What worked for me...
Have had Delayed Pressure Urticaria, DPU, for 7 years. White male, 60 years old. Active surfer before DPU.
A couple years ago I started using montelukast, 10mg daily. Montelukast helped make life tolerable. I learned to always sit on a cushion and not do anything that involved either hard pressure on any flesh or long pressure on any flesh. Montelukast did not remove all symptoms but reduced the occurrence of major swelling. I still had 10-40 small hives occurring daily. My hands itched badly all day. During sleep I scratched all hives and my hands until the skin was broken. It was similar to having dozens of mosquito bites that had been scratched to bleeding, then scabbed over, then scratched to bleeding again. This pattern of repeatedly scratching the same spots left many small scars. Extreme fatigue was a major component of my DPU. A trip to the grocery wore me out and required a couple hours on the couch to recover. Many days I spent 15 hours laying down (including nighttime).
3 months ago I started receiving monthly shots of Xolair. From the first day my symptoms completely disappeared. No hives, no itching, no fatigue. No recurrence in 3 months. I stopped taking montelukast after the second dose - now 2 months ago.