Q: I've been reading a lot about sunburn and its relationship to skin cancer. What's the best kind of sunscreen to put on my children?
You are right to note that sunburn during childhood or adolescence increases an individual's risk for developing skin cancer in adult life.
A: You may not be aware that excessive sun exposure also leads to premature wrinkling of the skin.
These are two compelling reasons for ensuring that children are adequately protected from the sun.
Sunlight contains two types of radiation, ultraviolet A and B.
Both harm the skin in different ways.
When looking for a sunscreen, you should make sure that it offers protection against both.
Also important is the SPF (sun protection factor), which is a measure of how effectively the sunscreen works.
An SPF of 10 indicates that an individual using the sunscreen could spend up to 10 times longer in the sun without burning than if he or she did not use it.
Parents must know their children's tolerance for sun exposure in order to determine how frequently the sunscreen must be applied. In general, an SPF of at least 15 is recommended.
However, the SPF only applies to ultraviolet B. No rating system for ultraviolet A currently exists.
Because our society seems to prize tanned skin, the natural tendency is to minimize the need for sunscreen.
Parents tend to use less sunscreen than is necessary and forget to reapply it after swimming.
Sunscreens that are waterproof or water resistant can be applied less often.
But we recommend an extra application after swimming if there is any uncertainty about the need for more.
The Skin Cancer Foundation rates many sunscreens; look for their seal of approval.
Dr. Wilson is director of general pediatrics at the Johns Hopkins Children's Center; Dr. Joffe is director of adolescent medicine.