Introduction
Scarring is an inevitable consequence of tissue injury, a testament to the remarkable resilience of the human body's healing capabilities. When the skin undergoes trauma, such as surgery, burns or other injuries, the body's natural response is to heal the affected area. Yet, not all scars are created equal. In some cases, this healing process can result in the formation of abnormal scars, such as keloids and hypertrophic scars.
Keloids and hypertrophic scars deviate from the ordinary course of wound healing, presenting unique challenges for affected individuals and healthcare professionals. These scars are not only a cosmetic concern but can also cause discomfort and psychological distress. In this era of advancing medical knowledge and innovative therapies, the management of keloids and hypertrophic scars post-injury has evolved into a multifaceted endeavour, encompassing a range of preventive, therapeutic, and aesthetic strategies.
This article embarks on a journey through the complex terrain of scar management, shedding light on the intricacies of these aberrant scars and offering insights into a comprehensive approach that combines both conventional and emerging techniques. As we delve into the depths of this evolving field, we explore the pathogenesis, clinical presentation, and treatment modalities that form the foundation of effective scar management, ultimately aiming to empower individuals with the knowledge and tools to regain confidence and restore the integrity of their skin.1
The process of scar formation and tissue healing
Scar formation is an integral component of the body's innate healing mechanism following tissue injury. This process involves a series of complex events that culminate in the production and remodelling of collagen, resulting in the gradual maturation of the scar. Understanding the dynamics of scar formation is crucial in the fields of medicine and biology, as it provides insights into the body's response to tissue damage and the eventual resolution of the wound. Below are the stages of wound healing:2
Collagen production and initial scar formation
When the skin is wounded, the structural integrity of the underlying tissues is compromised, leading to the release of collagen (a fibrous protein integral to the wound-healing process). Collagen deposition at the site of injury serves the dual purpose of healing the wound and fortifying the damaged tissue. In this initial phase, the scar may exhibit a raised and lumpy appearance as collagen accumulates.
Ongoing collagen synthesis and vascular changes
The healing process continues as the synthesis of collagen persists for several months after the initial injury. Simultaneously, there is an increase in the blood supply to the wounded area (vascularisation). Vascularisation contributes to the elevation and uneven texture of the scar, further emphasising the active nature of the healing process.
Scar maturation
With time, a gradual shift occurs in the composition of the scar tissue. Some of the excess collagen is broken down at the wound site, and the heightened blood supply gradually diminishes. These changes lead to a smoother and softer texture of the scar, indicative of its maturation phase. During this period, the scar begins to blend more seamlessly with the surrounding healthy tissue.
Scar fading and long-term persistence
While scars are generally considered permanent, they often tend to fade over time. This fading process typically extends over two years following the initial injury. After this timeframe, it is unlikely that further significant fading will occur. Despite their permanence, scars can become less noticeable and may eventually harmonise with the surrounding skin.
Understanding keloids and hypertrophic scars
Keloids and hypertrophic scars are both types of abnormal scars that develop as a result of an overproduction of collagen during the body's wound-healing process. While they share some similarities, they have distinct characteristics:
Hypertrophic scars
Hypertrophic scars are raised and thickened but remain within the boundaries of the original wound. They usually develop within weeks of the injury and tend to improve naturally over time. Hypertrophic scars do not have a strong tendency to recur after removal.3
Clinical presentation
Hypertrophic scars typically have a red or pink colouration and can be firm to the touch. They are often characterised by their raised and thickened appearance, which can make them aesthetically noticeable.4
Location
These scars are commonly found on areas of the body where there is increased tension or movement, such as the chest, shoulders, ear lobes, and upper back.
Regression
Unlike keloid scars, hypertrophic scars may undergo some degree of regression over time. They may become less raised and less red, eventually blending in better with the surrounding skin.5
Pathogenesis
The precise mechanisms behind hypertrophic scar formation are not fully understood but are believed to involve a combination of genetic predisposition, mechanical tension on the wound, and aberrant wound healing responses.5
Keloids
Keloids are also raised and thickened but often extend beyond the borders of the original injury. Unlike hypertrophic scars, they have a tendency to recur after removal and can continue growing over time. Keloids are more common in individuals with darker skin tones and are believed to have a genetic predisposition. They can be itchy and painful and may affect a person's self-esteem.1
Clinical presentation
Keloids are typically firm to the touch and have a pink, red, or dark brown colouration. They can vary in size and shape but generally extend beyond the margins of the original wound. Keloids can be itchy and may cause discomfort or pain in some cases.6
Common locations
Keloids can develop on any part of the body but are often found in areas with high tension or movement, such as the chest, shoulders, earlobes, and upper back. They can also occur after surgical procedures, injury, or even spontaneously.4
Predisposition
Keloids are more common in certain populations, such as in individuals with darker skin tones and people with a family history of keloid formation. Genetic factors are believed to play a role in an individual's predisposition to keloid scarring.5,6
Pathogenesis
The exact cause of keloid formation is not fully understood, but it is thought to involve a combination of genetic, environmental, and biochemical factors. Aberrant signalling pathways, inflammation, and altered collagen metabolism are some of the mechanisms believed to contribute to keloid formation.6
Managing keloids and hypertrophic scars
The management of keloids and hypertrophic scars requires a comprehensive approach that addresses both the physical and psychological aspects of scar formation. In most cases, complete scar removal is not possible. However, most scars will fade away eventually. Below are some effective strategies on how to improve the general appearance of scars:
Silicone gel sheets
Silicone gel sheets are widely used for scar management. They create a protective barrier over the scar, helping to flatten and soften its appearance. Studies have shown their efficacy in improving the texture and colour of scars over time.3
Corticosteroid injections
Intralesional corticosteroid injections are a common treatment for reducing the size and redness of keloids and hypertrophic scars. These injections work by suppressing collagen production and reducing inflammation.6 Multiple sessions may be needed for optimal results.
Pressure therapy
Pressure garments or dressings can help prevent the excessive production of collagen, thereby reducing the risk of hypertrophic scar formation. These garments apply controlled pressure to the scar, flattening it and improving its appearance.7
Laser therapy
Laser treatments, such as pulsed dye laser (PDL) and fractional laser therapy, are used to target blood vessels and collagen in scars. PDL can help reduce redness, while fractional laser therapy improves texture and promotes collagen remodelling.8
Surgical excision
Surgical removal of keloids is an option for some patients, although there's a risk of recurrence. Combining surgery with other treatments like corticosteroid injections or radiation therapy can improve outcomes.9
Radiation therapy
Radiation therapy after surgical excision has shown promise in reducing keloid recurrence rates.10 However, its use is often reserved for cases where other treatments have failed.
Summary
The formation of keloids and hypertrophic scars post-injury can be a distressing experience, affecting both physical and emotional well-being. However, with advances in scar management techniques, there are effective strategies available to help individuals mitigate the impact of these scars. Individuals need to consult expert healthcare professionals to determine the most suitable scar management plan based on their unique needs and scar characteristics.
References
- Carswell L, Borger J. Hypertrophic Scarring Keloids. [Updated 2023 Aug 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK537058/
- Chen, L. et al. (2018) ‘The clinical dynamic changes of macrophage phenotype and function in different stages of human wound healing and hypertrophic scar formation’, International Wound Journal, 16(2), pp. 360–369. doi:10.1111/iwj.13041. Available from: https://onlinelibrary.wiley.com/doi/full/10.1111/iwj.13041
- Mustoe TA, Cooter RD, Gold MH, et al. (2002) International clinical recommendations on scar management. Plast Reconstr Surg, 110(2), 560-571.doi:10.1097/00006534-200208000-0003 https://journals.lww.com/plasreconsurg/abstract/2002/08000/international_clinical_recommendations_on_scar.31.aspx
- Bock O, Schmid-Ott G, Malewski P, et al. (2006) Quality of life of patients with keloid and hypertrophic scarring. Archives of Dermatological Research, 297(10),433-438.doi:10.1007/s00403-005-0629-4 https://link.springer.com/article/10.1007/s00403-006-0651-7
- Gauglitz GG, Korting HC, Pavicic T, et al. (2011) Hypertrophic Scarring and Keloids: Pathomechanisms and Current and Emerging Treatment Strategies. Molecular Medicine, 17(1-2), 113-125. doi: 10.2119/molmed.2009.00153 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3022978/
- Berman B, Maderal A, Raphael B. (2017) Keloids and Hypertrophic Scars: Pathophysiology, Classification, and Treatment. Dermatologic Surgery, 43(Suppl1),S3-S18.doi:10.1097/DSS.0000000000000925 https://journals.lww.com/dermatologicsurgery/abstract/2017/01001/keloids_and_hypertrophic_scars__pathophysiology,.2.aspx
- Yuan B, Upton Z, Leavesley D, Fan C, Wang X-Q. Vascular and Collagen Target: A Rational Approach to Hypertrophic Scar Management. Adv Wound Care (NewRochelle) 2023;12:38–55. https://doi.org/10.1089/wound.2020.1348.
- Annabathula A, Sekar CS, Srinivas CR. Fractional Carbon Dioxide, Long Pulse Nd:YAG and Pulsed Dye Laser in the Management of Keloids. Journal of Cutaneous and Aesthetic Surgery 2017;10:76. https://doi.org/10.4103/JCAS.JCAS_136_16.
- Ogawa R. Keloid and Hypertrophic Scars Are the Result of Chronic Inflammation in the Reticular Dermis. Int J Mol Sci 2017;18:606. https://doi.org/10.3390/ijms18030606.
- Zainib M, Amin NP. Radiation Therapy in the Treatment of Keloids. StatPearls, Treasure Island (FL): StatPearls Publishing; 2023. https://www.ncbi.nlm.nih.gov/books/NBK499973/