- Risk Factors
- Signs & Symptoms
What is a keloid scar?
Keloids can be considered to be "scars that don't know when to stop." A keloid sometimes referred to as a keloid scar, is a tough heaped-up scar that rises quite abruptly above the rest of the skin. It usually has a smooth top and a pink or purple color. Keloids are irregularly shaped and tend to enlarge progressively. Unlike scars, keloids do not regress over time.
What is the cause of keloids?
Doctors do not understand exactly why keloids form. Alterations in the cellular signals that control proliferation and inflammation may be related to the process of keloid formation, but these changes have not yet been characterized sufficiently to explain this defect in wound healing.
Keloids and piercing
Keloids can develop following the minor injuries that occur with body piercing. Since this form of physical adornment has become popular, the presence of keloidal scarring is much more prevalent. Since doctors do not understand the precise reasons why some people are more prone to developing keloids, it is impossible to predict whether one's first piercing will lead to keloid formation.
- Although some families seem prone to forming keloids, for the most part, it's impossible to tell who will develop a keloid.
- One person might, for instance, develop a keloid in one earlobe after piercing and not in the other. It makes sense, however, for someone who has formed one keloid to avoid any elective surgery or cosmetic piercing of any body part.
What are the risk factors for keloid?
Individuals with darkly pigmented skin are 15 times more likely to develop keloids, with those of African, Hispanic, and Asian ethnicity at greatest risk. Keloids are equally common in women and men. They are less common in children and the elderly.
Although people with darker skin are more likely to develop them, keloids can occur in people of all skin types.
In some cases, the tendency to form keloids seems to run in families. A mutation in a gene known as the NEDD4 gene may indicate that a person has a predisposition to keloid formation.
What are symptoms and signs of keloid?
Keloids are raised and look shiny and dome-shaped, ranging in color from pink to red. Some keloids become quite large and unsightly.
Aside from causing potential cosmetic problems, these exuberant scars tend to be itchy, tender, or even painful to the touch.
In which area of the body are keloids most likely to appear?
Keloids develop most often on the chest, back, shoulders, and earlobes. They seldom develop on the face (with the exception of the jawline).
What types of doctors diagnose and treat keloids?
Dermatologists, plastic surgeons, and certain family physicians generally diagnose and treat keloids with occasional help from therapeutic radiologists.
What is the difference between a keloid, hypertrophic scar, and a dermatofibroma?
After the skin is injured, the healing process usually leaves a flat scar. Sometimes the scar is hypertrophic, or thickened, but confined to the margin of the original wound.
- Hypertrophic scars tend to be redder and often regress spontaneously (a process that can take one year or more). Treatment, such as injections of cortisone (steroids), can speed up this process.
- A dermatofibroma is a small, benign, pigmented, very firm bump in the skin that does not cause other symptoms. It is most often found on the legs. Dermatofibromas are rarely larger than ½ to ¾ of an inch and remain unchanged over many years.
- Keloids, by contrast, may start sometime after a cutaneous injury and extend beyond the wound site. This tendency to migrate into surrounding areas that weren't injured originally distinguishes keloids from hypertrophic scars. Keloids typically appear following surgery or injury, but they can also as a result of some minor inflammation, such as an acne pimple on the chest (even one that wasn't scratched or otherwise irritated). Other minor injuries that can trigger keloids are burns and cosmetic piercings.
- A keloid has a characteristic microscopic appearance and may be distinguished from a hypertrophic scar and a dermatofibroma.
How do you treat a keloid scar?
The nine possible procedures now available to treat keloids are as follows:
- Corticosteroid injections (intralesional steroids): These are safe but moderately painful. Injections are usually given once every four to eight weeks into the keloids) and usually help flatten keloids; however, steroid injections can also make the flattened keloid redder by stimulating the formation of more superficial blood vessels. (These can be treated using a laser; see below.) The keloid may look better after treatment than it looked to start with, but even the best results leave a mark that looks and feels quite different from the surrounding skin.
- Surgery: This is risky because cutting a keloid can trigger the formation of a similar or even larger keloid. Some surgeons achieve success by injecting steroids or applying compression (using a specialized pressure device where appropriate) to the wound site for months after cutting away the keloid. Superficial radiation treatment after surgical excision has also been found to be useful.
- Laser: The pulsed-dye laser can be effective at flattening keloids and making them look less red. Treatment is safe and not very painful, but several treatment sessions may be needed. These may be costly since such treatments are not generally covered by insurance plans.
- Silicone gel or sheeting: This involves wearing a sheet of silicone gel on the affected area continuously for months, which is hard to sustain. Results are variable. Some doctors claim similar success with compression dressings made from materials other than silicone.
- Pressure: Special earrings are available, which when used appropriately, can cause keloids on the earlobe to shrink significantly.
- Cryotherapy: Freezing keloids with liquid nitrogen may flatten them but often darkens or lightens the site of treatment.
- Interferon: Interferons are proteins produced by the body's immune systems that help fight off viruses, bacteria, and other challenges. In recent studies, injections of interferon have shown promise in reducing the size of keloids, though it's not yet certain whether that effect will be lasting. Current research is underway using a variant of this method, applying topical imiquimod (Aldara), which stimulates the body to produce interferon.
- Fluorouracil and bleomycin: Injections of these chemotherapeutic (anti-cancer) agents, alone or together with steroids, have been used for the treatment of keloids.
- Radiation: Some doctors have reported the safe and effective use of radiation to treat keloids using a variety of techniques.
Is it possible to remove a keloid?
The decision about when to treat a keloid depends on the symptoms associated with its development and its anatomical location. A chronically itchy and irritated keloid can be quite distracting. Keloids in cosmetically sensitive areas that cause disfigurement or embarrassment are obvious candidates for treatment.
- It is unclear whether early treatment is important.
- What is clear is that larger keloids are more difficult to treat.
- Special techniques must be used soon after the surgical procedure has concluded to prevent the formation of a new, larger keloid.
What is the prognosis for keloids?
Small keloids can be effectively treated using a variety of methods. Generally, a series of injections of steroids into the problem area is the simplest and safest approach. The patient needs to understand that the keloid will never entirely disappear but is likely to become less symptomatic and flatter. Larger lesions are more difficult to treat.
Is keloid prevention possible?
The best way to deal with a keloid is not to get one. A person who has had a keloid should not undergo elective or cosmetic skin surgeries or procedures such as piercing. When it comes to keloids, prevention is crucial, because current treatments leave a lot to be desired.
Berman, Brian, Andrea Maderal, and Brian Raphael. "Keloids and Hypertrophic Scars: Pathophysiology, Classification, and Treatment." Dermatol Surg 43 (2017): S3-S18.
He, Yongjing, et al. "From Genetics to Epigenetics: New Insights Into Keloid Scarring." Cell Proliferation 2017; e12326; DOI: 10.1111/cpr.12326: 1-8.
Marneros, Alexander G. "A Role for the E3 Ubiquitin Ligase NEDD4 in Keloid Pathogenesis." Journal of Investigative Dermatology 2018. doi:10.1016/j.jid.2018.09.007.
Ogawa, Rei. "Keloid and Hypertrophic Scars Are the Result of Chronic Inflammation in the Reticular Dermis." International Journal of Molecular Sciences 18 (2017): 606.
Shockman, Soloman, Kapila V. Paghdal, and George Cohen. "Medical and Surgical Management of Keloids: A Review." Journal of Drugs in Dermatology 9.10 Oct. 2010: 1249-1257.
Thierauf, Julia, et al. "Treatment of Ear Keloids: Algorithm for a Multimodal Therapy Regimen." Eur Arch Otorhinolaryngol DOI: 10.1007/s00405-017-4714-5.
Trace, Anthony P., et al. "Keloids and Hypertrophic Scars: A Spectrum of Clinical Challenges." Am J Clin Dermatol Feb 19, 2016.
Xu, Jing, et al. "Radiation Therapy in Keloids Treatment: History, Strategy, Effectiveness, and Complication." Chin Med J 130 (2017): 1715-21.
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