Oops, missed a couple of posts, someone else addressed this.
I have psoriatic arthritis. It's not the lesions that are painful. I'm assuming Alex is on Humira or Embril or whatever other top-quality meds are out there. The lesions go away really quickly on those meds. But the joint damage if there is any, is permanent, and can make playing a guitar very difficult. My left index and ring finger are permanently bent at the top knuckle. With my smaller hands, it makes playing certain songs on bass impossible. I can only imagine how difficult guitar chords would be.
Yes, that's what I have heard, I have psorasis on my feet and palms of my hands and it can be a pain. My insurance doesn't want to pay for the fancy drugs but I am doing better now I am retired. Stress really makes it flare up and I am not struggling with it as much now which is nice.