Are you dealing with a scar that seems to be larger and more unsightly than usual? It could be a keloid scar. When it comes to keloid vs hypertrophic scars, there are many major differences.
Let’s take a closer look at scar tissue, the role of collagen synthesis in scars, how these two scar types differ from each other – and what you can do about them.
To best understand any type of scarring, it’s best to understand what a scar actually is and how and why it forms. If you’ve been wondering about a particular scar on your body, you’ve come to the right place.
What is a Scar?
A scar arises when your skin repairs a wound, like a cut or burn. To repair this wound, your skin cells produce a fibrous extracellular matrix of connective granulation tissue. In short? This connective tissue is thicker and stronger than normal tissue.
This thick tissue is made up of collagen fibers. And these collagen fibers help bridge and strengthen the wounded area after protective epithelial tissue has filled it in a little.1
Now, these fibers might be strong, but they’re not very elastic. They can form small bundles known as scar tissue.
And so, after a wound has gone through the healing process, you can be left with scar tissue. This scar tissue has quite a different texture from the surrounding tissue. And because scar tissue has no hair follicles, there will be a lack of hair growth in this area.
What Causes Keloidal Scarring?
When a wound is successfully bridged by fibers, a regular scar forms and fibroblasts put down their tools, stopping their work. But with keloid scars, collagen production keeps on going even after the wound is closed.
This is why keloid scars appear as raised, red, bumpy nodules. What you’re left with is excessive scar tissue above the surface of the skin, and often over a much larger area than the actual wound.
Some people are more susceptible to keloid scars, including those with darker skin tones. And keloid scars are more likely to form on certain areas of the body. The upper chest, upper back, shoulders, and cheeks (acne scars), seem to be more susceptible to keloid scarring.
The scarred skin may be itchy and painful. It can also be psychologically upsetting, because keloids may be disfiguring.2
What is a Hypertrophic Scar?
Hypertrophic scars are more common than keloids. They share some similarities, but they aren’t usually as big and don’t extend too far past the actual wound. The collagen bundles are much finer and better organized, so they don’t become as raised as keloid scars. They can also fade over time.
Hypertrophic scars can occur anywhere on the body, including over joints like elbows and knees. This can be problematic if it causes contractures – a tightening of the skin in that region. They can also occur when there’s a lot of tension around a wound.
Like keloids, hypertrophic scars are more common in darker skin types.3
Keloid vs Hypertrophic Scar: In Simple Terms
Both a hypertrophic scar and keloid scar are considered abnormal scarring of the dermis (skin).
- Are commonly raised more than 4 mm from the skin’s surface
- Lesions generally grow wider than the boundaries of a wound
- May continue to grow over time
- Are seen predominantly on the shoulders, cheeks, upper back, and chest
- Appear after three months or so
- Have a high recurrence rate after treatment
- Rarely become raised more than 4 mm above the skin
- Are generally neater and cover only the wound circumference
- Can develop anywhere on the body
- Often fade somewhat over time
- Appear within one month
What’s the Best Way to Manage these Types of Scars?
The treatment for keloids and hypertrophic scars is difficult. There is no one proven scar management solution. But there are some treatment options that doctors and dermatologists may commonly suggest to patients.
Though both types of scars are often treated the same way, hypertrophic scars may respond better to treatment. Keloids, on the other hand, have a high rate of recurrence.
Here are some of the ways keloid and hypertrophic scars are managed:
Silicone gel sheeting – Silicone gel elastomer sheets are applied as soon as the wound has healed. They’re thought to work by increasing temperature, hydration, and oxygen tension to the scar, helping it to soften or flatten.
Pressure and massage therapy – Massaging and applying pressure to the scar may help to weaken the scar tissue and improve the scar’s appearance.
Intralesional triamcinolone corticosteroid injections – These injections narrow blood vessels, helping to flatten and soften the scar.
Laser treatments – These treatments burn and flatten elevated scars. They may help fade a scar’s red and pink-colored pigments.
Cryotherapy treatment – Cryotherapy freezes off small lesions and helps to soften scars.
Excision surgery – Unfortunately, even if a scar excision looks successful, keloid-type scars may come back. For this reason, doctors may follow excision surgery with corticosteroid injections, silicone sheeting, and/or pulsed dye laser.
Radiation therapy – Physicians tend to reserve radiation as a last resort for severe cases of keloids. The keloid is surgically removed, then a doctor uses an electron beam or orthovoltage radiation immediately afterward. This can be quite effective but also expensive.4,5
How does Dermal Cryotherapy Work?
Traditionally, clinical cryotherapy treatment involves the use of liquid nitrogen to remove tissue through the process of freezing. It’s popular for freezing off warts and other small lesions.
In the treatment of scars, cryotherapy has become popular for softening keloids and hypertrophic scars so that intralesional injections may work better. Cryotherapy may be used for freezing off small keloids or hypertrophic scars caused by such things as acne.6
Note: This type of acne scar should not be confused with atrophic scars, an indented scar that heals below the normal layer of skin tissue.
The Future: Stem Cell Treatments?
Treatments involving stem cells are also under exploration in clinical studies. As it turns out, endothelial cells in blood vessels may be able to help stimulate healing without forming unhealthy scar tissue (like keloid scars).7
Clinical research is also being done on something called tumor necrosis factor-alpha, a naturally occurring substance in the body that usually causes irritation. TNF-alpha may be able to help keloid scarring.8
Can You Prevent Hypertrophic or Keloid Scarring?
If you know that you’re susceptible to these types of scars, especially keloids, try to avoid any kind of injury to your skin, including piercings and tattoos.
Research has shown that hypertrophic scars are exceptionally common after surgery and after burn injuries.
Talking to your surgeon about your history with keloid or hypertrophic scarring can also help. They may be able to help lessen the effects by ensuring that surgical incisions are along skin tension lines.9
Tips to Help Avoid These Scars
If you’ve suffered a minor injury and you’re prone to hypertrophic or keloid scarring:
- Cover the wound with a thin layer of petroleum jelly and a nonstick bandage. Tape the bandage so there’s pressure on the wound.
- Wash the wound with soap and water every day and change the bandage.
- Apply silicone gel bandages daily, after the wound has healed. These should be kept on the skin for 12-24 hours a day, for up to three months. This is because it takes three months for a keloid to grow.
Note: Keloids are common on tiny ear-piercing wounds, but they can leave some not-so-tiny scars. If you do get your ears pierced, there are pressure earrings available (known as Zimmer splints) that have been designed precisely for warding off keloids.10
Hypertrophic or Keloid Scars: Know the Difference
There’s no denying that scars can be disheartening and even emotionally debilitating. No one really knows why they form in some people and not others. There’s no solid scientific evidence that these types of scars are genetic, but it is fairly common to get them if a parent has them.
If you’re hoping to improve the appearance of hypertrophic or keloid scars, or prevent a recurrence, seeing a doctor for treatment early is essential. As soon as a wound is healed, talk to your doctor, dermatologist, or surgeon about your options if you’re concerned about keloid or hypertrophic scars.
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