Occasionally people tell me their skin no longer tans as it used to. This isn't the kind of consistent finding that has a name, or for that matter an implication. If your skin doesn't tan, you're better off using a good sunblock (or avoiding the sun), whether you used to tan before or not. Perhaps you should have your skin checked completely. Again, however, I don't think this means much of anything.
Best.
Dr. Rockoff