Scars are a normal part of healing. Sometimes the body lays down too much collagen while a wound closes, and the result is a raised, firm scar that sits above the surrounding skin. Those scars fall into two groups — keloids and hypertrophic scars. They look similar, but they behave differently, and that difference matters when it comes to treatment.
Keloids: scars that keep growing
A keloid is a thick, raised scar that spreads beyond the edges of the original wound. It can keep growing long after the skin underneath has healed, and it may be itchy or painful.
- Extends past the original injury
- Firm, rubbery texture
- Often red, pink, or darker than the surrounding skin
- May only appear months after the injury
- Can occur anywhere, but is most common on the upper chest, upper back, shoulders, ears and cheeks
Keloids are benign — they are not cancerous and they are not dangerous. What they affect is comfort and appearance.
Hypertrophic scars: raised but contained
A hypertrophic scar is also raised, but it stays within the boundary of the original wound. These are more common after surgical wounds, burns and other skin trauma, and they often settle by themselves over time.
- Confined to the original wound area
- Less aggressive than a keloid
- May fade and flatten on its own
- Generally easier to treat than a keloid
What causes them
Both are caused by an overproduction of collagen during healing. Why that happens in some people and not others is still not fully understood. Several things are known to influence it.
Genetics and skin type
Keloids are more common in people with darker skin tones, including those of African, Hispanic and Asian background. A family history raises the risk.
Hormones
Hormonal changes in childhood and puberty appear to affect how keloids form.
The type of injury
Keloids can appear after very minor trauma — acne, a piercing, a tattoo, an insect bite — and occasionally with no obvious injury at all. Wound infection and contact dermatitis may also play a part. Hypertrophic scars are more likely after surgery, burns or significant trauma.
Where the scar is
Keloids tend to form on the chest, upper back, ears, cheeks and shoulders. Hypertrophic scars can appear anywhere, most often along a surgical wound.
How they are diagnosed
A dermatologist can usually diagnose a keloid or hypertrophic scar by examining the skin. Occasionally a skin biopsy is needed to confirm the diagnosis or to rule out something else.
What treatment can and cannot do
This is worth being direct about, because it sets expectations for everything that follows.
What to expect from treatment
No treatment removes a scar completely or restores the skin to exactly how it was. There is almost always some minor change in the skin left behind. What treatment can do — often very effectively — is reduce the size, redness, itch and pain of a scar, and leave something smaller and far less noticeable.
Despite a wide range of available treatments, keloids and hypertrophic scars remain genuinely difficult to treat, and no single method suits every patient. Some scars need repeated or combined treatments. Some recur months or years later. Not every scar responds.
Two patterns hold up well in practice:
- Small keloids and hypertrophic scars under 1cm usually do well with intralesional steroid injections.
- Medium (1–2cm) and large (over 2cm) ones usually do well with intralesional cryosurgery.
- Keloids larger than 3cm may not be suitable for treatment at the clinic, and may need to be referred elsewhere, including abroad.
Timing matters more than almost anything else. The earlier a scar is treated, the better it tends to respond. Scars older than two years are considerably harder to shift.
The treatments available
Each of these has its own page explaining how it works, who it suits and what the recovery involves.
- Intralesional cryosurgery — freezing the scar from the inside out
- Intralesional steroid injections — first-line for small, recent scars
- Silicone sheets and gels — most useful early, to prevent a scar progressing
- Cryosurgery — surface freezing with liquid nitrogen
- Radiosurgical excision — removing the scar with radio waves
- Combination treatments — how these are used together
- Laser treatment — reduces redness and itch rather than size
- Imiquimod 5% cream — to reduce recurrence after removal
- Cosmetic camouflage — concealing what remains
- Superficial X-ray therapy — by referral
- Bleomycin and 5-FU injections — by referral
Surgery alone is not the answer
Cutting a keloid out on its own is not recommended. The recurrence rate is high, and the scar can grow back larger than it was. Excision is only used when it is followed by another treatment — cryosurgery, steroid injections, imiquimod cream or radiotherapy — to stop it returning.
Can they be prevented?
Not always, but the risk can be reduced.
- Avoid unnecessary skin trauma, particularly tattoos and piercings, if you know you are prone to keloids
- Treat acne early
- Use pressure earrings after ear piercings
- Apply silicone sheets or gels while a wound is healing
- Tell your surgeon beforehand if you have a history of keloids
Living with a keloid or hypertrophic scar
These scars are harmless, but that is not the same as being unimportant. They itch, they can hurt, and when they sit somewhere visible they affect how people feel about being seen.
Early intervention leads to better outcomes. With the right treatment, most small scars under 1cm and most medium scars of 1–2cm can be improved considerably, both in how they look and in how they feel.
Common questions
Can keloids go away on their own?
Keloids usually do not go away without treatment, and they may continue to grow over time. Hypertrophic scars are more likely to fade by themselves.
Is treatment painful?
Most treatments are well tolerated. Cryosurgery is carried out under local anaesthetic. Steroid injections cause brief discomfort.
How soon after an injury should treatment start?
As early as possible. This is particularly true for silicone sheets and steroid injections, both of which work best on scars that are still forming.