Sun on a new scar is paid for a year later

The scar is doing well. It closed on time, it is flat, you barely notice it. Then comes a weekend at the beach, and a few days later there is a brown line where there used to be a pale one. It does not hurt, it does not open, nothing dramatic happened. And a year later it is still there.

That is why sun protection appears in every set of scar instructions, and also why almost nobody follows it: what the sun does here does not look like damage. It looks like a tan.

What a young scar cannot do yet

Normal skin has an orderly pigment system. The cells that make melanin are evenly distributed, they pick up the signal from the sun, they produce more, and when the stimulus goes away the tone slowly returns to where it was. That is a tan: it goes up and it comes back down.

A recent scar does not have that system finished. The skin covering it is new and thinner, and its population of pigment cells is disorganised: in some spots there are too many and in others not enough. When the sun hits, the result is not an even tone that fades later, but a patchy response that can become fixed in the tissue.

That gives the problem two faces. In most cases the scar darkens and ends up browner than the skin around it. In others, less often, the pigment never comes back and the line stays white, paler than everything else. Both are hard to correct afterwards, and both were prevented by the same thing.

And there is a second issue beyond colour: radiation keeps the inflammation switched on. A scar that is in its red phase and takes sun on top of that takes longer to settle, and a scar that stays inflamed longer is a scar with more chances to thicken.

Twelve months, not one summer

A scar does not finish forming when the wound closes. It keeps changing for twelve to eighteen months: red and raised at first, then gradually flatter and paler. As long as it is still red or pink, it is young, and as long as it is young the sun will pigment it.

The working figure is one year of strict protection from surgery, not one season. If the scar is still red when the year is up, the deadline stretches.

On the Peruvian coast this is not a holiday matter. Ultraviolet radiation here is high all year round, and Lima's grey sky is not a filter: clouds let through a good share of the rays that cause pigmentation. The scar that gets marked in January at the beach and the one that gets marked in July walking downtown at midday are the same scar.

What to use, exactly

First of all: sunscreen goes on closed skin. If the wound has a scab, is weeping, or still has stitches in, it does not get sunscreen. Until then the sun is avoided, not filtered.

Once it is closed:

• SPF 50 or higher, and it has to say broad spectrum. The high number only measures protection against the radiation that burns. The radiation that causes pigmentation is a different one, and it is only covered if the label says broad spectrum or UVA.
• Texture: cream or stick rather than spray. Not because spray is bad, but because almost nobody applies enough of it. A stick has a practical advantage on a scar: you run it along the line without spreading it over the whole area, and you can see whether it is covered.
• If the scar is very recent, go mineral. Physical filters made of zinc oxide or titanium dioxide sit on top instead of being absorbed, and new skin tolerates them better. They usually leave a whitish film; on a thin line that does not matter.
• Tinted, if your skin is brown. On medium and darker skin it is not only ultraviolet radiation that causes pigmentation: visible light does too. Tinted sunscreens, the ones containing iron oxides, are the ones that cover that part.
• It gets reapplied. Every two hours if you are outdoors, and after swimming or sweating. One application at eight in the morning does not protect you at midday.

But clothing beats cream

This is the real order, and it is worth being clear about it because sunscreen tends to be the only part anyone remembers: shade first, then clothing, and cream for whatever is left exposed.

A scar under a T-shirt is already protected, and better protected than by any SPF, because fabric does not forget to reapply itself. So the useful question is not which cream to buy, but where your scar is and what you wear over it. A tummy tuck scar lives under clothing eleven months of the year and gets uncovered on exactly one day: the beach day. An eyelid or neck scar is exposed all the time.

At the beach or the pool, what works is clothing: a swim shirt with sleeves, a sarong, a long-sleeved top for the walk there. The silicone sheets many patients already use at night double as a barrier here, because they are opaque. And an umbrella helps but does not solve it: sand and water reflect upwards, and radiation still reaches you underneath.

Tanning does not blend it in

This is the part most often done backwards, and almost always with good intentions. The reasoning sounds sensible: my scar is paler than my skin, so if I tan, the two will even out and it will show less.

The opposite happens. The healthy skin around it tans and, within a few weeks, returns to its own tone. The scar pigments and stays. What you have at the end of summer is not a line that blends in better: it is a darker line on skin that has already gone back to what it was. The contrast ends up greater than it was at the start.

Tanning does not blend a scar in. It sets it.

The same goes for tanning beds, which concentrate precisely the kind of radiation that causes pigmentation, and for the trick of getting a little sun "just to even out the tone". If what you want is for it to show less, what makes a scar less visible is being flat and pale, and that is achieved by covering it, not by exposing it. For the months when you want it hidden, there is cover makeup, which leaves no mark.

If it has already darkened

It is not irreversible in every case. Recent pigmentation can fade over months, especially if from now on the scar stops getting sun, and that is the first treatment: protection is not too late, it is in time for what is left.

What you should not do is start on your own with lightening creams on a young scar. Several of them irritate, an irritated scar inflames, and inflammation is part of what darkened it in the first place. There are treatments that work and each has its moment: some can be used early, others need the tissue to be mature.

When to come in

Before the year is up, if the scar is darkening, if it has been red for more than three or four months without fading, or if it is thickening. Those are three different things, and all three are easier to manage early than late.

And before summer, if you have had recent surgery and a beach trip in the calendar: that five-minute conversation about what to cover, with what, and for how long is what prevents the appointment a year from now, once the colour has set.