Sun damage runs the spectrum from a sprinkling of freckles to lethal skin cancer.
It's a continuum, says a world expert in its treatment, New York dermatologist Darrell S. Rigel.
A clinical professor at New York University Medical Centre and former head of the American Academy of Dermatologists he is an in-demand international speaker. With a Manhattan practice, Dr Rigel is also a hands-on practitioner who talks passionately about how to preserve the skin to ward off melanoma.
"The analogy I give my patients is you're like a meter in a taxi, the meter only goes forward and if there's more sun and you're not protected then the meter will go faster. So you can't really turn it backwards very much, but you can slow it down with protection."
That means sunscreen, of course, but it is on the subject of other measures to protect and enhance the appearance of compromised skin that he is most informative. He says there is much that can be done to rejuvenate and also plenty of "snake oil" out there.
Dr Rigel was in Australia last month to address colleagues at a conference when Viva spoke to him about the latest researched thinking in his field. Having visited New Zealand four times, he is familiar with the our greater risks of sun damage and higher rates of melanoma and impressed also by greater public awareness than in the States.
"Unlike many other cancers where we don't always know the cause, this is one where we do. The vast majority of skin cancers are caused by unprotected sun exposure."
Protection is better than cure and in melanoma's case, if let undiagnosed for too long it may be too late for that anyway.
Dr Rigel says within health circles there is much debate on where money should best be spent, in encouraging prevention or bolstering detection. Public health campaigns to encourage sun awareness have worked well, but so does enhancing early diagnosis so melanoma is treatable. A melanoma the size of a $1 coin has a 50 per cent chance of having already spread. The disease grows horizontally first, then moves on to a dangerous vertical progression. In its first stage at under 1mm deep there is a good chance of successful treatment; once it is deeper than 4mm, the chance of survival is 50/50. "If you see a spot that looks funny, have it checked." It could be a life-or-death decision.
And wear a hat. Dr Rigel says one third of all skin cancers occur on the nose. A study in Australia suggests that for every 2.5cm extra width on the brim of a hat worn regularly, skin cancer rates could drop by about 10 per cent. "Everyone's nose sticks out."
Reduced mortality rates are the ultimate measure of success. He tips this to happen, and says Australasia is likely to lead the way. People are taking better care of themselves than 20 years ago, sunscreen has improved - SPF15 sunscreens weren't available until the late 1980s - and new technology and research into treatments offers extra hope.
In a few years GPs will commonly use hand-held devices to scan spots for early signs of problems, reducing the need for biopsies. Trials are under way into drugs that target genetic mutations and block cell paths where cancers grow.
Lasers already offer skin a chance to "back-up a bit" on the ticking sun-exposure meter. Women choosing to have skin rejuvenation procedures aren't just improving their appearance. Melanoma is a cancer of the melanocytes, the body's pigment cells. "Anything that lowers the damage on the skin actually helps, in many cases, remove incipient skin cancers and pre cancers."
"The best and simple thing you can do is wear sunscreens regularly; clearly it does lower that risk of getting damage.
"Beyond that there's some ways to treat damage: certainly mild chemical peels are helpful because it's not just removing that upper layer, some of the peels, like those with alpha hydroxy acid or retinoids/retinol will in fact lower the risk and improve some of the damage that you see."
Dr Rigel said dermatologists used to have two different lasers, now they might have 10, each with differing wave lengths and a different advantage. Non-ablative lasers are popular, but the trade-off was their gentler approach required multiple treatments to be effective.
They can get rid of freckles, broken blood vessels and fine lines. New imperfections may arise, but there is less risk of this if skin is sun protected.
In the case of brown spots it depends on how deep-seated damage is. No one laser does everything.
"With Fraxel lasers, which are basically drilling micro-holes in the skin, you can get rid of some fine lines and you can also get rid of large pores. If you go deeper, do carbon dioxide resurfacing, you can get rid of a lot more but there's risk, it's risk and reward.
"People who have that deep CO2 resurfacing you can always tell they've had something done, the skin looks a little too pink, a little too polished."
Baby-faced Nicole Kidman springs to my mind. Dr Rigel agrees that in certain celebrity faces work can be overdone. "It's too perfect."
I wonder though if the lasering itself, causing skin inflammation, might be damaging long-term? He says no, provided it is done properly. "You've taken a lot of the sun damage off, the pre-cancers off, because again that's part of the ageing process you're fixing."
The wounding from ablative laser is controlled, he says, selectively attacking the tissue you are trying to wipe out with minimal damage to surrounding tissue. "You control it by wave length, by the length of time that the laser beam is out there and the time between pulses."
That's where a trained and experienced operator comes in. Dr Rigel reckons powerful lasers should only be in professional hands, rather than those of beauty therapists. In New Jersey they must be operated by a physician; New York says under the supervision of one; while here it is more open slather.
"Sometimes you are going to be okay if you are an aesthetician, but you don't understand the ramifications of some of the things you are doing, to me that's the risk that you could burn skin. Ninety-nine times out of 100 you might be okay, but it's a subtle thing and you can cause damage."
He says any risks that laser cleaning up of pigmentation might obscure early signs of melanoma are "slight", but another reason to employ a trained eye.
What about the much-touted claims that lasers help with collagen regeneration? It depends on the laser, he says, but the answer is yes.
"What you see with Fraxels for example, where you are drilling micro-channels in the skin, you do get collagen remodelling. But even if I was to inject Restalyne or Juviderm, which is the hyaluronic acid, the matrix of putting that down in a couple of series of injections would actually generate some of your own collagen."
Topically though things are less clear cut. Beyond the acknowledged effectiveness of retinoids in skincare and the ability of hydro-quinones to lighten some superficial spots, Dr Rigel says antioxidants can help skin a little bit.
"All these extra ingredients put in the topical things have to be put in at a level where they have some therapeutic effect. With cosmetics and cosmeceuticals, that, he says, is too often not the case. "You can say antioxidants in big bold letters, but it is probably not at a level where that's therapeutically real."
Clever marketing and testimonials from gullible or high-profile people, rather than evidence-based research, are too often used to sell products. "The average consumer doesn't realise what's a marketing claim and what's a scientific study."
He rates the scientific research done by many of the big pharmaceutical and cosmetic companies, but says some little companies are "one-trick ponies".
Dr Rigel says his own profession isn't immune from hype, with a number of dermatologists having their own skincare ranges. They need to tread carefully to ensure that ethically they aren't overdoing it.
"The classic thing is Pro-Active, it was started by two dermatologists. That is some mild salicylic acid, that does work, there's no question about it, but it's not a revolutionary product and yet they sell US$1 billion dollars a year of Pro-Active. Great marketing."
The appeal of finding ways to hold back ageing is huge, with an ageing consumer society out there. "A lot of very smart people are working on it, the problem is that there's also a lot of snake oil out there. Anyone who hits on something that is a winner is going to do quite well."
Keep your skin healthy, by looking after yourself.
* Eat well, especially food high in antioxidants, such as coloured fruit and vegetables.
* Take oxygenating exercise, but also learn ways to relax. Stress really does show in your face.
* Show sun sense and wear sunscreen, the higher factor the better.
* Get any suspicious marks or lesions on skin checked promptly. (Look for asymmetry, irregularity and colour and size variations. Anything ulcerated or bleeding requires urgent attention.)
* Check out Viva's brand new Facebook page, the place to find out what's hot in fashion, beauty, food, wine and design.