I have had Guttate psoriasis, a type that youngsters get. Very small patches, about the size of the tip of the thumb, all over the abdo & legs. I was plastered with them. Some patches did spread into each other, and I had to wear slacks to hide the state of my skin. It was dreadful.
It started after several doses of antibiotics for a chest infection.
This was also the start of my problems with GERD, except no one realised it.
It was acid reflux which caused the chest problem.
My Doc after many treatments found the answer ..... and the psoriasis cleared.
8 years later I still have the problems with reflux etc and the prospect of surgery, however I spotted a small area of psoriasis on the front of my Rt leg , mid calf last month. So far its static. I am keeping a very careful eye on it.
I think this time its stress that could be the cause. Although I did have antibiotics for H.pylori a few months ago.
I was in my 50s when mine started. As for medications I have had various PPI's, Ranitidine, and Gaviscon by the bucket, plus mastic capsules etc etc etc..