Scar tissue that feels firm or hard to the touch is often referred to as a keloid scar. Keloids are a type of raised scar that can form after injury, surgery, burns, acne, or sometimes even minor skin irritation. Unlike regular scars that soften and flatten over time, keloids continue to grow beyond the bounds of the original wound and do not regress on their own.
What causes keloids?
Doctors are not entirely sure what causes keloids to form, but research suggests they may be related to how a person’s skin heals after injury. When the skin is damaged, the body produces more collagen during the healing process. Collagen is a protein that provides structure and strength to tissues. In people prone to keloids, their cells produce too much collagen which leads to an overgrowth of tissue that extends beyond the original wound margins. This excess scar tissue grows raised above the skin surface and does not stop growing on its own like a regular scar. Keloids can range in size from very small to quite large.
While anyone can develop keloids, some factors that increase risk include:
- Age – Keloids are more common in younger people, especially those under 30 years old.
- Genetics – People with a family history of keloids are more likely to develop them.
- Skin type – Keloids occur more frequently in people with darker skin tones.
- Location – Areas like the chest, shoulders, upper back, and earlobes are more prone to keloids.
- Injury type – Keloids are more common after severe wounds or burns.
Signs and symptoms
The main signs and symptoms of keloids include:
- Raised, hardened scar tissue – The scar rises above the surrounding normal skin and feels rubbery or firm.
- Does not regress – Unlike regular scars, keloids do not flatten and fade over time. They continue to slowly enlarge.
- Grows beyond original wound – Keloids expand beyond the original wound margins and have an irregular shape.
- May be itchy – Some keloids are pruritic and cause itching sensations.
- Pink or purple color – Can be flesh-colored but often have a reddish-purple hue. The color may darken over time.
- Shiny surface – Keloids often have a smooth, shiny appearance compared to surrounding skin.
- Can cause pain – Some keloids are tender, painful, or sensitive.
Differences between keloids, hypertrophic scars, and regular scars
Keloids are often confused with hypertrophic scars and normal scars because they all involve overgrowth of collagen in injured skin. Here is a comparison:
| Type | Features |
|---|---|
| Keloid |
|
| Hypertrophic scar |
|
| Regular scar |
|
The main distinguishing feature of keloids is that they grow much larger than the original wound size. Hypertrophic scars and regular scars remain confined to the area of the original cut, burn, or incision.
Diagnosing keloids
Keloids are typically diagnosed through visual inspection and physical exam. The provider will look for the characteristic features of a keloid:
- Raised scar that feels rubbery and firm
- Grows beyond the margins of the original injury
- Does not improve over time
- May be reddish-purple in color
Your doctor will ask about your medical history, including any prior trauma, wounds, or family history of abnormal scarring. A skin biopsy may be done to confirm it is a keloid if the diagnosis is uncertain.
Treatment options
There are variety of treatments that can help improve the appearance and symptoms of keloids, although removing keloids completely is difficult:
Steroid injections
Corticosteroid injections is a common first-line treatment for keloids. The steroids help shrink the scar by suppressing inflammation and reducing collagen production. Multiple injections are often needed over time to flatten and soften the keloid.
Cryotherapy
Cryotherapy uses extreme cold from liquid nitrogen to damage the scar tissue and encourage new collagen growth. This helps reduce the keloid size when performed repeatedly over time.
Silicone gel sheeting
Custom-fitted silicone sheets are worn over the keloid to compress and flatten the scar while allowing oxygen to penetrate. Using them for 12+ hours a day often gradually improves keloid appearance.
Radiation therapy
Various types of radiation can help prevent recurrence after surgical keloid removal by slowing down cell activity. Radiation is often used along with other treatments.
Laser treatment
Laser resurfacing removes outer layers of the keloid to improve texture and make it less raised. Lasers may also disrupt blood vessels and collagen fibers in the scar.
Surgery
Surgical removal of the keloid is frequently followed by other treatments like radiation or steroid injections to prevent the keloid coming back. Surgery alone has a high recurrence rate.
Compression
Compression bandages, tape, or garments worn over keloids can help flatten them over time. This works best on smaller keloids.
Interferon injections
Interferons inhibit collagen production and may cause scar tissue breakdown. Like steroids, multiple injections into the scar may be needed.
5-FU injections
5-Fluorouracil (5-FU) is a chemotherapy drug that is injected to destroy excessive fibroblast cells in keloids. This can help shrink the scar when used repeatedly.
Bleomycin injections
Bleomycin is a chemotherapy medicine that can be injected into keloids to stunt their growth. It’s typically used along with triamcinolone steroid injections.
Imiquimod cream
Imiquimod stimulates the immune system and may help decrease collagen production when applied topically to keloids over time.
Prevention
It can be difficult to prevent keloids altogether, especially in those with a genetic predisposition. However, the following tips may reduce the risk of developing keloids:
- Avoid piercings and elective procedures in areas prone to keloids like earlobes, shoulders, central chest.
- After surgery, follow wound care instructions closely to minimize scarring.
- Treat even minor skin injuries with care to avoid excessive collagen formation during healing.
- Use silicone gel sheets or liquid after surgery to protect incisions.
- Avoid unnecessary trauma such as scratches, burns, cuts to sensitive areas when possible.
- Consult a dermatologist at the first sign of an abnormal appearing scar.
Conclusion
Keloids are a type of prominent, difficult-to-treat raised scars that grow larger than the original injury site. They are caused by excess collagen formation during wound healing in genetically prone individuals. Keloids can often be distinguished from regular scars and hypertrophic scars by their tendency to continue growing, extend beyond original wound margins, and not regress over time. While keloids can’t always be prevented, a combination of treatments like steroid injections, cryotherapy, radiation, and surgery can often improve their appearance and associated symptoms when they do occur.