Can someone have psoriatic arthritis without having psoriasis?

My mother started developing psoriasis couple of weeks ago and I have to admit that it is not a pretty sight, and she is also very disturbed by it. I just hope that there will not be arthritic problems, because I have heard that it is very much possible. I know that psoriatic arthritis is not possible without arthritis, but can someone have psoriatic arthritis without having psoriasis?

I have to say that I am not sure, but logically, you either have psoriasis, arthritis or psoriatic arthritis. So, theoretically, you can have psoriatic arthritis without psoriasis, but it is called arthritis then. Simple. And PS really is the most complex of these three conditions, and only with meds the symptoms can be subdued.

I am 35 years old and have been diagnosed as having psoratic arthritis and I do not have psoriasis.
Most of the the symptoms do match with the exception of not having psoriasis.
These symptoms only started 2 years ago.