Ask an Expert: Now that summer is in full swing, how can I best protect my skin from the sun?

Dr. Vincent Ho reminds us that while a glowing tan may look great, sunning our skin without protection poses serious long-term side effects.

Q: What are the latest recommendations in terms of SPF strength that people should be wearing?
SPF 30. It used to be SPF 15 but most people don’t apply a thick enough coating. If you’re diligent in applying sunscreen, you can use SFP15, however, as a margin of safety we recommend SPF30.

Q: Is it true that I should put my sunscreen on at least 30 minutes before I go outside? What other application tips do I need to remember?
Sunscreen is like a shield – you put it on and it works immediately. The 30 minutes gives it time to bind with your skin so it does not rub off easily. The sunscreen should work immediately upon application.

In terms of application tips: the thicker the coating the better (within reason) and wearing some sort of SPF is always better than not wearing anything. Remember that no matter the how much you think you’ve applied, if you still get red, you haven’t put on enough. Thicker cream sunscreens generally stay on better and protect better than sprays. And finally, obviously, clothing that doesn’t permit sun is an excellent UV blocker.

Q: Why are people with fairer skin at greater risk for sun damage?
Pigment in our skin is protection against the sun. So, if you’re fair, you don’t have much pigment and the sun will cause more damage to your skin.

Q: What types of sun damage skin changes should I be aware of and present to my family doctor?
Look for persistent lesions that become crusted or bleed. Pigmented spots that become very irregular and asymmetrical in pigment or shape should be checked out.

Q: Is getting a ‘base tan’ an effective way to prevent getting sunburned?
In my opinion, the UV protection from priming (base) tans is inadequate. The idea is that you use a low dose to prime the skin. Some people believe that by getting a low dose mild tan, they’ll stimulate more pigment production and that’ll prevent getting burned as easily. However, the amount of protection provided by this priming tan is equivalent to an SPF of about three or four, so it’s really not adequate.

Q: What is the link between sun exposure and skin cancer?
If you don’t protect your skin, UV rays can damage it. UV rays cause free radicals and inflammation as well as mutations of skin cells that give rise to cancer. Even if you don’t think of cancer, all these free radicals accelerate the aging process. So, if you don’t protect your skin, you’ll age faster and have a higher risk of getting skin cancer.

UV damage is cumulative. If you start young abusing skin with too much sun, the damage builds up over time and eventually you cross a threshold that results in skin cancer.

Two factors are important in causing skin cancers: genetic predisposition and ultraviolet damage. We tell our patients: genetics you can’t change but sun exposure you can.


Dr. Vincent Ho is Professor of Dermatology at the University of British Columbia and Head of the Department of Dermatologic Oncology at the British Columbia Cancer Agency.  Dr. Ho’s clinical and research interests include dermatologic therapeutics and oncology, and he brings his experience in pharmacology to his research and patients.  As part of his work at the BC Cancer Agency, Dr. Ho is closely involved in cancer prevention campaigns such as the “‘Sun Awareness Week” and “Mole Patrol”.


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