When body tissue is damaged by a physical injury, a scar may form as the wound heals.
At first, scars can be red and raised. As the injury heals over time, the scar will become flatter and paler.
Tension around the wound can lead to a hypertrophic scar. These are thick and red and last for several years. In this article, we look at ways in which these scars can be treated, prevented, and reduced.
Hypertrophic scars occur when there is a lot of tension around a healing wound. These scars are thick and raised, and often red in color. They may remain like this for several years.
Hypertrophic scars are the result of an imbalance in collagen at the site of the wound.
Characteristics of a hypertrophic scar include:
- restricting movement, as the skin is no longer as flexible
- forming within the boundaries of the original wound
- creating healing tissue that is thicker than usual
- being red and raised to start with but becoming flatter and paler over time
Hypertrophic scars are not to be confused with keloids, although they do have some similar characteristics.
Keloids are reddish nodules that develop, as gristle-like connective tissue forms to heal a wound. A keloid continues to form even after the wound has healed, resulting in a large mound of scar tissue.
The American Osteopathic College of Dermatology estimate that keloids affect only around 10 percent of people, whereas hypertrophic scars are more common.
Hypertrophic scars affect men and women from any racial group equally, although people between the ages of 10 and 30 years old are more likely to be affected. This is believed to be because young people have more elasticity in their skin and produce collagen at a higher rate.
Both keloids and hypertrophic scars can be painful and itchy. They generally occur on the upper body, upper arms, shoulders, neck, or earlobes.
Often hypertrophic scars settle over time on their own, but some treatments can help the process.
Silicone gel sheeting has been used in the treatment of hypertrophic scars since the early 1980s.
This treatment is best used at the very early stage of scar development. Pads are placed directly on the scar for 23 of the 24 hours in a day for between 6 and 12 months.
It is believed that the silicone builds up a reservoir of water under the pad that helps keep the scar hydrated. This increased hydration can help prevent a worse hypertrophic scar from forming.
This treatment works by applying compression to the wound. It is often used for burn treatment. Pressure dressings are especially useful if wounds take longer than 10 to 14 days to heal, or after skin grafting.
It has been claimed that the use of high pressure, elastic dressings can reduce the formation of hypertrophic scars by between 60 and 85 percent.
Pressure dressings work by limiting the blood, oxygen, and nutrients to a wound, which reduces the rate of collagen production.
Cortisone or steroid injections are the first-line treatment for keloids. They can also be used to treat hypertrophic scars. The injections are repeated every few weeks.
Between 50 and 100 percent of people notice an improvement after cortisone injections, and often hypertrophic scars will fade completely after this treatment.
However, there is also a 9 to 50 percent recurrence rate. Side effects can include darkening skin of the treated and surrounding area.
Hypertrophic scars can increase in size for the first 3 to 6 months and then begin to regress. For this reason, surgery is not usually necessary.
However, if the hypertrophic scars are impeding movement due to being at a joint, or they are causing excessive tension in the surrounding tissue, then surgery may be an option.
Other treatments for hypertrophic scars include:
- Cryotherapy: This combination of liquid nitrogen with steroid injections has been shown to be effective for keloids but is not often used for hypertrophic scars.
- Creams and oils: Options include onion extract, heparin gel, and bleomycin.
- Superficial X-ray treatment: This treatment may be used soon after surgery but is uncommon.
- Laser treatment: Laser treatment can improve skin texture and color but does not always flatten a hypertrophic scar.
Research suggests that hypertrophic scars are common after burn injuries with between 30 and 91 percent of reported hypertrophic scars following a burn.
Hypertrophic scars can also follow many other injuries, such as accidental trauma or piercings, as well as surgery.
Avoiding any unnecessary skin surgery will limit the chance of getting a hypertrophic scar, as the incidence rate after surgery is around 40 to 94 percent.
When skin surgery is unavoidable, the surgeon will try to ensure that surgical lines are along the skin tension lines whenever possible. The use of silicone gels and sheets for several months after an operation may also help reduce scarring.
Hypertrophic scars will sometimes occur after inflammation from a skin condition, including acne and chickenpox. Prompt and effective treatment for these illnesses can help prevent hypertrophic scars from forming.
Hypertrophic scars are benign and not harmful to a person's general health. They do not develop into skin cancer.
A hypertrophic scar will often regress completely between 6 months and 3 years after it first appears.
Around 75 percent of people with hypertrophic scars said their biggest concern was how the scar appeared, rather than how it affected their health.
It is important to note that different treatments may also have side effects, so if the scar is not harmful, the best action may be no action.
If a person is anxious about the appearance of a hypertrophic scar, however, they should consult a doctor to discuss their treatment options.
Treatment will be determined depending on the site, size, thickness, and spread of the hypertrophic scar.