Keloid or hypertrophic scar: how can you tell?

A piercing hole that never quite settled. A surgical line that looked fine for a month and then started to thicken. An acne lesion that healed into something firm and raised. At some point you press it with a fingertip and notice it's harder than the skin around it, darker or redder, and occasionally itchy when clothing brushes past.

Most people search for how to remove it. That's the wrong first question. Before any treatment makes sense, there's one thing to look at: whether the raised tissue is staying inside the boundary of the original wound, or pushing out into skin that was never injured. That single observation changes the timeline, the expectations, and the order in which options get considered.

This guide walks through what to check first, where keloids and hypertrophic scars actually diverge, and how to think about the months ahead.

This article summarizes treatment information from BeautyStone Clinic in Hongdae, Seoul. Individual results vary, and whether a procedure suits you is a decision to make with a board-certified dermatologist.

Start With the Border, Not the Size

Start With the Border, Not the Size

When a scar thickens, the first thing worth examining isn't how big or how red it is. It's the edge. Is the raised tissue confined to where the skin was actually damaged, or has it crept sideways into skin that was never cut? Dermatology references describe this plainly: keloids extend beyond the margins of the original wound while hypertrophic scars stay within the damaged skin.

That distinction matters because both start in the same place. Both involve collagen being laid down excessively in the dermis*. The difference is where the process stops. In a hypertrophic scar it halts at the wound edge. In a keloid it keeps going.

Dermis: the skin layer beneath the surface epidermis, where collagen and elastic fibers sit and where a thickening scar is actually being built

Timing gives you a second clue. Hypertrophic scars usually rise within weeks of the injury. Keloids can take months, and sometimes years, before they start growing. When someone says a scar looked completely healed and then came back larger much later, that history points in one direction.

Location is a third. Shoulders, the front of the chest, and upper arms are high-tension areas where both types show up. Earlobes are the classic keloid site. If a firm nodule appears behind a piercing a few months after it was done, that's worth having looked at rather than watched indefinitely.

Start With the Border, Not the Size

Where the Two Diverge Over Time

Where the Two Diverge Over Time

After the border, the next question is direction of travel. A hypertrophic scar typically grows, stops, and then gradually flattens and fades over a long stretch. A keloid rarely settles on its own. Left alone it tends to hold its size or slowly enlarge.

That difference is what sets the timing of any intervention. With a hypertrophic scar, watching carefully while keeping up supportive care is often a reasonable plan. With a keloid, waiting usually doesn't buy anything, so if the tissue is visibly expanding it's worth discussing options earlier rather than later.

Published scar management algorithms put numbers on the first half of that table: hypertrophic scars typically grow for three to six months before flattening out. That window is why the early months get treated as their own phase — too early to judge the endpoint, but exactly the right time to have supportive care running.

One honest caveat: telling them apart by eye alone isn't always possible. An early keloid can look like a hypertrophic scar, and an old hypertrophic scar can feel as firm as a keloid. That's why a consultation asks when it appeared, how it's changed, and whether anyone in the family has had something similar — the history carries as much weight as the appearance.

Why BeautyStone Clinic Puts Scars on a Timeline First

Why BeautyStone Clinic Puts Scars on a Timeline First

At BeautyStone Clinic in Hongdae, Seoul, a scar consultation starts with when it began and how it has changed since, not only with how it looks today. A scar that's six weeks old and still growing and a scar that's been unchanged for two years may be the same size while calling for different approaches. So the date of the injury, the change in color and thickness, and whether there's been itching or tenderness all get mapped out before anything is recommended.

Why BeautyStone Clinic Puts Scars on a Timeline First

What Order the Options Usually Follow

What Order the Options Usually Follow

The starting point is almost always supportive: reduce irritation, keep the area moisturized, and apply pressure. Clinical references list consistent moisturizing with massage and silicone sheeting as the baseline step. These carry little downside and reward an early start, which makes them sensible even while the picture is still unclear.

If supportive care alone isn't enough, the next conversation is usually about intralesional steroid injection*. The same scar algorithm recommends running topical and injected medication consistently for at least three months, and stepping up if the response falls short.

Intralesional steroid injection: medication delivered directly into the raised scar tissue to suppress the excess collagen production driving the thickening

Surgery sits in a different position in the sequence. The American Academy of Dermatology notes that nearly all keloids return when they're removed by surgery alone, so dermatologists often recommend combining more than one type of treatment. Excision isn't a standalone answer for a keloid; it's an option that gets planned alongside something else.

So the usual order looks like this: reduce irritation and establish moisturizing and silicone first, add a medication step based on the response, then decide whether a combination approach is warranted. Reassessing every few months beats trying to settle it in one appointment.

What to Bring to a Scar Consultation

What to Bring to a Scar Consultation

The most useful thing you can bring is a record. The date of the injury or procedure, when the scar first started rising, and how the size has shifted over recent months all feed directly into the assessment. Two or three photographs taken from the same angle under the same lighting make the change far easier to read than memory does.

Note whether there's itching or pain, and what kind. A scar that only stings when clothing rubs it differs from one that aches at rest, and that can shift priorities. If you've had a scar thicken like this somewhere else before, mention that too.

Finally, it helps to set expectations in advance. Managing a raised scar is less about erasing a mark and more about lowering its height and reducing redness and discomfort over time. Framing it that way makes the view a few months out much easier to live with.