some evidence that silicone gel sheeting may reduce the incidence of abnormal scarring, but concluded that any estimate of effect was uncertain because the underlying trials were of poor quality and highly susceptible to bias. Treatment with silicone gel sheeting appeared in some studies to improve elasticity of established abnormal scars, but the evidence was again of poor quality and susceptible to bias.
  • Cryosurgery — Cryosurgery
    Cryosurgery
    Cryosurgery is the application of extreme cold to destroy abnormal or diseased tissue. The term comes from the Greek words cryo and surgery meaning "hand work" or "handiwork"....

     is most useful in combination with other treatments for keloids. The major side effect is permanent hypopigmentation
    Hypopigmentation
    Hypopigmentation is the loss of skin color. It is caused by melanocyte or melanin depletion, or a decrease in the amino acid tyrosine, which is used by melanocytes to make melanin.-Treatments:...

    , limiting its use in people with darker skin.
  • Radiation therapy
    Radiation therapy
    Radiation therapy , radiation oncology, or radiotherapy , sometimes abbreviated to XRT or DXT, is the medical use of ionizing radiation, generally as part of cancer treatment to control malignant cells.Radiation therapy is commonly applied to the cancerous tumor because of its ability to control...

     — Most studies, but not all, have found radiation therapy to be highly effective in reducing keloid recurrence, with improvement rates of 70 to 90 percent when administered after surgical excision. A small randomized trial of treatments after surgery found recurrences in two of sixteen earlobe keloids (13 percent) treated with radiation therapy and in four of twelve earlobe keloids (33 percent) treated with steroid injections. However, concern regarding the potential long-term risks (e.g., malignancy) associated with using radiation for an essentially benign disorder limits its utility in most patients. Only a few cases of malignancy that may have been associated with radiation therapy for keloids have been reported. Although causation cannot be confirmed in these cases, caution should still be used when prescribing radiation therapy for keloids, particularly when treating younger patients. Radiation therapy may occasionally be appropriate as treatment for keloids that are resistant to other therapies. In addition, radiation therapy may be indicated for lesions that are not amenable to resection.
  • Interferon alpha — Interferon alpha
    Interferon
    Interferons are proteins made and released by host cells in response to the presence of pathogens—such as viruses, bacteria, or parasites—or tumor cells. They allow communication between cells to trigger the protective defenses of the immune system that eradicate pathogens or tumors.IFNs belong to...

     injections may reduce recurrence rates postoperatively. However, all currently available studies of interferon therapy suffer from methodologic problems, making an evidence-based recommendation regarding its use difficult.
  • Pulsed dye laser — Pulsed dye laser
    Dye laser
    A dye laser is a laser which uses an organic dye as the lasing medium, usually as a liquid solution. Compared to gases and most solid state lasing media, a dye can usually be used for a much wider range of wavelengths. The wide bandwidth makes them particularly suitable for tunable lasers and...

    treatment can be beneficial for keloids, and appears to induce keloid regression through suppression of keloid fibroblast proliferation, and induction of apoptosis and enzyme activity. Combination treatment with pulsed dye laser plus intralesional therapy with corticosteroids and/or fluorouracil may be superior to either approach alone.

Case presentation


This is a young male with bilateral keloid formation on the plantar surfaces of both feet. He has never been treated for this condition. There are other much smaller keloids located at small inlets on the glabrous (hairless) skin.

External links