i had it when pregnant with my son. it showed up around 35 weeks only on the belly, but eventually spread to my legs and arms. also unfortunately, mine was one of the rare cases that lasted for about 4 weeks postpartum. sucked. several nurses at the hospital said it was one of the worst cases they'd ever seen.
i got little to no relief no matter what i did, but some things would help very temporarily. keeping the area moisturized and taking warm (not hot) showers with very mild soap. a 1% hyrdrocortisone cream (though you should note that prolonged use of any topical steroid like that can thin your skin and increase scarring). when it first started my OB said that an antihistamine like Benadryl was safe to take; i took that at night since it makes me drowsy. after a few weeks that wasn't enough though and i could not stop scratching all day, so she prescribed me Atarax, a stronger prescription antihistamine. it worked somewhat but also made me drowsy and unable to drive. after delivery i was able to manage it with only the creams and topical treatments.
for what it's worth, my OB told me PUPPPs actually is very likely to recur with subsequent pregnancies. lucky me!