Here it is, nearing the end of another summer and I finally get the sunscreen issue addressed. My sincerest apologies for that. We are still working the kinks out of our new blog page, but hopefully you are finding it useful. I will say that some good has come of my delay. The FDA has recently announced some new regulations on sunscreen that we can address in the process. Here are a few of the questions we providers get on a routine basis.
Question: What is SPF?
Answer: SPF stands for “sun protection factor” and it is a measure of only UVB protection. Basically the SPF number is a measure of a person’s additional protection from developing erythema (redness) in the presence of UVB light. For example, if I put my arm into a UVB light box and after 2 minutes in the box I develop erythema on my arm, my minimal erythema dose is 2 minutes. So if I now use an SPF of 15 on my arm and do the same test it will take 30 minutes before I get red. The most common misconception is that this number is a time like 15 means 15 minutes of protection. How long SPF protects people is dependent on their skin type.
Skin type is rated on a scale from 1 to 6 and basically indicates how your skin responds to sun. For instance, I am a skin type 2 because I burn pretty easy but I can tan and don’t have to burn to do so. A skin type 1 always burns and never tans. A skin type 6 would be a very dark person that never burns.
Question: What SPF should I use and how often should I reapply?