A few years ago I have noticed that on my beard appeared regions without
hair. I went to dermatologist and she said, that it it an "alopecia areata"
syndrome, which is harmless and of unknown origin. Some people relate it
to stress (it may match my case, becase at the time I had a lot of problems).
She said also, that the hair will problably grow back again.

It may be the case, i.e. in some regions which here hairless the hair grew
back, then some new regions appeared where the hair was lost.

So, my question is: can someone do anything against it ? To protect, say,
against getting such hairless spots on the top of the head ?
Is the origin of this strange hair behaviour really unknown ?

Thanks

        Zenon.