By the WoundSource Editors
After an injury or surgery, the body responds by forming scar tissue. Scar formation is a normal part of the wound healing process, but not all scars are the same. Some scars form in only the superficial epidermal layers, whereas others encompass deeper subdermal layers, involving nerves and tendons.1
The process of scar formation is the result of myofibroblast cells forming new collagen fibers to repair a wound. Active scars may manifest as firm, raised, reddish, and thick. In the first four to six weeks of healing, scars often become larger and redder, but this is a normal phase of healing. Some scars are highly sensitive, and scar tissue may limit range of motion depending on location. It can take up to two years for a scar to heal fully and blend into the surrounding skin.
Although most scars eventually become flat and pale, in some cases the body produces an excess of collagen, resulting in a raised type of scar.
Review: Keloid Management: A Retrospective Case Review on a New Approach
When myofibroblasts overproduce collagen during the healing process, a hypertrophic scar may form. This is more common in cases where a wound is infected, inflamed, or subject to a high level of tension, such as an injury over a joint. Burn injuries are prone to hypertrophy, but even mild injuries such as piercings, cuts, and acne can result in these raised scars. Hypertrophic scars are more common in young people and those with higher levels of pigment in their skin. Hypertrophic scars can develop on any part of the body, they can be red or pink, and they are raised less than four millimeters.
Sometimes confused with hypertrophic scars, keloids are far more noticeable because they are often considerably larger than the original wound. Keloids are more likely to develop on the ears, shoulders, chest, neck, and back. The risk factors for developing keloids are not fully understood, but there appears to be a genetic predisposition.2 A family history of keloid scars is a strong indicator of risk. Persons with darker skin are at a higher risk of keloid scarring. This risk may reflect abnormalities in melanocyte production3 or the presence of stress hormones4 stimulating overproduction of collagen. Unlike hypertrophic scars, keloids are pink to purple, may grow over time, and are raised more than four millimeters from the skin.
Topical Treatments for Hypertrophic and Keloid Scars
Although hypertrophic and keloid scars are harmless, they can be itchy or sensitive. Despite the benign nature of these scars, some individuals may seek treatment to minimize scar appearance.
Injection of corticosteroid agents into hypertrophic and keloid scars is the treatment recommended by most dermatologists. These agents help to reduce scarring by breaking up collagen fiber bonds. The anti-inflammatory effects of the corticosteroids may also reduce itching, redness, and sensitivity.
Also known as cryosurgery, cryotherapy uses the application of liquid nitrogen to freeze the superficial layers of the scar, thereby reducing its size.
Although dermabrasion is not recommended for keloids, it can help to manage hypertrophic scars over large areas. After injecting a local anesthetic, a clinician uses a tool to remove the surface of the scar. This treatment does not remove a scar entirely but improves its color and texture so that the scar blends more with surrounding skin.
In laser therapy, a scar is exposed to a high-energy beam of light that resurfaces the scar by burning surface cells and stimulating a healing and exfoliation response. This treatment can flatten elevated scars and reduce hyperpigmentation. Laser therapy is generally more effective on newer scars.5
Hypertrophic scars sometimes respond well to massage. This treatment is standard in rehabilitation centers for scars and burns,6 and it may help to reduce sensitivity and pruritus while smoothing the surface of the scar.
By reducing the delivery of blood, nutrients, and oxygen to a scar, pressure garments can relieve pain and itching associated with hypertrophic burn scars. Compression is a first-line therapy for reducing collagen synthesis, but this treatment is generally suitable only on the trunk and non-flexion areas.7
Silicone Pads or Sheets
Silicone gels, pads, and sheets are over-the-counter treatments that are most effective on new and active scars.8 They must be applied at least once a day and usually must be used on a continuous basis for several months.
Although hypertrophic and keloid scars are not a cause for concern, they may be aesthetically undesirable or physically uncomfortable. There are a number of topical treatments that can be administered at home or by a dermatologist to improve the appearance and sensation of these abnormal scars.9
1. Grishkevich VM. Ankle dorsiflexion postburn scar contractures: anatomy and reconstructive techniques. Burns. 2012;38(6):882-888.
2. Marneros AG, Norris JE, Watanabe S, Reichenberger E, Olsen BR. Genome scans provide evidence for keloid susceptibility loci on chromosomes 2q23 and 7p11. J Invest Dermatol. 2004;122(5):1126-1132.
3. Luo L, Shi Y, Zhou Q, Xu S, Lei T. Insufficient expression of the melanocortin-1 receptor by human dermal fibroblasts contributes to excess collagen synthesis in keloid scars. Exp Dermatol, 2013;22:764-766. doi:10.1111/exd.12250.
4. Hochman B, Isoldi FC, Furtado F, Ferreira LM. New approach to the understanding of keloid: psychoneuroimmune-endocrine aspects. Clin Cosmet Investig Dermatol. 2015;8:67-73. doi:10.2147/CCID.S49195.
5. Bouzari N, Davis SC, Nouri, K. Laser treatment of keloids and hypertrophic scars. Int J Dermatol. 2007;46:80-88. doi:10.1111/j.1365-4632.2007.03104.x.
6. Roques C. Massage applied to scars. Wound Repair Regen. 2002;10(2):126-128.
7. Reno F, Grazianetti P, Cannas M. Effects of mechanical compression on hypertrophic scars: prostaglandin E2 release. Burns. 2001;27:215-218.
8. Gold MH. A controlled clinical trial of topical silicone gel sheeting in the treatment of hypertrophic scars and keloids. J Am Acad Dermatol. 1994;30:506-507.
9. Arno AI, Gauglitz GG, Barret JP, Jeschke MG. Up-to-date approach to manage keloids and hypertrophic scars: a useful guide. Burns. 2014;40(7):1255-1266. doi:10.1016/j.burns.2014.02.011.
The views and opinions expressed in this blog are solely those of the author, and do not represent the views of WoundSource, Kestrel Health Information, Inc., its affiliates, or subsidiary companies.