A keloid is a raised, firm scar that grows beyond the edges of the original wound and doesn’t shrink on its own. Unlike a normal scar, which stays within the boundaries of an injury and gradually fades, a keloid keeps expanding into surrounding healthy skin, sometimes months or even years after the initial wound has healed. Keloids can appear after something as minor as an ear piercing or acne breakout, and they often cause persistent itching or pain.
How Keloids Form
Normal wound healing involves your body producing collagen, a structural protein that knits damaged skin back together. Once the wound closes, collagen production slows down and the scar gradually flattens. In keloid formation, that process never properly shuts off. Your body keeps producing collagen long after the wound has healed, and the excess tissue builds up into a dense, raised mass that spreads past the original injury site.
The collagen in keloids is also different in composition. Keloid tissue has a dramatically elevated ratio of one type of structural collagen to another, roughly four times higher than what’s found in normal skin. On top of that, the body breaks down less of this newly made collagen than it normally would. The combination of overproduction and under-degradation is what drives the progressive, sometimes relentless growth that makes keloids so difficult to treat.
Common Triggers and Locations
Almost any skin injury can trigger a keloid in someone who is prone to them. The most common causes include surgical incisions, ear and body piercings, acne, burns, chickenpox, vaccination sites, and even minor scratches. In rare cases, keloids form spontaneously without any identifiable wound.
Certain areas of the body are more susceptible. The earlobes, chest, shoulders, and upper back are classic sites, likely because of the higher skin tension in those regions. Keloids on the earlobes after piercing are especially common and tend to form smooth, dome-shaped growths that can become quite large.
What Keloids Feel Like
Keloids aren’t just a cosmetic issue. In a controlled study of keloid patients, 86% experienced itching and 46% reported pain related to their keloids. These sensations aren’t random. The dense, abnormal collagen in a keloid physically compresses small nerve fibers inside the scar, causing pain that tends to be worst in the center. The itching, by contrast, comes from regenerating nerve endings at the outer edges of the keloid, which is why many people notice the itch around the borders rather than in the middle.
Beyond pain and itch, keloids can restrict movement if they form over a joint, and their appearance causes significant emotional distress for many people. Large or visible keloids commonly affect self-esteem and quality of life.
Keloids vs. Hypertrophic Scars
These two types of raised scars are frequently confused, but the distinction matters because they behave differently and respond to different treatments. The defining difference: a hypertrophic scar stays within the boundaries of the original wound, while a keloid spreads beyond them. If a raised scar hasn’t crossed past the edges of your original injury, it is not a keloid by definition.
Hypertrophic scars are also more common and tend to improve over time, often flattening on their own within a year or two. Keloids do not regress spontaneously. They either stay the same size or continue growing, and they’re far more likely to recur after treatment.
Who Gets Keloids
Keloids can affect anyone, but prevalence varies dramatically across populations. Reported rates range from 0.09% in England to 16% in the Democratic Republic of Congo. A UK study of nearly 1,000 patients found excessive scarring in 2.4% of Black patients, 1.1% of Asian patients, and 0.4% of white patients. People with darker skin tones are consistently overrepresented in keloid populations relative to their share of the general population.
Family history plays a significant role. If a close relative develops keloids, your risk is substantially higher. Keloids most commonly appear between ages 10 and 30, and they’re rare in very young children and older adults.
First-Line Treatment Options
Current evidence supports silicone gel or sheeting combined with corticosteroid injections as the first-line approach for keloids. Silicone sheets are worn against the scar for 8 to 10 hours at a time, removed to let the skin breathe, then reapplied. They work by hydrating the scar tissue and creating gentle, sustained pressure. Corticosteroid injections are delivered directly into the keloid every few weeks, softening and flattening the tissue over time. Response rates to corticosteroid injections range from 50% to 100%, though side effects can include skin thinning, small blood vessel dilation, and lightening of the skin at the injection site.
When corticosteroid injections alone aren’t enough, combining them with a chemotherapy-derived medication that blocks abnormal cell growth can improve results. One combination therapy achieved an average 92% reduction in lesion size compared to 73% with steroid injections alone. Other injectable options that slow collagen production or trigger cell death in the scar tissue can also be considered, with injections typically spaced two to four weeks apart.
Surgery and Recurrence
Surgical removal of a keloid sounds straightforward, but it comes with a significant catch: when surgery is performed alone, the keloid grows back 50% to 80% of the time. That’s because the same wound-healing abnormality that created the keloid in the first place is triggered again by the surgery itself.
To lower this risk, surgeons typically combine excision with radiation therapy delivered in the days immediately following the procedure. This combination brings recurrence rates down considerably, with some studies reporting rates as low as 6.7% when surgery is paired with specialized suturing techniques and radiation. However, results vary widely across studies, with other groups reporting recurrence rates of 27% to 33% even with radiation. For this reason, surgery with radiation is generally reserved for keloids that haven’t responded to less invasive treatments.
Laser therapy is another option, often used alongside corticosteroid injections or topical steroids to improve how deeply medication penetrates the scar tissue.
Preventing Keloids
If you know you’re prone to keloids, the most effective prevention strategy is avoiding unnecessary skin trauma. That means skipping elective piercings and cosmetic procedures on high-risk areas like the earlobes, chest, and shoulders. When surgery is unavoidable, applying silicone sheeting to the healing wound and starting corticosteroid injections early can reduce the chance of keloid formation. Keeping wounds clean, minimizing tension on healing skin, and avoiding picking at scabs all help lower risk.
For people who have already had one keloid, the likelihood of developing another after any new skin injury is high. Discussing preventive measures with a dermatologist before any planned procedure, even something as routine as a mole removal, is worth the extra step.