If you suspect that you might have Psoriasis then you should visit a dermatologist to find out for sure. One you make your dermatologist appointment, I would recommend making preparations, especially by writing everything you need to remember on a piece of paper. Your goal should be to get all your concerns and questions addressed. If you don’t come with specific questions and concerns in hand, then there is a fair chance that the doctor will rush you out of the room in an attempt to get to his next appointment.
The last time I visited a dermatologist, I got about 3 minutes of face time, which ended up being completely useless to me. This was partially my fault because I expected him to ask probing questions or do something proactive to see if my concerns were valid (this was expecting too much I guess). The appointment ended as abruptly as it started, with him looking at me crossly the whole time as if I was interrupting him while he was doing something else that was much more important. He listened for a minute, took a glance at my scalp, said it didn’t look too bad, then gave me a prescription for the equivalent of T-Sal, which, ironically, did not work as well as over-the-counter T-Sal (plus the copay was more than T-Sal would have cost by itself).
All this to say, be prepared for your visit. Don’t be defensive, mind you, but if you are prepared you won’t have to be defensive. Know what your concerns are, have a list of specific symptoms and don’t let yourself be rushed. Keep in mind that there are bound to be at least a handful of dermatologists within a 10-15 minute drive of your house (if you live in a city), so if one is unhelpful, you can always make an appointment elsewhere.