A guide for the first contact clinician
Jamie is 15 and presents to the ED 3 weeks after an operation following a left-sided shoulder dislocation. They are worried about a thickened scar at one of the port sites from the operation…
What is keloid?
Keloid disorder refers to a group of conditions that lead to excessive scar formation, resulting in keloids and hypertrophic scars. These appear as firm, raised, smooth growths on the skin, often causing cosmetic concerns and, in some cases, discomfort.
Keloids develop following an injury to the skin, but they can occasionally form spontaneously. They can appear anywhere on the body, though they most commonly affect the upper torso (including the shoulders), ears, and neck. Unlike normal scars, keloids grow beyond the original wound boundary, continuing to expand over time.
In contrast, hypertrophic scars remain within the original wound margins. They tend to develop in areas of high tension, such as over joints and are thicker than scars from normal healing. Unlike keloids, hypertrophic scars are more likely to regress and gradually resolve over time.
Who is affected and why?
The exact cause of keloid disorder in children remains unclear. The leading theory suggests keloids result from a dysregulated healing process after skin injury. This triggers excessive production of collagen, elastin, extracellular matrix proteins, and proteoglycans. Fibroblasts and mast cells are more abundant in keloid tissue, alongside a higher concentration of inflammatory markers, contributing to persistent and uncontrolled scar growth.
Keloid development is significantly more common in individuals with darker skin tones. Some studies suggest that the risk is up to 15 times higher in dark-skinned patients compared to those with lighter skin. Reported prevalence rates vary, with estimates ranging from 4.5% to 16% in people of African descent, 0.15% to 0.6% in individuals of Asian heritage, and around 0.1% in Caucasians.
Keloid scarring is more commonly seen in individuals with Fitzpatrick skin types III to VI. However, research using more representative skin pigmentation scales, such as the Eumelanin Human Skin Colour Scale, remains limited. This gap in research makes it difficult to fully understand the true prevalence of keloid scarring across different skin tones.
In contrast, hypertrophic scarring occurs across all age groups and skin colours, without the same strong association with darker pigmentation.
Research into the causes of keloid formation is often limited by the variability of the studies analysed. However, some evidence suggests that females may be more prone to developing keloids. One proposed explanation is the influence of sex hormones, though the evidence remains inconclusive. Many studies focus on earlobe keloids, which introduces a potential confounder—females are more likely to have their ears pierced, increasing the risk of keloid formation at these sites.
Genetic predisposition is another key factor, with a positive family history being one of the strongest risk factors. A predominantly autosomal dominant pattern of inheritance has been suggested, meaning a child has a 50% chance of inheriting the condition if one parent carries the gene. However, this conflicts with the idea that keloids are more common in females, suggesting that multiple genetic and environmental factors may contribute.
Age also appears to play a role. Keloids are rare in prepubertal children, with most cases developing between 10 and 30. Several factors may explain this pattern. As previously mentioned, sex hormones could be involved, supported by observations of keloid growth during pregnancy. Another theory relates to immune system maturity—younger children (aged 1–10) have a less developed immune response than older children and adolescents. Since keloid formation is thought to require an exaggerated inflammatory response to injury, this could explain why keloids are less common in younger age groups.
While these theories are plausible, it is important to acknowledge the limitations of current research. Many studies rely on retrospective reviews, which carry a higher risk of recall bias. Additionally, small sample sizes reduce the internal validity and reproducibility of findings, making it difficult to draw firm conclusions. There is also a risk of overestimating effect sizes, meaning some proposed associations may appear stronger than they actually are. Further high-quality research is needed to better understand the mechanisms behind keloid formation.
After taking a history and examining Jamie, you note that the scar is occasionally itchy. It is pink in appearance and started looking like this within 2 weeks of commencing healing. It is limited to the borders of the original incision. Jamie can move their left shoulder without any restriction.
Clinical features
| Keloids | Hypertrophic scars |
| Purplish-red | Pink to red |
| Firm, smooth, raised | Slightly raised or flat |
| May be uncomfortable and itchy | May be uncomfortable and itchy |
| May occur years after injury | Usually develop within weeks of injury |
| Develop beyond the margin of the initial injury | Limited to the confines of the initial injury |
In children with darker skin, keloid disorder lesions tend to be less pink and more hyperpigmented.
Diagnosis
The diagnosis of keloids and hypertrophic scars is primarily clinical. However, in cases of diagnostic uncertainty, a skin biopsy can help distinguish between the two.
Histologically, several differences can be observed between keloids and hypertrophic scars:
| Keloids | Hypertrophic scars |
| Whorls and nodules of thick homogenous collagen bundles located irregularly throughout the dermal layer | Increased fibroblast number |
| But…the above may be absent in up to half of keloid scars | Increased dermal density of collagen fibres |
Differential Diagnosis
- Skin tumours, for example, adnexal tumours; Spitz Naevi, dermatofibromas
- Cutaneous squamous cell carcinoma
- Cutaneous pseudolymphoma
- Lobomycosis
- Morphea
Complications of Keloid
- Cosmetic disfigurement – Keloids can be large, raised, and visually prominent, which may cause distress for children and young people.
- Psychological impact – Visible keloids may contribute to low mood, reduced self-esteem, and decreased confidence, particularly in social settings. This can be exacerbated by bullying or teasing from peers, impacting a child’s emotional well-being.
- Limitation of movement – As keloids tend to develop in areas of high anatomical tension, thick, tight scars can restrict movement. In growing children, extensive keloid formation may also interfere with limb growth.
- Infection (rarely) – Although keloids are non-infectious, secondary bacterial infections can occur, particularly if the skin is repeatedly traumatised (e.g., from scratching).
- Malignancy risk – Both keloids and hypertrophic scars are benign. However, some studies suggest that individuals with keloids may have a slightly increased risk of skin cancer compared to those without keloids. While this remains rare, it is an important consideration in long-term follow-up.
Management of Paediatric Keloid Disorder: What Does the Evidence Say?
Hypertrophic scars often resolve on their own, but keloids are persistent and can be difficult to treat. The goals of treatment are to:
- Minimise functional problems, especially when keloids limit movement in high-tension areas
- Improve cosmetic appearance
- Reduce symptoms such as pain and itchiness
There are various treatment options available, including intralesional corticosteroid injections, surgery, and laser therapy. However, no single approach has been definitively proven superior, and this uncertainty is even more pronounced in paediatric cases.
Despite increasing use of laser therapy, high-quality research on its effectiveness remains limited. A 2022 Cochrane review examined 15 randomised controlled trials conducted over two decades, involving 604 participants. These studies varied significantly in methodology, sample size, and follow-up duration, with none of the trials employing blinding for participants or investigators. Due to these inconsistencies, the authors concluded that it remains unclear whether laser therapy is more or less effective than other treatments for keloids and hypertrophic scars. The review also found insufficient evidence to determine whether laser therapy carries greater risks compared to other treatment options or even placebo.
A more recent review by Hirsch and colleagues focused specifically on paediatric keloid disorder, analysing data from 13 studies involving 482 patients aged between three months and 18 years. However, key demographic details were often missing, as only a few studies provided breakdowns by age or sex, and just three studies documented family history of keloids. While all studies reported the primary injury leading to keloid formation, there was significant variability in study design and outcome measures.
Multimodal treatment was the most common approach, used in 76% of cases, with surgical excision and intralesional corticosteroid injection being the most frequently combined therapies. Other interventions included pressure therapy and laser treatment. Keloid recurrence was observed in 16.1% of lesions treated with multimodal therapy, compared to 30.4% in lesions treated with surgery alone. However, due to the heterogeneity of study designs and inconsistencies in measuring and reporting outcomes, these findings should be interpreted with caution.
While multiple treatment options exist, high-quality evidence remains lacking. Combination therapies appear to offer better outcomes in terms of recurrence, but further well-designed studies are needed to establish clear clinical guidelines for managing paediatric keloid disorder.
Jamie asks if anything can be done about the scar.
You advise that an emollient cream or oil massaged regularly into the scar may help with itchiness, but the scar may start looking normal in time, with or without treatment.
How to reduce the risk of keloid formation
With paediatric keloid disorder often developing after trauma, certain strategies can help reduce the risk of keloid or hypertrophic scar formation, particularly in children predisposed to excessive scarring.
Key preventive measures include:
- Thorough risk assessment – Avoiding unnecessary procedures, including elective cosmetic interventions, in keloid-prone patients.
- Minimal tension surgery – Reducing mechanical stress on the wound to prevent excessive fibroblast activation.
- Eversion of wound edges – Ensuring the wound edges are properly aligned to promote optimal healing.
- Limiting the number of sutures – Reducing the inflammatory response by minimising sutures and considering alternatives.
- Using non-suture closure techniques – Where appropriate, using skin glue or Steri-Strips instead of traditional sutures to decrease the risk of excessive scar formation.
Take home points
Paediatric keloid disorder occurs when the skin heals abnormally, resulting in thicker scars that can be itchy and limit movement.
As there is a lack of robust evidence surrounding its treatment, prevention is often better than cure.
References
Hypertrophic scars and keloids: A complete overview — DermNet [Internet]. DermNet®. DermNet; 2023 [cited 2024 Dec 8]. Available from: https://dermnetnz.org/topics/keloid-and-hypertrophic-scar
Ogawa R. The Most Current Algorithms for the Treatment and Prevention of Hypertrophic Scars and Keloids: A 2020 Update of the Algorithms Published 10Years Ago. Plastic and Reconstructive Surgery. 2022;149:e79–94.
Sun LM, Wang KH, Lee YC. Keloid Incidence in Asian Peo-ple and Its Comorbidity With Other Fibrosis-Related Diseases: A Nationwide Population-Based Study. Archives of Dermatological Research306. 2014;(9):803–8.
Yang YC, Cheng YW, Lai CS, Chen W. Prevalence of Child-hood Acne, Ephelides, Warts, Atopic Dermatitis, Psoriasis, Alopecia Areata and Keloid in Kaohsiung County, Taiwan: A Community-Based Clinical Survey. Journal of the European Academy of Dermatology and Venereology. 2007;21(5):643–9.
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Moustafa MF, Abdel-Fattah MA, Abdel-Fattah DC. Presumptive evidence of the effect of pregnancy estrogens on keloid growth. Case report. Plast Reconstr Surg [Internet]. 1975;56(4):450–3. Available from: http://dx.doi.org/10.1097/00006534-197510000- 00019
Chen Y, Gao J-H, Liu X-J, Yan X, Song M. Characteristics of occurrence for Han Chinese familial keloids. Burns [Internet]. 2006;32(8):1052–9. Available from: http://dx.doi.org/10.1016/j.burns.2006.04.014
Patel PA, Bailey JK, Yakuboff KP. Treatment outcomes for keloid scar management in the pediatric burn population. Burns [Internet]. 2012;38(5):767–71. Available from: http://dx.doi.org/10.1016/j.burns.2011.11.007
Leszczynski R, da Silva CA, Pinto ACPN, Kuczynski U, da Silva EM. Laser therapy for treating hypertrophic and keloid scars. Cochrane Database Syst Rev [Internet]. 2022;9(9):CD011642. Available from: http://dx.doi.org/10.1002/14651858.CD011642.pub2
