Scars and Keloids: Types, Who Is Prone, Treatment Options and When to See a Physician

What is a scar, and why does everyone scar differently?

After every injury that reaches its middle layer (the dermis), the skin repairs itself with new tissue made up largely of collagen. This repair tissue is a scar. Anything that injures the skin, such as a cut, a burn, surgery, a spot, chickenpox, a vaccination, a piercing or a tattoo, can leave a scar.

How a scar will look is determined jointly by the depth and site of the wound, whether the wound is stretched during healing, whether infection develops, age, skin colour and inherited predisposition. A scar takes months to mature; fading and flattening can take two years or longer. For this reason, making an early judgement about the final appearance of a new scar can be misleading.

What are the types of scar?

Depressed scars after acne are a separate subject and are not covered in detail in this article; for their types and the options, see the article “Acne Scars”. For line-shaped scars that appear with pregnancy or changes in weight, the article “Stretch Marks (Striae)” offers guidance.

What is the difference between a hypertrophic scar and a keloid?

Both are raised scars and may look alike at first glance; however, they behave differently. A hypertrophic scar stays within the boundary drawn by the wound and mostly regresses on its own over time. A keloid, on the other hand, spreads into healthy skin, can become much larger than the original wound and does not shrink on its own.

• A keloid may itch, prickle or hurt while it is growing; once growth stops, these complaints mostly decrease.
• Its colour may be close to skin colour, pink, red, purple or darker than the surrounding skin.
• On the earlobe it is mostly a round, firm lump; on the chest and shoulder it tends to spread across the skin.
• If it is over or near a joint it can make movement difficult.
• A keloid is not contagious and does not turn into cancer.

The distinction is not always easy; whether a scar is hypertrophic or a keloid is decided by examination. The distinction matters because the treatment plan and the risk of recurrence differ.

Who is prone to keloids?

A keloid can develop in anyone; however, in some people the likelihood is markedly higher:

• People who have had a keloid before: this is the strongest warning sign.
• Family history: according to the American Academy of Dermatology, somewhere between about a third and a half of people with a keloid have at least one blood relative who also has keloids.
• Skin colour: the risk is highest in Black people; keloids are also more common in people with darker skin of Asian, Latin American and Mediterranean origin than in those with fair skin.
• Age: they appear more often between puberty and the thirties.
• Pregnancy: the likelihood of developing a keloid has been reported to increase during this period.
• Area: the front of the chest, the shoulders, the upper back, the earlobe and ear cartilage, the jaw and neck, and the lower legs are the sites most often affected.

In areas where a wound is under constant tension (the middle of the chest, the shoulder, over joints), the likelihood of a raised scar is higher. A keloid can also develop after a small spot, an insect bite or an ear piercing; the wound does not have to be large.

What options are there for scars and keloids?

No method erases a scar completely; the aim is to flatten and soften the scar, fade its colour and reduce itching and pain. With keloids, no single method works for everyone; physicians often use several methods together, with long-term follow-up. Which method is suitable is decided by examination, taking into account the type, site, size and age of the scar and how it has responded to previous treatments.

There are also other medicines injected into the scar and combined treatments; your physician decides which will be used and at what intervals. For how lasers work and the recovery process, see the article “Fractional Laser”.

For gels containing onion extract, plant oils and many products sold as scar creams, the evidence is weak or conflicting. Keeping a newly healed wound moist, not stretching it and protecting it from the sun, on the other hand, are simple, generally accepted measures; the sun can darken the colour of a new scar.

If a keloid is removed surgically, does it come back?

This is one of the most important features of keloids. Cutting out a keloid creates a new wound in the skin, and in a person who is prone this new wound may also heal with a keloid. The American Academy of Dermatology states that almost all keloids removed by surgery alone come back; the NHS likewise writes that, for the same reason, surgery is not usually recommended and that the scar may come back larger.

This is why, when surgery is considered, it is planned together with additional methods after the operation, such as injections, pressure, silicone or radiotherapy, and long-term follow-up is needed. Current treatment algorithms state that for small, single keloids surgery and additional treatment can be used together, while for large and multiple keloids the aim is most often to reduce their size and relieve complaints. No method brings the risk of recurrence down to zero.

If you are prone to keloids, what should you watch out for with aesthetic procedures, piercings and tattoos?

In a person who is prone, any intervention that injures the skin can be the start of a new keloid. This does not mean that no procedure can be done; however, the decision needs to be made with this risk in mind.

• Piercings: the safest option is not to have one. The earlobe and especially the ear cartilage are places where keloids are common. If you have had one and notice thickening around the hole, see a physician without waiting; having it pierced again is not recommended.
• Tattoos and tattoo removal: both injure the skin. Not having them reduces the risk; if you are determined to go ahead, mention your predisposition and discuss a small test area.
• Aesthetic procedures: before procedures that injure the skin, such as laser, medium and deep chemical peels, needling treatments and thread lifts, be sure to tell the physician about your history of keloids and any similar scars in your family. The physician may postpone the procedure or suggest a more superficial option or a small test area.
• Surgery and dental procedures: a necessary operation should not be postponed for fear of keloids; however, telling the surgeon in advance allows the site of the incision and the subsequent scar care to be planned accordingly.
• Acne: early and effective acne treatment reduces the risk of scarring; squeezing and picking spots increases it.

If you notice thickening, hardening or itching in a scar after an injury or a procedure, it is important to seek advice early; methods such as pressure and silicone are more effective when started early. For everything that needs to be explained to the physician before a procedure, see the articles “Preparing for a Medical Aesthetic Procedure” and “Medical Aesthetics for People on Medication or with Chronic Conditions”. The risks of having an aesthetic procedure at home or outside a healthcare facility are explained in the article “Needle-Free Filler Pens and At-Home Treatments”.

When should you see a physician?

You do not have to see a physician about an old scar that is not bothering you and is not growing. If a raised scar bothers you or is growing, early assessment may help to stop the growth.

A keloid does not turn into cancer; however, not every raised area that resembles a keloid is a keloid. Some rare skin tumours and other conditions can look similar. In a lesion with the features above, the diagnosis is made by examination and, where necessary, by taking a tissue sample.

Realistic expectations

• A scar does not disappear completely; the aim is a scar that is flatter, softer, closer in colour to its surroundings and less bothersome.
• Treatment often takes months and needs repeated sessions.
• A keloid can come back even after successful treatment; this is why follow-up is important.
• Hypertrophic scars may also regress on their own over time; not every raised scar needs immediate intervention.
• If a scar is distressing you emotionally, share this with your physician; camouflage make-up and psychological support are also among the options.