Why a scar turns out badly (and why a keloid comes back)

It is worth starting with the distinction that orders everything else, because the whole treatment depends on it and because the two are constantly confused.

Hypertrophic is not the same as keloid

A hypertrophic scar is thick and red but stays within the limits of the original wound, and tends to improve on its own over time.

A keloid grows beyond those limits, invades healthy skin that was never injured, does not improve on its own and has a strong tendency to return.

They are not degrees of the same problem: they behave differently and are treated differently. The practical test is to look at where it ends: if the raised area goes outside the line of the wound, it is a keloid.

The mistake to avoid

Here is the point that settles most consultations: excising a keloid and stitching, with nothing else, makes it come back in the great majority of cases, and often larger than the original, because the new wound is bigger than the one before.

Anyone offering to remove your keloid in one session and leave it flat is not describing what is going to happen.

Keloid treatment is always combined — injections, compression, silicone sheets and, in selected cases, surgery within a protocol — and it is sustained over months. There is no shortcut, and the shortcut that gets sold is expensive in every sense.

What makes a scar turn out badly

Several things, and nearly all of them can be influenced:

• Tension. The single most important factor. A wound closed under tension, or in an area that moves a lot — shoulder, chest, back, flexion creases — heals worse. That is why the same person can have an invisible scar on the face and a thick one on the shoulder.
• Direction. A scar that follows the natural lines of the skin disappears; one that crosses them stays visible and tends to widen.
• How long it took to close. The longer a wound takes to close, the worse the scar. That is why a deep burn leaves more of a mark than a clean cut.
• The sun. A young scar exposed to the sun pigments, and that pigmentation can be permanent.
• Personal predisposition. Darker skin and certain family histories are more prone to keloids. If you have had one before, say so before any surgery.

The months that decide

A scar is not final until twelve to eighteen months have passed. During that time it goes through a red, raised and sometimes uncomfortable phase that frightens people a great deal and is largely normal.

What actually works in that period is unglamorous and has to be sustained: silicone sheets or gel daily for months, massage once the wound has closed, strict sun protection and, where appropriate, compression. Pharmacy creams with promising names do considerably less than consistent silicone.

When to be seen

Before six months, if the scar grows, hardens, itches or hurts. That is when injections do most and when surgery is almost never needed.

Waiting for it "to finish forming" before being seen is the commonest pattern, and it is the one that lets established keloids arrive which would have responded far better six months earlier.

What is not promised

Erasing the scar is not promised: no treatment removes one. What is promised is work to make it flatter, paler, narrower and to stop it hurting or itching, with an improvement that in many cases is considerable. And being told when the best thing is to leave it alone.