How do you know if you have PUPPS?

For those of you ladies who are going through /experienced PUPPS. How'd you know ? And at how many weeks does it usually occur or last ?? I'm currently 22 weeks as of today and I'm so itchy I get tiny little bumps on my booty cheeks , thighs, my arms get a little itchy so does my back mostly at night or whenever I lay in bed and very little itchiness during the day . I know it's just me because I asked my husband if he got itchy or anything and he said no . I wash our bedding every week, we have a brand new mattress so I know it's not anything bed related.. I have not changed soaps or detergent . This itching just started about a week or so ago . I don't see the Dr until next Thursday but I'm still curious about PUPPS fill me in please 👐👐👐👐👐👀👀👀👀👀