What is the name of and cause of this scary mental illness?

I was wasting time online and found an entire page of people who see friends , family or co-workers out in public but don’t recognize them . They go into a panic when the person looks vaguely familiar since they’re afraid of being approached. Say if you work with “Dave’ and you see Dave in the store which is a new place to see Dave and you don’t know if it’s him or what his name is so you panic. What is this illness? And no; I do not have this problem.