Keloid
Keloid | |
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Bulky keloid forming at the site of abdominal surgery | |
Pronunciation | |
Specialty | Dermatology |
Usual onset | scar formation |
Keloid, also known as keloid disorder and keloidal scar,
Keloids should not be confused with hypertrophic scars, which are raised scars that do not grow beyond the boundaries of the original wound.
Signs and symptoms
Keloids expand in claw-like growths over normal skin.[3] They have the capability to hurt with a needle-like pain or to itch, the degree of sensation varying from person to person.[citation needed]
Keloids form within
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Location
Keloids can develop in any place where skin trauma has occurred. They can be the result of pimples, insect bites, scratching, burns, or other skin injury. Keloid scars can develop after surgery. They are more common in some sites, such as the central chest (from a
Cause
Most skin injury types can contribute to scarring. This includes burns, acne scars, chickenpox scars, ear piercing, scratches, surgical incisions, and vaccination sites.
According to the US National Center for Biotechnology Information, keloid scarring is common in young people between the ages of 10 and 20. Studies have shown that those with darker complexions are at a higher risk of keloid scarring as a result of skin trauma. They occur in 15–20% of individuals with sub-Saharan African, Asian or Latino ancestry, significantly less in those of a Caucasian background. Although it was previously believed that people with albinism did not get keloids,[5] a recent report described the incidence of keloids in Africans with albinism.[6] Keloids tend to have a genetic component, which means one is more likely to have keloids if one or both of their parents has them. However, no single gene has yet been identified which is a causing factor in keloid scarring but several susceptibility loci have been discovered, most notably in Chromosome 15.[5][7]
Genetics
People who have ancestry from Sub-Saharan Africa, Asia, or Latin America are more likely to develop a keloid. Among ethnic Chinese in Asia, the keloid is the most common skin condition. In the United States, keloids are more common in African Americans and Hispanic Americans than European Americans. Those who have a family history of keloids are also susceptible since about 1/3 of people who get keloids have a first-degree blood relative (mother, father, sister, brother, or child) who also gets keloids. This family trait is most common in people of African and/or Asian descent.
Development of keloids among twins also lends credibility to existence of a genetic susceptibility to develop keloids. Marneros et al. (1) reported four sets of identical twins with keloids; Ramakrishnan et al.[8] also described a pair of twins who developed keloids at the same time after vaccination. Case series have reported clinically severe forms of keloids in individuals with a positive family history and black African ethnic origin.
Pathology
Keloids affect all 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
Treatments
Prevention of keloid scars in patients with a known predisposition to them includes preventing unnecessary trauma or surgery (such as ear piercing and 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.
Treatments (both preventive and therapeutic) available are pressure therapy,
In adults, corticosteroids combined with 5-FU and PDL in a triple therapy, enhance results and diminish side effects.[11]
Cryotherapy (or cryosurgery) refers to the application of extreme cold to treat keloids. This treatment method is easy to perform, effective and safe and has the least chance of recurrence.[12][13]
Surgical excision is currently still the most common treatment for a significant amount of keloid lesions. However, when used as the solitary form of treatment there is a large recurrence rate of between 70 and 100%. It has also been known to cause a larger lesion formation on recurrence. While not always successful alone, surgical excision when combined with other therapies dramatically decreases the recurrence rate. Examples of these therapies include but are not limited to radiation therapy, pressure therapy and laser ablation. Pressure therapy following surgical excision has shown promising results, especially in keloids of the ear and earlobe. The mechanism of how exactly pressure therapy works is unknown at present, but many patients with keloid scars and lesions have benefited from it.[5]
Intralesional injection with a corticosteroid such as
Tea tree oil, salt or other topical oil has no effect on keloid lesions.[15]
A 2022 systematic review included multiple studies on laser therapy for treating keloid scars. There was not enough evidence for the review authors to determine if laser therapy was more effective than other treatments. They were also unable to conclude if laser therapy leads to more harm than benefits compared with no treatment or different kinds of treatment.[16]
Another 2022 systematic review compared silicone gel sheeting with no treatment, treatment with non-silicone gel sheeting and treatment with intralesional injections of triamcinolone acetonide. The authors only found two small studies (36 participants in total) that compared these treatment options so were unable to determine which (if any) was more effective.[17]
Epidemiology
Persons of any age can develop a keloid. Children under 10 are less likely to develop keloids, even from ear piercing. Keloids may also develop from pseudofolliculitis barbae; continued shaving when one has razor bumps will cause irritation to the bumps, infection, and over time keloids will form. Persons with razor bumps are advised to stop shaving in order for the skin to repair itself before undertaking any form of hair removal. The tendency to form keloids is speculated to be hereditary.[18] Keloids can tend to appear to grow over time without even piercing the skin, almost acting out a slow tumorous growth; the reason for this tendency is unknown.
Extensive burns, either thermal or radiological, can lead to unusually large keloids; these are especially common in firebombing casualties, and were a signature effect of the atomic bombings of Hiroshima and Nagasaki.
True incidence and prevalence of keloid in United States is not known. Indeed, there has never been a population study to assess the epidemiology of this disorder. In his 2001 publication, Marneros[19] stated that “reported incidence of keloids in the general population ranges from a high of 16% among the adults in the Democratic Republic of the Congo to a low of 0.09% in England,” quoting from Bloom's 1956 publication on heredity of keloids.[20] Clinical observations show that the disorder is more common among sub-Saharan Africans, African Americans and Asians, with unreliable and very wide estimated prevalence rates ranging from 4.5 to 16%.[21][22]
History
Keloids were described by Egyptian surgeons around 1700
The famous
Intralesional corticosteroid injections was introduced as a treatment in mid-1960s as a method to attenuate scarring.[24]
Pressure therapy has been used for prophylaxis and treatment of keloids since the 1970s.[24]
Topical silicone gel sheeting was introduced as a treatment in the early 1980s.[24]
References
- ISBN 978-1-4160-2999-1.
- S2CID 21364302.
- .
- ^ Cole GW (27 July 2022). Stöppler MC (ed.). "Keloid Scar: Find Causes, Symptoms, and Removal". MedicineNet. Retrieved 2016-02-11.
- ^ PMID 26844756.
- S2CID 20641975.
- ^ "Keloids". PubMed Health. U.S. National Library of Medicine. 5 October 2010. Archived from the original on 16 February 2011.
- PMID 4813760.
- ^ Wound Healing, Keloids at eMedicine
- PMID 20927486.
- ^ PMID 24767715.
- PMID 8363398.
- ^ "Keloid Research Foundation". 2016-11-07. Archived from the original on 2016-11-07. Retrieved 2020-07-13.
- PMID 5919603.
- ^ "Keloid Treatment". Texas Institute of Dermatology. Retrieved 22 November 2018.
- PMID 36161591.
- PMID 36594476.
- PMID 22783524.
- PMID 11708945.
- PMID 13288798.
- S2CID 25168874.
- PMID 20927486.
- ^ "Alibert's disease I". Whonamedit?.
- ^ PMID 20927486.
Further reading
- Roßmann N (2005). Beitrag zur Pathogenese des Keloids und seine Beeinflussbarkeit durch Steroidinjektionen [Contribution to the pathogenesis of the keloid and its influence by steroid injections] (PhD Thesis) (in German). OCLC 179740918.
- Ogawa R, Mitsuhashi K, Hyakusoku H, Miyashita T (February 2003). "Postoperative electron-beam irradiation therapy for keloids and hypertrophic scars: retrospective study of 147 cases followed for more than 18 months". Plastic and Reconstructive Surgery. 111 (2): 547–53, discussion 554–5. S2CID 8411788.
- Okada E, Maruyama Y (September 2007). "Are keloids and hypertrophic scars caused by fungal infection?". Plastic and Reconstructive Surgery. 120 (3): 814–815. PMID 17700144.